U.S. patent application number 10/932148 was filed with the patent office on 2005-02-10 for process for producing chlorine.
This patent application is currently assigned to SUMITOMO CHEMICAL COMPANY, LIMITED. Invention is credited to Abekawa, Hiroaki, Hibi, Takuo, Iwanaga, Kiyoshi, Oizumi, Takahiro, Seki, Kohei, Suzuki, Tatsuya, Suzuta, Tetsuya.
Application Number | 20050031529 10/932148 |
Document ID | / |
Family ID | 27576864 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050031529 |
Kind Code |
A1 |
Hibi, Takuo ; et
al. |
February 10, 2005 |
Process for producing chlorine
Abstract
A process for producing chlorine by oxidizing hydrogen chloride
with oxygen. The process uses various supported ruthenium catalysts
or a catalyst system containing (A) an active component of a
catalyst and (B) a compound having thermal conductivity of a solid
phase measured by at least one point within a range from 200 to
500.degree. C. of not less than 4 W/m. .degree. C. Specifically, in
the drafted Abstract, we proposed to delete the detailed
description of various supported ruthenium catalysts which is
present on pages 12 and 13 of the specification and in Claim 1.
Inventors: |
Hibi, Takuo; (Ichihara-shi,
JP) ; Abekawa, Hiroaki; (Sodegaura-shi, JP) ;
Seki, Kohei; (Chiba-shi, JP) ; Suzuki, Tatsuya;
(Niihama-shi, JP) ; Suzuta, Tetsuya;
(Ichihara-shi, JP) ; Iwanaga, Kiyoshi;
(Ichihara-shi, JP) ; Oizumi, Takahiro;
(Sendai-shi, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
SUMITOMO CHEMICAL COMPANY,
LIMITED
|
Family ID: |
27576864 |
Appl. No.: |
10/932148 |
Filed: |
September 2, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10932148 |
Sep 2, 2004 |
|
|
|
09249100 |
Feb 12, 1999 |
|
|
|
Current U.S.
Class: |
423/502 ;
502/325 |
Current CPC
Class: |
C01B 7/04 20130101; B01J
23/6522 20130101; B01J 23/462 20130101 |
Class at
Publication: |
423/502 ;
502/325 |
International
Class: |
C01B 007/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 16, 1998 |
JP |
10-032677 |
Feb 25, 1998 |
JP |
10-043292 |
Mar 5, 1998 |
JP |
10-053366 |
Mar 5, 1998 |
JP |
10-053367 |
Mar 26, 1998 |
JP |
10-079034 |
Apr 7, 1998 |
JP |
10-094680 |
Apr 10, 1998 |
JP |
10-099615 |
Apr 21, 1998 |
JP |
10-110618 |
May 12, 1998 |
JP |
10-128709 |
Oct 15, 1997 |
JP |
09-281782 |
Feb 5, 1998 |
JP |
10-024740 |
Claims
1. A process for producing chlorine by oxidizing hydrogen chloride
with oxygen, wherein said process uses one catalyst selected from
the following catalysts (1) to (9): (1) a supported ruthenium oxide
catalyst obtained by the steps which comprise supporting a
ruthenium compound on a carrier, treating the supported one by
using a basic compound, treating by using a reducing compound, and
oxidizing; (2) a supported ruthenium oxide catalyst obtained by the
steps which comprise supporting a ruthenium compound on a carrier,
treating the supported one by using a reducing agent to form
ruthenium having an oxidation number of 1 to less than 4 valence,
and oxidizing; (3) a supported ruthenium oxide catalyst obtained by
the steps which comprise supporting a ruthenium compound on a
carrier, reducing the supported one by using a reducing
hydrogenated compound, and oxidizing; (4) a supported ruthenium
oxide catalyst obtained by using titanium oxide containing rutile
titanium oxide as a carrier; (5) a supported ruthenium oxide
catalyst obtained by the steps which comprise supporting a
ruthenium compound on a carrier, treating the supported one by
using a reducing compound or reducing agent in a liquid phase, and
oxidizing, wherein titanium oxide contains an OH group in an amount
of 0.1.times.10.sup.-4 to 30.times.10.sup.-4 (mol/g-carrier) per
unit weight of the carrier; (6) a catalyst system containing the
following component (A), and not less than 10% by weight of
component (B): (A) an active component of catalyst; (B) a compound
wherein thermal conductivity of a solid phase measured by at least
one point within a range from 200 to 500.degree. C. is not less
than 4 W/m. .degree. C.; (7) a supported ruthenium oxide catalyst
having a macro pore with a pore radius of 0.03 to 8 micrometer; (8)
an outer surface-supported catalyst obtained by supporting
ruthenium oxide on a carrier at the outer surface; and (9) a
supported ruthenium catalyst obtained by using chromium oxide as a
carrier.
2. The process according to claim 1 (1), wherein the reducing
compound is a compound selected from the group consisting of
hydrazine, methanol, ethanol, formaldehyde, hydroxylamine, formic
acid and compounds having a oxidation-reduction potential of -0.8
to 0.5 V.
3. The process according to claim 1, wherein the catalyst (2) is a
supported ruthenium oxide catalyst obtained by the steps which
comprise supporting at least one ruthenium compound selected from
the group consisting of ruthenium halide, chlororuthenate salt,
oxyruthenate salt, rutheniumoxy chloride, ruthenium-ammine complex,
chloride of ruthenium-ammine complex, ruthenium acetylacetonato
complex, ruthenium organic acid salt and ruthenium-nitrosyl complex
on a carrier, treating the supported one by using a reducing agent
to form ruthenium having an oxidation number of 1 to less than 4
valence, and oxidizing.
4. The process according to claim 1, wherein the catalyst (2) is a
supported ruthenium oxide catalyst obtained by the steps which
comprise supporting at least one ruthenium compound selected from
the group consisting of ruthenium halide, chlororuthenate salt,
oxyruthenate salt, rutheniumoxy chloride, ruthenium-ammine complex,
chloride of ruthenium-ammine complex, ruthenium acetylacetonato
complex, ruthenium organic acid salt and ruthenium-nitrosyl complex
on a carrier, treating the supported one by using a basic compound,
treating by using a reducing agent, and oxidizing.
5. The process according to claim 1 (2), wherein the reducing agent
is a reducing compound.
6. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
ruthenium halide on a carrier, treating the supported one by using
hydrazine, methanol, ethanol or formaldehyde, and oxidizing.
7. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
a ruthenium compound on a carrier, treating the supported one by
using an alkali solution of hydrazine, methanol, ethanol or
formaldehyde, and oxidizing.
8. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
a ruthenium compound on a carrier, treating the supported one by
using an alkali, treating by using a reducing compound, and
oxidizing.
9. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst prepared by supporting
a ruthenium compound on a carrier, treating the supported one by
using an alkali solution of a reducing compound, and oxidizing.
10. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
ruthenium halide on a carrier, treating the supported one by using
an alkali, treating by using hydrazine, methanol, ethanol or
formaldehyde, and oxidizing.
11. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
ruthenium halide on a carrier, treating the supported one by using
an alkali solution of hydrazine, methanol, ethanol or formaldehyde,
and oxidizing.
12. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
ruthenium halide on a carrier, treating the supported one by adding
an alkali, treating by using hydrazine, and oxidizing.
13. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
ruthenium halide on a carrier, treating the supported one by using
an alkali solution of hydrazine, and oxidizing.
14. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
ruthenium halide on a carrier, treating the supported one by adding
an alkali, treating with hydrazine, adding an alkali metal
chloride, and oxidizing.
15. The process according to claim 1, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by supporting
ruthenium halide on a carrier, treating the supported one by using
an alkali solution of hydrazine, adding an alkali metal chloride,
and oxidizing.
16. The process according to claim 1, wherein the catalyst (3) is a
supported ruthenium oxide catalyst obtained by supporting a
ruthenium compound on a carrier, reducing the supported one by
using a reducing hydrogenated compound, and oxidizing.
17. The process according to claim 1, wherein the catalyst (3) is a
supported ruthenium oxide catalyst obtained by supporting a
ruthenium compound on a carrier, reducing the supported one by
using a reducing hydrogenated compound, adding an alkali metal
chloride, and oxidizing.
18. The process according to claim 1, wherein the catalyst (3) is a
supported ruthenium oxide catalyst obtained by supporting ruthenium
halide on a carrier, reducing the supported one by using an alkali
metal boron hydride compound, and oxidizing.
19. The process according to claim 1, wherein the catalyst (3) is a
supported ruthenium oxide catalyst obtained by supporting ruthenium
hydride on a carrier, reducing the supported one by using an alkali
metal boron hydride compound, adding an alkali metal chloride, and
oxidizing.
20. The process according to claim 1, wherein the catalyst (3) is a
supported ruthenium oxide catalyst obtained by supporting ruthenium
chloride on a carrier, reducing the supported one by using sodium
boron hydride, and oxidizing.
21. The process according to claim 1, wherein the catalyst (3) is a
supported ruthenium oxide catalyst obtained by supporting ruthenium
chloride on a carrier, reducing the supported one by using sodium
boron halide, adding an alkali metal chloride, and oxidizing.
22. The process according to claim 1, wherein the catalyst (1), (2)
or (3) is a supported ruthenium oxide catalyst obtained by using
titanium oxide containing not less than 10% by weight of rutile
titanium oxide as a carrier.
23. The process according to claim 1, wherein the catalyst (1), (2)
or (3) is a supported ruthenium oxide catalyst obtained by using
titanium oxide containing not less than 30% by weight of rutile
titanium oxide as a carrier.
24. The process according to claim 1, wherein the catalyst (4) is a
supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 0.1.times.10.sup.-4 to 30.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
25. The process according to claim 1, wherein the catalyst (4) is a
supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 0.2.times.10.sup.-4 to 20.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
26. The process according to claim 1, wherein the catalyst (4) is a
supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 3.times.10.sup.-4 to 15.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
27. The process according to claim 1, wherein the catalyst (4) or
(5) is a supported ruthenium oxide catalyst obtained by using
titanium oxide containing not less than 10% by weight of rutile
titanium oxide as a carrier.
28. The process according to claim 1, wherein the catalyst (4) or
(5) is a supported ruthenium oxide catalyst obtained by using
titanium oxide containing not less than 30% by weight of rutile
titanium oxide as a carrier.
29. The process according to claim 1, wherein the catalyst (5) is a
supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 0.2.times.10.sup.-4 to 20.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
30. The process according to claim 1, wherein the catalyst (5) is a
supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 3.times.10.sup.-4 to 15.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
31. The process according to claim 1, wherein the catalyst (4) or
(5) is a supported ruthenium oxide catalyst obtained by supporting
a ruthenium compound on a carrier, reducing the supported one by
using a reducing hydrogenated compound, and oxidizing.
32. The process according to claim 1, wherein the catalyst (4) or
(5) is a supported ruthenium oxide catalyst obtained by supporting
a ruthenium compound on a carrier, treating the supported one by
using a reducing compound, and oxidizing.
33. The process according to claim 1, wherein the catalyst (4) or
(5) is a supported ruthenium oxide catalyst obtained by supporting
a ruthenium compound on a carrier, treating the supported one by
using an alkali solution of a reducing compound, and oxidizing.
34. The process according to claim 1, wherein the catalyst system
(6) is a catalyst system at least containing a component (A), a
component (B) and a catalyst carrier component.
35. The process according to claim 1, wherein the catalyst system
(6) is a catalyst made of a molding containing a component (A) and
a component (B) obtained by integrally molding.
36. The process according to claim 1, wherein the catalyst system
(6) is a catalyst made of a molding containing a component (A), a
component (B) and a catalyst carrier component obtained by
integrally molding.
37. The process according to claim 35, wherein the catalyst is made
of a molding containing the component (A) supported on the
component (B).
38. The process according to claim 36, wherein the catalyst is made
of a molding containing both the component (A) supported on the
catalyst carrier component and the component (B).
39. The process according to claim 36, wherein the catalyst is made
of the molding containing the component (A) supported on a mixture
of the catalyst carrier component with the component (B).
40. The process according to claim 1, wherein the catalyst system
(6) is a catalyst system containing both of a molding containing
the component (A) and the component (B) obtained by integrally
molding and a molding containing the component (B) obtained by
integrally molding.
41. The process according to claim 1, wherein the catalyst system
(6) is a catalyst system comprising both of a molding containing
the component (A) with the catalyst carrier component obtained by
integrally molding and a molding containing a component (B)
obtained by integrally molding.
42. The process according to claim 1 (6), wherein the component (B)
is .alpha.-alumina.
43. The process according to claim 1 (6), wherein the component (A)
is a component containing ruthenium.
44. The process according to claim 43, wherein the component (A) is
a component containing ruthenium oxide.
45. The process according to claim 44, wherein the component (B)
and/or the catalyst carrier component is a component containing
titanium oxide.
46. The process according to claim 1, wherein the catalyst (7) is
an outer surface-supported catalyst obtained by supporting
ruthenium oxide on a carrier at the outer surface.
47. The process according to claim 1, wherein the catalyst (8) is
an outer surface-supported catalyst prepared by an alkali
preliminary impregnation process.
48. The process according to claim 1, wherein the catalyst (9) is a
ruthenium oxide catalyst supported on chromium oxide.
49. The process according to claim 1, wherein the catalyst (9) is a
catalyst obtained by calcining a ruthenium chloride catalyst
supported on chromium oxide.
50. A process for producing a supported ruthenium oxide catalyst
selected from the following processes (1) to (5): (1) a process for
producing a supported ruthenium oxide catalyst, which comprises the
steps of supporting a ruthenium compound on a carrier, treating the
supported one by using a basic compound, treating by using
compound, and oxidizing; (2) a process for producing a supported
ruthenium oxide catalyst, which comprises the steps of supporting a
ruthenium compound on a carrier, treating the supported one by
using a reducing compound to form ruthenium having an oxidation
number of 1 to less than 4 valence, and oxidizing; (3) a process
for producing a supported ruthenium oxide catalyst, which comprises
the steps of supporting a ruthenium compound on a titanium oxide
carrier containing rutile titanium oxide, treating the supported
one by using a reducing agent, and oxidizing; (4) a process for
producing a supported ruthenium oxide catalyst, which comprises the
steps of supporting a ruthenium compound on a titanium oxide
carrier containing an OH group in an amount of 0.1.times.10.sub.-4
to 30.times.10.sup.-4 (mol/g-carrier) per unit weight of a carrier,
treating the supported one by using a reducing agent, and
oxidizing; and (5) a process for producing a supported ruthenium
oxide catalyst containing ruthenium oxide only at an outer surface
layer, not less than 80% of the outer surface of said catalyst
satisfying the following expression (1):S/L<0.35 (1)wherein L is
a distance between a point (A) and a point (B), said point (B)
being a point formed on the surface of a catalyst when a
perpendicular line dropped from any point (A) on the surface of the
catalyst to the inside of the catalyst goes out from the catalyst
at the opposite side of the point (A), and S is a distance between
the point (A) and a point (C), said point (C) being a point on the
perpendicular line where ruthenium oxide does not exist, wherein
said process comprises supporting an alkali on a carrier,
supporting at least one ruthenium compound selected from the group
consisting of ruthenium halide, rutheniumoxy chloride,
ruthenium-acetylacetonato complex, ruthenium organic acid salt and
ruthenium-nitrosyl complex on the carrier, treating by using a
reducing agent, and oxidizing.
51. The process according to claim 50 (2), wherein said process
comprises the steps of supporting at least one ruthenium compound
selected from the group consisting of ruthenium halide,
chlororuthenate salt, oxyruthenate salt, rutheniumoxy chloride,
ruthenium-ammine complex, chloride of ruthenium-ammine complex,
ruthenium-acetylacetonato complex, ruthenium organic acid salt and
ruthenium-nitrosyl complex on a carrier, treating the supported one
by using a reducing agent to form ruthenium having an oxidization
number of 1 to less than 4 valence, and oxidizing.
52. The process according to claim 50 (2), wherein said process
comprises the steps of supporting at least one ruthenium compound
selected from the group consisting of ruthenium halide,
chlororuthenate salt, oxyruthenate salt, rutheniumoxy chloride,
ruthenium- ammine complex, chloride of ruthenium-ammine complex,
ruthenium-acetylacetonato complex, ruthenium organic acid salt and
ruthenium-nitrosyl complex on a carrier, treating the supported one
by using a basic compound, treating by using a reducing agent, and
oxidizing.
53. The process according to claim 50 (2), wherein the reducing
agent is a reducing compound.
54. The process according to claim 50 (1) or (2), wherein said
process comprises supporting ruthenium halide on a carrier, adding
an alkali to the supported one, treating by using a reducing
compound, and oxidizing.
55. The process according to claim 50 (1) or (2), wherein said
process comprises supporting ruthenium halide on a carrier,
treating the supported one by using an alkali solution of a
reducing compound, and oxidizing.
56. The process according to claim 50 (1) or (2), wherein said
process comprises supporting ruthenium halide on a carrier, adding
an alkali to the supported one, treating by using a reducing
compound, adding an alkali metal chloride, and oxidizing.
57. The process according to claim 50 (1) or (2), wherein said
process comprises supporting ruthenium halide on a carrier,
treating the supported one by using an alkali solution of a
reducing compound, adding an alkali metal chloride, and
oxidizing.
58. The process according to claim 50 (1) or (2), wherein said
process comprises supporting ruthenium halide on a carrier, adding
an alkali to the supported one, treating by using hydrazine, and
oxidizing.
59. The process according to claim 50 (1) or (2), wherein said
process comprises supporting ruthenium halide on a carrier,
treating the supported one by using an alkali solution of
hydrazine, and oxidizing.
60. The process according to claim 50 (1) or (2), wherein said
process comprises supporting ruthenium halide on a carrier, adding
an alkali to the supported one, treating by using hydrazine, adding
an alkali metal chloride, and oxidizing.
61. The process according to claim 50 (1) or (2), wherein said
process comprises supporting ruthenium halide on a carrier,
treating the supported one by using an alkali solution of
hydrazine, adding an alkali metal chloride, and oxidizing.
62. The process according to claim 50, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by using
titanium oxide containing not less than 10% by weight of rutile
titanium oxide as a carrier.
63. The process according to claim 50, wherein the catalyst (1) or
(2) is a supported ruthenium oxide catalyst obtained by using
titanium oxide containing not less than 30% by weight of rutile
titanium oxide as a carrier.
64. The process according to claim 50 (3) or (4), wherein the
titanium oxide is titanium oxide containing not less than 10% of
rutile titanium oxide.
65. The process according to claim 50 (3) or (4), wherein the
titanium oxide is titanium oxide containing not less than 30% of
rutile titanium oxide.
66. The process according to claim 50 (3) or (4), wherein said
process comprises supporting a ruthenium compound on a carrier,
reducing the supported one by using a reducing hydrogenated
compound, and oxidizing.
67. The process according to claim 50 (3) or (4), wherein said
process comprises supporting a ruthenium compound on a carrier,
treating the supported one by using a reducing compound, and
oxidizing.
68. The process according to claim 50 (3) or (4), wherein said
process comprises supporting a ruthenium compound on a carrier,
treating the supported one by using an alkali solution of a
reducing compound, and oxidizing.
69. The process according to claim 50 (3), wherein the catalyst is
a supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 0.1.times.10.sup.-4 to 30.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
70. The process according to claim 50 (3), wherein the catalyst is
a supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 0.2.times.10.sub.-4 to 20.times.10.sub.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
71. The process according to claim 50 (3), wherein the catalyst is
a supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 3.times.10.sup.-4 to 15.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
72. The process according to claim 50 (3) or (4), wherein the
catalyst is obtained by supporting a ruthenium halide on carrier,
treating the supported one by using a reducing compound, and
oxidizing.
73. The process according to claim 50 (3) or (4), wherein the
catalyst is obtained by supporting a ruthenium halide on carrier,
treating the supported one by using an alkali solution of a
reducing compound, and oxidizing.
74. The process according to claim 50 (4), wherein the catalyst is
a supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 0.2.times.10.sup.-4 to 2 0.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
75. The process according to claim 50 (4), wherein the catalyst is
a supported ruthenium oxide catalyst obtained by the steps which
comprise supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, wherein titanium oxide containing an
OH group in an amount of 3.times.10.sup.-4 to 15.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier.
76-87 (canceled).
88. The process according to claim 43, wherein the component (B)
and/or the catalyst carrier component is a component containing
titaium oxide.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a divisional of Application No. 09/249,100 filed
Feb. 12, 1999; the disclosure of the above noted prior application
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a process for producing
chlorine. More particularly, the present invention relates to a
process for producing chlorine by oxidizing hydrogen chloride with
oxygen, wherein said process can produce chlorine by using a
catalyst having high activity in a smaller amount at a lower
reaction temperature. The above invention also relates to a process
for producing chlorine by oxidizing hydrogen chloride, wherein said
process can facilitate control of the reaction temperature by
making it easy to remove the reaction heat from catalyst bed using
a catalyst having good thermal conductibility, which can be formed
by containing a compound having high thermal conductivity of a
solid phase, and can achieve high reaction conversion by keeping
the whole catalyst bed at sufficient temperature for industrially
desirable reaction rate.
[0004] The present invention also relates to a process for
producing a supported ruthenium oxide catalyst. More particularly,
the present invention relates to a process for producing a
supported ruthenium oxide catalyst, wherein said process is a
process for producing a catalyst having high activity and can
produce a catalyst having high activity capable of producing the
desired compound by using a smaller amount of the catalyst at a
lower reaction temperature.
[0005] Furthermore, the present invention relates to a supported
ruthenium oxide catalyst. The present invention relates to a
supported ruthenium oxide catalyst, wherein said catalyst has high
activity and can produce the desired compound by using a smaller
amount of the catalyst at a lower reaction temperature.
[0006] 2. Description of the Related Art
[0007] It is well known that chlorine is useful as a raw material
of vinyl chloride, phosgene, etc., and can be produced by oxidizing
hydrogen chloride. For example, the Deacon reaction by using a Cu
catalyst is well known. For example, British Patent No. 1,046,313
discloses a process for oxidizing hydrogen chloride by using a
catalyst containing a ruthenium compound, and also discloses that
ruthenium (III) chloride is particularly effective among the
ruthenium compounds. Furthermore, a process for supporting a
ruthenium compound on a carrier is also disclosed and, as the
carrier, silica gel, alumina, pumice and ceramic material are
exemplified. As the Example, a ruthenium chloride catalyst
supported on silica is exemplified. However, a test was conducted
using a catalyst prepared by using a process for preparing a
ruthenium (III) chloride supported on silica disclosed in said
patent publication. As a result, the ruthenium compound as a
catalyst component is drastically volatilized and it was
disadvantageous for industrial use. For example, European Patent
EP-0184413A2 discloses a process for oxidizing hydrogen chloride by
using a chromium oxide catalyst. However, conventionally known
processes had a problem that the activity of the catalyst is
insufficient and high reaction temperature is required.
[0008] When the activity of the catalyst is low, a higher reaction
temperature is required but the reaction of oxidizing hydrogen
chloride with oxygen to produce chlorine is an equilibrium
reaction. When the reaction temperature is high, it becomes
disadvantageous in view of equilibrium and the equilibrium
conversion of hydrogen chloride decreases. Therefore, when the
catalyst has high activity, the reaction temperature can be
decreased and, therefore, the reaction becomes advantageous in view
of equilibrium and higher conversion of hydrogen chloride can be
obtained. In case of the high reaction temperature, the activity is
lowered by volatilization of the catalyst component. Also in this
point of view, it has been required to develop a catalyst which can
be used at low temperature.
[0009] Both high activity per unit weight of catalyst and high
activity per unit weight of ruthenium contained in the catalyst are
required to the catalyst, industrially. Since high activity per
unit weight of ruthenium contained in the catalyst can reduces the
amount of ruthenium contained in the catalyst, it becomes
advantageous in view of cost. It is possible to select the reaction
condition which is more advantageous in view of equilibrium by
conducting the reaction at a lower temperature using a catalyst
having high activity. It is preferred to conduct the reaction at a
lower temperature in view of stability of the catalyst.
[0010] The catalyst used in the oxidizing reaction of hydrogen
chloride includes, for example, a supported ruthenium oxide
catalyst prepared by supporting ruthenium chloride on a carrier,
drying the supported one, heating in a hydrogen gas flow to form a
supported metal ruthenium catalyst, and oxidizing the catalyst.
When ruthenium chloride is reduced with hydrogen, sintering of
ruthenium occurs, which results in decrease of activity of the
resulting catalyst.
[0011] A process for preparing ruthenium oxide supported on a
carrier without causing sintering of ruthenium during the
preparation step of a catalyst is preferred. First, a process has
been desired which is not a process for reducing at high
temperature by using hydrogen, but a process for preparing
ruthenium oxide on a carrier with preventing sintering by treating
a ruthenium compound with a mixture of a basic compound and a
reducing compound, or a mixture of an alkali compound and a
reducing compound, and oxidizing the treated one.
[0012] Second, a process has been desired which is a process for
preparing ruthenium oxide on a carrier with preventing sintering by
oxidizing after passing through a state of an oxidation number of 1
to less than 4 valence without preparing a ruthenium compound
having an oxidation number of 0 valence by completely reduction
[0013] Third, it has been desired to develop a catalyst preparing
process which can obtain a highly active hydrogen chloride
oxidizing catalyst by passing through a preparation of a highly
dispersed supported metal ruthenium catalyst, when the preparation
is carried out by supporting a ruthenium compound on a carrier,
reducing the supported one in order to prepare supported metal
ruthenium catalyst, and oxidizing to prepare a supported ruthenium
oxide catalyst.
[0014] A supported ruthenium oxide catalyst obtained by using an
anatase crystalline or non-crystalline titanium oxide as a carrier
was highly active to oxidation of hydrogen chloride, but it has
been required to develop a catalyst having higher activity.
[0015] In the case of a conventional carrier which the content of
an OH group on the surface of titanium oxide is too large or small,
a catalyst having high activity was not obtained and the catalytic
activity decreased sometimes as time passed.
[0016] When the oxidizing reaction of hydrogen chloride is
conducted at a higher reaction rate with conventionally known
catalysts, heat generated as a result of the high reaction rate can
not be sufficiently removed and the temperature of the catalyst bed
increases locally and, therefore, the reaction temperature can not
be easily controlled.
[0017] Furthermore, when the reaction is conducted by using these
catalysts, a large temperature distribution occurs in the catalyst
bed and it is impossible to keep the whole system at sufficient
temperature for industrially desirable reaction rate without
exceeding upper temperature limit for keeping high catalyst
activity. Therefore, the reaction conversion is lowered.
[0018] As a process for increasing the rate of removing heat
generated during the reaction, for example, a process for
increasing a heat transfer area in contact with external coolant
per volume of the catalyst bed is known. However, when the heat
transfer area becomes large, the cost of a reactor increases. On
the other hand, when heat is removed by cooling the catalyst bed
from outside, heat transfers to an external coolant through the
catalyst bed and the heat transfer surface. When the thermal
conductivity of the catalyst is improved, the heat removing rate
increases. Therefore, it has been required to develop a catalyst
having good thermal conductibility, which can increase the heat
removing rate, to avoid difficulty of control of the reaction
temperature.
[0019] It is generally considered that, when a carrier supporting
an active component of the catalyst is mixed with an inactive
component at the ratio of 1:1, the activity per volume or per
weight reduced to half. Therefore, it is required to develop a
catalyst having good thermal conductivity as described above and
further to develop a catalyst having high activity which the
activity of the catalyst per volume or per weight does not
decrease.
[0020] It is known that, since a supported catalyst is generally
prepared by supporting on a carrier having porediameters of from 30
to 200 angstroms, the rate-determining step of the reaction is
controlled by the catalyst pore diffusion control and it is
difficult to improve the activity of the catalyst. Therefore, it
has been required to develop a catalyst having macropores which the
inside of the catalytic particles can be utilized
[0021] As a result, since the reaction proceeds in the vicinity of
the outer surface of the catalytic particles, it is considered that
ruthenium oxide supported on the outer surface of the carrier is
used in the reaction but ruthenium oxide supported in the catalytic
particles is not used in the reaction. Therefore, it has been
required to develop a catalyst obtained by supporting ruthenium
oxide on the outer surface of the catalyst.
[0022] It is also known that a ruthenium oxide catalyst is useful
as a catalyst in process for preparing chlorine by an oxidizing
reaction of hydrogen chloride and is obtained by hydrolyzing
ruthenium chloride, oxidizing the hydrolyzed one, and calcining the
oxidized one. For example, European patent EP-0743277A1 discloses
that a ruthenium oxide catalyst supported on titanium oxide is
obtained by hydrolyzing a ruthenium compound by using an alkali
metal hydroxide, supporting the hydrolyzed one on titanium
hydroxide, and calcining the supported one under air. The present
inventors have found that the supported ruthenium oxide catalyst is
obtained by oxidizing a supported metal ruthenium catalyst. As a
process for preparing the supported metal ruthenium catalyst, for
example, it is known that a process for preparing a supported metal
ruthenium catalyst by supporting ruthenium chloride on a carrier,
drying the supported one, and heating the dried one in a hydrogen
gas flow. However, there was a problem that a supported ruthenium
oxide catalyst prepared by oxidizing a catalyst reduced by hydrogen
has low activity due to sintering of ruthenium when ruthenium
chloride is reduced with hydrogen.
[0023] A process for preparing ruthenium oxide supported on a
carrier with preventing sintering has been required. First, a
process has been desired which is not a process for reducing at
high temperature by using hydrogen, but for treating a ruthenium
compound with a mixture of a reducing compound and a basic
compound, or a mixture of an alkali compound and a reducing
compound, and oxidizing the treated one.
[0024] Second, a process has been desired which is a process for
preparing ruthenium oxide on a carrier with preventing sintering by
oxidizing after passing through a state of an oxidation number of 1
to less than 4 valence without preparing a ruthenium compound
having an oxidation number of 0 valence by completely
reduction.
[0025] In general, it is difficult to reduce the ruthenium compound
with a reducing compound, unlike platinum and palladium. For
example, because of this , there is a problem that a supported
ruthenium oxide catalyst prepared by oxidizing after adding
hydrazine to ruthenium chloride has low activity because of a
formation of complex by adding hydrazine to ruthenium chloride.
[0026] A supported ruthenium oxide catalyst obtained by using an
anatase crystalline or non-crystalline titanium oxide as a carrier
was highly active to oxidation of hydrogen chloride, but it has
been required to develop a catalyst having higher activity.
[0027] In the case of a content of an OH group on the surface of
titanium oxide which is a conventional carrier is too large or
small, a catalyst having high activity was not obtained and the
catalytic activity decreased sometimes as time passed.
[0028] It is known that the rate-determining step of the reaction
is under the catalyst pore diffusion control and it is difficult to
improve the activity of the catalyst since a supported catalyst is
generally prepared by supporting on a carrier having pore diameters
of from 30 to 200 angstroms. As a result, it is considered that
ruthenium oxide supported on the outer surface of the carrier is
used in the reaction but ruthenium oxide supported in the catalytic
particles is not used in the reaction since the reaction proceeds
in the vicinity of the outer surface of the catalytic particles.
Therefore, it has been required to develop a technique for
supporting ruthenium oxide on the outer surface of the
catalyst.
SUMMARY OF THE INVENTION
[0029] It is an object of the present invention is to provide a
process for producing chlorine by oxidizing hydrogen chloride with
oxygen, wherein said process can produce chlorine by using a
catalyst having high activity in a smaller amount at a lower
reaction temperature. One of the above object of the present
invention to provide a process for producing chlorine by oxidizing
hydrogen chloride, wherein said process can facilitate control of
the reaction temperature by making it easy to remove the reaction
heat from catalyst bed using a catalyst having good thermal
conductivity, which can be formed by containing a compound having
high thermal conductivity in solid phase, and can attain high
reaction conversion by keeping the whole catalyst bed at sufficient
temperature for industrially desirable reaction rate capable of
oxidizing hydrogen chloride.
[0030] It is still another object of the present invention to
provide a process for producing a supported ruthenium oxide
catalyst, characterized in that said process is a process for
producing a catalyst having high activity and can produce a
catalyst having high activity capable of the desired compound using
a smaller amount of a catalyst at a lower reaction temperature.
[0031] It is a further object of the present invention to provide a
supported ruthenium oxide catalyst, characterized in that said
catalyst has high activity and can produce the desired compound
using a smaller amount of a catalyst at a lower reaction
temperature.
[0032] That is, the present invention relates to a process for
producing chlorine by oxidizing hydrogen chloride with oxygen,
wherein said process uses one catalyst selected from the following
catalysts (1) to (9):
[0033] (1) a supported ruthenium oxide catalyst obtained by the
steps which comprises supporting a ruthenium compound on a carrier,
treating the supported one by using a basic compound, treating by
using a reducing compound, and oxidizing;
[0034] (2) a supported ruthenium oxide catalyst obtained by the
steps which comprises supporting a ruthenium compound on a carrier,
treating the supported one by using a reducing agent to form
ruthenium having an oxidation number of 1 to less than 4 valence,
and oxidizing;
[0035] (3) a supported ruthenium oxide catalyst obtained by the
steps which comprises supporting a ruthenium compound on a carrier,
reducing the supported one by using a reducing hydrogenated
compound, and oxidizing;
[0036] (4) a supported ruthenium oxide catalyst obtained by using
titanium oxide containing rutile titanium oxide as a carrier;
[0037] (5) a supported ruthenium oxide catalyst obtained by the
steps which comprises supporting a ruthenium compound on a carrier,
treating the supported one by using a reducing compound or reducing
agent in a liquid phase, and oxidizing, wherein titanium oxide
contains an OH group in an amount of 0.1.times.10.sup.-4 to
30.times.10.sup.-4 (mol/g-carrier) per unit weight of a
carrier;
[0038] (6) a catalyst system containing the following components
(A), and not less than 10% by weight of component (B):
[0039] (A) an active component of catalyst;
[0040] (B) a compound wherein thermal conductivity of a solid phase
measured by at least one point within a range from 200 to
500.degree. C. is not less than 4 W/m. .degree. C.;
[0041] (7) a supported ruthenium oxide catalyst having a macro pore
with a pore radius of 0.03 to 8 micrometer;
[0042] (8) an outer surface-supported catalyst obtained by
supporting ruthenium oxide on a carrier at the outer surface;
and
[0043] (9) a supported ruthenium catalyst obtained by using
chromium oxide as a carrier.
[0044] The present invention also relates to a process for
producing a supported ruthenium oxide catalyst selected from the
following processes (1) to (5):
[0045] (1) a process for producing a supported ruthenium oxide
catalyst, which comprises the steps of supporting a ruthenium
compound on a carrier, treating the supported one by using a basic
compound, treating by using a reducing compound, and oxidizing;
[0046] (2) a process for producing a supported ruthenium oxide
catalyst, which comprises the steps of supporting a ruthenium
compound on a carrier, treating the supported one by using a
reducing compound to form ruthenium having an oxidation number of 1
to less than 4 valence, and oxidizing;
[0047] (3) a process for producing a supported ruthenium oxide
catalyst, which comprises the steps of supporting a ruthenium
compound on a titanium oxide carrier containing rutile titanium
oxide, treating the supported one by using a reducing agent, and
oxidizing;
[0048] (4) a process for producing a supported ruthenium oxide
catalyst, which comprises the steps of supporting a ruthenium
compound on a titanium oxide carrier containing an OH group in an
amount of 0.1.times.10.sup.-4 to 30.times.10.sup.-4 (mol/g-carrier)
per unit weight of a carrier, treating the supported one by using a
reducing agent, and oxidizing; and
[0049] (5) a process for producing a supported ruthenium oxide
catalyst containing ruthenium oxide only at an outer surface layer,
not less than 80% of the outer surface of said catalyst satisfying
the following expression (1):
S/L<0.35 (1)
[0050] wherein L is a distance between a point (A) and a point (B),
said point (B) being a point formed on the surface of a catalyst
when a perpendicular line dropped from any point (A) on the surface
of the catalyst to the inside of the catalyst goes out from the
catalyst at the opposite side of the point (A), and S is a distance
between the point (A) and a point (C), said point (C) being a point
on the perpendicular line where ruthenium oxide does not exist,
wherein said process comprises supporting an alkali on a carrier,
supporting at least one ruthenium compound selected from the group
consisting of ruthenium halide, rutheniumoxy chloride,
ruthenium-acetylacetonato complex, ruthenium organic acid salt and
ruthenium-nitrosyl complex on the carrier, treating by using a
reducing agent, and oxidizing.
[0051] The present invention also relates to a supported ruthenium
oxide catalyst obtained by supporting on a titanium oxide carrier
containing not less than 20% by weight of rutile titanium
oxide.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0052] The supported ruthenium oxide catalyst (1) used in the
present invention is a supported ruthenium oxide catalyst obtained
by the steps which comprises supporting a ruthenium compound on a
carrier, treating the supported one by using a basic compound,
treating by using a reducing compound, and oxidizing the resulting
one. In general, said catalyst is industrially used in the form of
being supported on a carrier.
[0053] The supported ruthenium oxide catalyst (2) used in the
present invention is a supported ruthenium oxide catalyst obtained
by the steps which comprises supporting a ruthenium compound on a
carrier, treating the supported one by using a reducing agent to
form ruthenium having an oxidation number of 1 to less than 4
valence, and oxidizing the resulting one.
[0054] The process for preparing the supported ruthenium oxide
catalyst used in the oxidizing reaction of hydrogen chloride
include various processes. For example, a process for preparing a
catalyst comprising ruthenium oxide having an oxidation number of 4
valence supported on a carrier can be prepared by supporting
ruthenium chloride on a carrier, hydrolyzing the supported one by
using an alkali, and calcining under an air. Alternatively, a
process for preparing a catalyst comprising supported ruthenium
oxide having an oxidation number of 4 valence can also be prepared
by supporting ruthenium chloride on a carrier, reducing the
supported one by using various reducing agents to form ruthenium
having a valence of 0, and calcining under an air. It is also
possible to exemplify a preparation example of a supported
ruthenium oxide catalyst comprising supported ruthenium oxide
having an oxidation number of 4, which is prepared by supporting
ruthenium chloride on a carrier, treating the supported one by
using a mixed solution of various reducing compounds and basic
compounds, or treating by using an aqueous alkali solution of a
reducing compound, or treating by using various reducing agents,
thereby to form a ruthenium compound having an oxidation number of
1 to less than 4 valence, and calcining under an air. The catalyst
prepared by this preparation process can be exemplified as a
preparation example which is most active to the oxidizing reaction
of hydrogen chloride. The process of adjusting the oxidation number
of the ruthenium compound supported on the carrier within a range
from 1 to less than 4 valence includes various processes, for
example, process of treating by using a mixed solution of a
reducing compound and a basic compound, process of treating by
using an alkali solution of a reducing compound, process of
treating by using an organolithium compound, an organosodium
compound or an organopotassium compound, process of treating by
using an organoaluminum compound, process of treating by using an
organomagnesium compound, and process of treating by using
hydrogen. When using these reducing agents in an excess amount, the
ruthenium compound is reduced to the valence of 0 and, therefore,
it is necessary to use a suitable amount.
[0055] The process of measuring the oxidation number of the
supported ruthenium includes various processes. For example, since
nitrogen is mainly generated when using hydrazine as the reducing
agent, the valence number of ruthenium can be determined by the
amount of nitrogen generated.
[0056] The reaction scheme will be shown below. 1
[0057] For example, when the ruthenium compound is reduced by using
hydrazine under the conditions of an aqueous alkali solution, a
hydroxide of ruthenium is formed. Therefore, the oxidation number
of ruthenium can be determined by measuring a ratio of ruthenium to
oxygen or chlorine binding to ruthenium due to elemental analysis
after dehydration under vacuum. When using ruthenium chloride as
the ruthenium compound, a hydroxide and a chloride of ruthenium are
formed. Therefore, the oxidation number of ruthenium can also be
determined by measuring a ratio of ruthenium to oxygen and chlorine
binding to ruthenium due to elemental analysis after dehydration
under vacuum.
[0058] In the present invention, the oxidation number of ruthenium
was determined from the amount of nitrogen generated by using the
scheme (1).
[0059] The common part with the catalysts (1) and (2) will be
explained.
[0060] The carrier includes, for example, oxides and mixed oxides
of elements, such as titanium oxide, alumina, zirconium oxide,
silica, titanium mixed oxide, zirconium mixed oxide, aluminum mixed
oxide, silicon mixed oxide and the like. Preferable carriers are
titanium oxide, alumina, zirconium oxide and silica, and more
preferable carrier is titanium oxide.
[0061] The ruthenium compound to be supported on the carrier
include compounds, for example, ruthenium chloride such as
RuCl.sub.3 and RuCl.sub.3 hydrate; chlororuthenate such as
K.sub.3RuCl.sub.6, [RuCl.sub.6].sup.3- and K.sub.2RuCl.sub.6;
chlororuthenate hydrate such as [RuCl.sub.5(H.sub.2O).sub.4].sup.2-
and [RuCl.sub.2(H.sub.2O).sub.4].s- up.+; salt of ruthenic acid,
such as K.sub.2RuO.sub.4; rutheniumoxy chloride such as
Ru.sub.2OCl.sub.4, Ru.sub.2OCl.sub.5 and Ru.sub.2OCl.sub.6; salt of
rutheniumoxy chloride, such as K.sub.2Ru.sub.2OCl.sub.10 and
CsRu.sub.2OCl.sub.4; ruthenium-ammine complex such as
[Ru(NH.sub.3).sub.6].sup.2+, [Ru(NH.sub.3).sub.6].sup.3+ and
[Ru(NH.sub.3).sub.5H.sub.2O].sup.2+; chloride and bromide of
ruthenium-ammine complex, such as [Ru(NH.sub.3).sub.5Cl].sup.2+,
[Ru(NH.sub.3).sub.6] Cl.sub.2, [Ru(NH.sub.3).sub.6]Cl.sub.3 and
[Ru(NH.sub.3).sub.6]Br.sub.3; ruthenium bromide such as RuBr.sub.3
and RuBr.sub.3 hydrate; other ruthenium-organoamine complex;
ruthenium-acetylacetonato complex; ruthenium-carbonyl complex such
as Ru(CO).sub.5 and [Ru.sub.3(CO).sub.12; ruthenium organic acid
salt such as
Ru.sub.3O(OCOCH.sub.3).sub.6(H.sub.2O).sub.3])OCOCH.sub.3 hydrate
and Ru.sub.2(RCOO).sub.4Cl(R=C1-3 alkyl group); ruthenium-nitrosyl
complex such as K.sub.2[RuCl.sub.5(NO)]],
[Ru(NH.sub.3).sub.5(NO)]Cl.sub.3, [Ru(OH) (NH.sub.3).sub.4(NO)]
(NO.sub.3).sub.2 and Ru(NO) (NO.sub.3).sub.3, and
ruthenium-phosphine complex. Preferable compounds are ruthenium
halide compounds, for example, ruthenium chloride such as
RuCl.sub.3 and RuCl.sub.3 hydrate and ruthenium bromide such as
RuBr.sub.3 and RuBr.sub.3 hydrate. More preferred one is a
ruthenium chloride hydrate.
[0062] The process of supporting the ruthenium compound on the
carrier includes, for example, impregnation process and equilibrium
adsorption process.
[0063] The reducing compound used for treating the ruthenium
compound supported on the carrier includes, for example, hydrazine,
methanol, ethanol, formaldehyde, hydroxylamine or formic acid, or
an aqueous solution of hydrazine, methanol, ethanol, formaldehyde,
hydroxylamine or formic acid, or a solution of an organic solvent
such as alcohol. Preferred are hydrazine, methanol, ethanol,
formaldehyde, and solutions of hydrazine, methanol, ethanol and
formaldehyde. More preferred are hydrazine and a solution of
hydrazine. The reducing compound used for treating the ruthenium
compound supported on the carrier includes, for example, a compound
having a redox potential of -0.8 to 0.5 V, a solution thereof, and
a solution of an organic solvent such as alcohol. Now a standard
electrode potential is used in place of the redox potential. Among
the compounds listed above, a standard electrode potential of
hydrazine is -0.23 V, that of formaldehyde is 0.056 V and that of
formic acid is -0.199 V, respectively. It is also a preferable
process to use an aqueous alkali solution of the reducing
compound.
[0064] The basic compound listed as the catalyst (1) includes, for
example, ammonia; amine such as alkyl amine, pyridine, aniline,
trimethylamine and hydroxyl amine; alkali metal hydroxide such as
potassium hydroxide, sodium hydroxide and lithium hydroxide; alkali
metal carbonate such as potassium carbonate, sodium carbonate and
lithium carbonate; and hydroxide of quaternary ammonium salt.
[0065] The basic compound for preparing the catalyst (2) includes,
for example, ammonia; amine such as alkyl amine, pyridine, aniline,
trimethylamine and hydroxyl amine; alkali metal hydroxide such as
potassium hydroxide, sodium hydroxide and lithium hydroxide; alkali
metal carbonate such as potassium carbonate, sodium carbonate and
lithium carbonate; hydroxide of quaternary ammonium salt; and alkyl
aluminum such as triethyl aluminum.
[0066] The process of treating the ruthenium compound supported on
the carrier by using a reducing compound includes, for example, a
process of supporting a ruthenium compound on a carrier, drying the
supported one, and dipping the dried one in a reducing compound or
a solution of a reducing compound, or impregnating with a reducing
compound or a solution of a reducing compound. A process of dipping
in an alkali solution of a reducing compound is also a preferable
process.
[0067] A process of treating by using a reducing compound or an
alkali solution of the reducing compound, and adding an alkali
metal chloride is also a preferable process.
[0068] The process of oxidizing includes, for example, process of
calcining under air.
[0069] A weight ratio of ruthenium oxide to the carrier is
preferably within a range from 0.1/99.9 to 20.0/80.0, more
preferably from 0.5/99.5 to 15.0/85.0, and most preferably from
1.0/99.0 to 15.0/85.0. When the ratio of ruthenium oxide is too
low, the activity is lowered sometimes. On the other hand, when the
ratio of ruthenium oxide is too high, the price of the catalyst
becomes high sometimes. Examples of the ruthenium oxide to be
supported include ruthenium dioxide, ruthenium hydroxide and the
like.
[0070] The embodiment of the process for preparing the supported
ruthenium oxide catalyst used in the present invention include a
preparation process comprising the following steps:
[0071] a ruthenium compound supporting step: step of supporting a
ruthenium compound on a carrier of a catalyst;
[0072] an alkali treating step: step of adding an alkali to one
obtained in the ruthenium compound supporting step;
[0073] a reducing compound treating step: step of treating one
obtained in the alkali treating step by using a reducing compound;
and
[0074] an oxidizing step: step of oxidizing one obtained in the
reducing compound treating step.
[0075] It is also preferred to use an aqueous alkali solution of a
reducing compound to simultaneously conduct the alkali treating
step and the reducing compound treating step in the above step.
[0076] Preferred embodiment of the process of preparing the
supported ruthenium oxide catalyst used in the present invention
include a preparation process comprising the following steps:
[0077] a ruthenium halide compound supporting step: step of
supporting a ruthenium halide compound on a carrier of a
catalyst;
[0078] an alkali treating step: step of adding an alkali to one
obtained in the ruthenium halide compound supporting step;
[0079] a reducing compound treating step: step of treating one
obtained in the alkali treating step by using hydrazine, methanol,
ethanol or formaldehyde; and
[0080] an oxidizing step: step of oxidizing one obtained in the
reducing compound treating step.
[0081] It is also preferred to use an aqueous alkali solution of a
reducing compound to simultaneously conduct the alkali treating
step and the reducing compound treating step in the above step.
[0082] More preferred embodiment of the process of preparing the
supported ruthenium oxide catalyst used in the present invention
include a preparation process comprising the following steps:
[0083] a ruthenium halide supporting step: step of supporting
ruthenium halide on a carrier of a catalyst;
[0084] an alkali treating step: step of adding an alkali to one
obtained in the ruthenium halide supporting step;
[0085] a hydrazine treating step: step of treating one obtained in
the alkali treating step by using hydrazine; and
[0086] an oxidizing step: step of oxidizing one obtained in the
hydrazine treating step.
[0087] It is also preferred to use an aqueous alkali solution of a
hydrazine to simultaneously conduct the alkali treating step and
the hydrazine treating step in the above step.
[0088] More preferred embodiment of the process of preparing the
supported ruthenium oxide catalyst used in the present invention
include a preparation process comprising the following steps:
[0089] a ruthenium halide supporting step: step of supporting
ruthenium halide on a carrier of a catalyst;
[0090] an alkali treating step: step of adding an alkali to one
obtained in the ruthenium halide supporting step;
[0091] a hydrazine treating step: step of treating one obtained in
the alkali treating step by using hydrazine;
[0092] an alkali metal chloride adding step: step of adding an
alkali metal chloride to one obtained in the hydrazine treating
step; and
[0093] an oxidizing step: step of oxidizing one obtained in the
alkali metal chloride adding step.
[0094] It is also preferred to use an aqueous alkali solution of
hydrazine to simultaneously conduct the alkali treating step and
the hydrazine treating step in the above step.
[0095] The ruthenium halide supporting step is a step of supporting
ruthenium halide on a carrier of a catalyst. The ruthenium compound
to be supported on the carrier includes, for example, already
listed various ruthenium compounds. Among them, preferred examples
thereof are halides of ruthenium, for example, ruthenium chloride
such as RuCl.sub.3 and RuCl.sub.3 hydrate and ruthenium bromide
such as RuBr.sub.3 and RuBr.sub.3 hydrate. More preferred one is a
ruthenium chloride hydrate.
[0096] The amount of ruthenium halide used in the ruthenium halide
supporting step is usually an amount corresponding to a preferable
weight ratio of ruthenium oxide to the carrier. That is, ruthenium
halide is supported by using a process of impregnating an already
listed carrier of the catalyst, or a process of performing
equilibrium adsorption. As the solvent, for example, water and an
organic solvent such as alcohol are used, and water is preferred.
The impregnated one can be dried, and can also be treated by using
an alkali without being dried, but it is preferable the impregnated
one is dried. Regarding the conditions for drying the impregnated
one, the drying temperature is preferably from 50 to 200.degree. C.
and the drying time is preferably from 1 to 10 hours.
[0097] The alkali treating step is a step for adding an alkali to
one obtained in the ruthenium halide supporting step. The alkali
used in the alkali treating step includes, for example, hydroxide,
carbonate and hydrogencarbonate of alkali metal; aqueous solution
of ammonia, ammonium carbonate and ammonium hydrogencarbonate; and
solution of an organic solvent such as alcohol. As the alkali, for
example, hydroxide, carbonate and hydrogencarbonate of alkali metal
are preferably used. As the solvent, for example, water is
preferably used. The concentration of the alkali varies depending
on the alkali to be used, but is preferably from 0.1 to 10
mol/l.
[0098] Regarding a molar ratio of the ruthenium halide to alkali
is, for example, 3 mol of sodium hydroxide is equivalent to 1 mol
of ruthenium halide. Preferably, the alkali is used in the amount
of 0.1-20 equivalent per equivalent of ruthenium halide. The
process of adding the alkali include a process of impregnating with
a solution of the alkali or a process of dipping in a solution of
the alkali. The time of impregnation with the solution of the
alkali is usually within 60 minutes. Since the activity of the
catalyst decreases when the impregnation time is long, the
impregnation time is preferably within 10 minutes. The temperature
is preferably from 0 to 100.degree. C., and more preferably from 10
to 60.degree. C.
[0099] The hydrazine treating step is a step of treating one
obtained in the alkali treating step by using hydrazine. The
process of treating by using hydrazine includes, for example, a
process of impregnating with a solution of hydrazine and a process
of dipping in a solution of hydrazine. The supported ruthenium
halide treated by using the alkali in the previous step and an
alkali solution may be added to a hydazine solution in a state of
being mixed, or may be added to the hydazine solution after the
alkaline solution was separated by filtration. A preferable process
is a process of impregnating the supported ruthenium halide with
the alkali and immediately adding to the hydrazine solution. The
concentration of hydrazine used in the hydrazine treating step is
preferably not less than 0.1 mol/l. Hydrazine hydrate such as
hydrazine monohydrate may be used as it is. Alternatively, it is
used as a solution of an organic solvent such as alcohol.
Preferably, an aqueous solution of hydrazine or hydrazine hydrate
is used. Anhydride and a monohydrate of hydrazine can also be used.
Regarding a molar ratio of ruthenium halide to hydrazine, hydrazine
is used in the amount of 0.1 to 20 mol per mol of ruthenium halide.
The time of impregnation with the solution of hydrazine is
preferably from 5 minutes to 5 hours, and more preferably from 10
minutes to 2 hours. The temperature is preferably from 0 to
100.degree. C., and more preferably from 10 to 60.degree. C. After
dipping in the hydrazine solution, the dipping one is preferably
separated from the solution by filtration.
[0100] It is also preferred to use an aqueous alkali solution of
hydrazine to simultaneously conduct the alkali treating step and
hydrazine treating step in the above step. Preferable process
includes a process of slowly dipping one obtained in the ruthenium
halide supporting step to those prepared by mixing a preferable
amount of the alkali with a preferable amount of hydazine, and
treating for 5 minutes to 5 hours.
[0101] More preferable process includes a process of washing a
solid produced in the alkali treating step and hydrazine treating
step, thereby to remove the alkali and hydrazine, drying, adding an
alkali metal chloride in the following alkali metal chloride adding
step, drying, and oxidizing.
[0102] More preferable process includes a process of washing a
solid produced in the alkali treating step and hydrazine treating
step by using an aqueous solution of an alkali metal chloride,
drying, and oxidizing. This process is preferred because the
removal of the alkali and hydrazine, and the addition of the alkali
metal chloride can be conducted in the same step.
[0103] The alkali metal chloride adding step is a step of adding an
alkali metal chloride to one obtained in the alkali treating step
and hydrazine treating step. This step is not an indispensable step
to prepare the supported ruthenium oxide catalyst, but the activity
of the catalyst is further improved by conducting said step. That
is, the resulting solid is oxidized by the following oxidizing
step, but it is a preferable preparation example to convert it into
highly active supported ruthenium oxide by oxidizing the resulting
solid treated with the alkali and hydrazine in the presence of an
alkali metal salt.
[0104] The alkali metal chloride includes, for example, chloride of
alkali metal, such as potassium chloride and sodium chloride.
Preferable alkaline metal chlorides are potassium chloride and
sodium chloride, and more preferable one is potassium chloride. A
molar ratio of the alkali metal salt to ruthenium is preferably
from 0.01 to 10, and more preferably from 0.1 to 5.0. When the
amount of the alkali metal salt used is too small, sufficient
highly active catalyst is not obtained. On the other hand, when the
amount of the alkali metal salt used is too large, the cost becomes
high from an industrial point of view.
[0105] The process of adding the alkali metal chloride includes a
process of impregnating the resulting supported ruthenium one,
obtained by washing, drying, treating by using an alkali and
hydrazine, with an aqueous solution of the alkali metal chloride,
but more preferable process includes a process of impregnating the
resulting supported ruthenium one treated with the alkali and
hydrazine by washing with an aqueous alkali metal chloride solution
without being washed with water.
[0106] For the purpose of adjusting the pH in the case of washing
the resulting supported one, hydrochloric acid can be added to an
aqueous solution of the alkali metal chloride. The concentration of
the aqueous solution of the alkali metal chloride is preferably
from 0.01 to 10 mol/l, and more preferably from 0.1 to 5 mol/l.
[0107] The purpose of washing lies in removal of the alkali and
hydrazine, but the alkali and hydrazine can also be remained as far
as the effect of the present invention is not adversely
affected.
[0108] After impregnating with the alkali metal chloride, the
catalyst is usually dried. Regarding the drying conditions, the
drying temperature is preferably from 50 to 200.degree. C. and the
drying time is preferably from 1 to 10 hours.
[0109] The oxidizing step is a step of oxidizing one obtained in
the alkali treating step and hydrazine treating step (in the case
of using no alkali metal chloride adding step), or a step of
oxidizing one obtained in the alkali metal chloride adding step (in
the case of using the alkali metal chloride adding step). The
oxidizing step can include a process of calcining under an air. It
is a preferable preparation example to convert it into highly
active supported ruthenium oxide by calcining one treated with the
alkali and hydrazine in the presence of an alkali metal salt, in a
gas containing oxygen. A gas containing oxygen usually includes
air.
[0110] The calcination temperature is preferably from 100 to
600.degree. C., and more preferably from 280 to 450.degree. C. When
the calcination temperature is too low, particles formed by the
alkali treatment and hydrazine treatment are remained in a large
amount in the form of a ruthenium oxide precursor and, therefore,
the activity of the catalyst becomes insufficient sometimes. On the
other hand, when the calcination temperature is too high,
agglomeration of ruthenium oxide particles occur and, therefore,
the activity of the catalyst is lowered. The calcination time is
preferably from 30 minutes to 10 hours.
[0111] In this case, it is important to calcine in the presence of
the alkali metal salt. By using this process, it is possible to
obtain higher activity of the catalyst because that process can
form more fine particles of ruthenium oxide, comparing the process
which includes calcining in the substantially absence of the alkali
metal salt.
[0112] By the calcination, the particles supported on the carrier,
which are formed by the alkali treatment and hydrazine treatment,
are converted into a supported ruthenium oxide catalyst. It can be
confirmed by analysis such as X-ray diffraction and XPS (X-ray
photoelectron spectroscopy) that the particles formed by the alkali
treatment and hydrazine treatment were converted into ruthenium
oxide. Incidentally, substantially total amount of particles formed
by the alkali treatment and hydrazine treatment are preferably
converted into ruthenium oxide, but the particles formed by the
alkali treatment and hydrazine treatment can be remained as far as
the effect of the present invention is not adversely affected.
[0113] The process of oxidizing one treated with the alkali and
hydrazine, washing the remained alkali metal chloride, and drying
is a preferable preparation process. It is preferred that the
alkali metal chloride contained on calcination is sufficiently
washed with water. The process of measuring the alkali metal
chloride after washing includes a process of examining the
presence/absence of white turbidity by adding an aqueous silver
nitrate solution to the filtrate. However, the alkali metal
chloride may be remained as far as the effect of the present
invention is not adversely affected.
[0114] According to a preferable preparation process, the washed
catalyst is then dried. Regarding the drying conditions, the drying
temperature is preferably from 50 to 200.degree. C. and the drying
time is preferably from 1 to 10 hours.
[0115] The supported ruthenium oxide catalyst produced by the above
steps is highly active, and the activity was higher than that of
the catalyst prepared by oxidizing a catalyst obtained by reducing
ruthenium chloride with hydrogen. Furthermore, a catalyst obtained
by previously treating ruthenium chloride by using an alkali,
treating by using hydrazine (alternatively, alkali treatment and
hydrazine treatment are simultaneously conducted), and oxidizing
showed higher activity than that of a catalyst obtained by treating
ruthenium chloride with hydrazine, and oxidizing.
[0116] The supported ruthenium oxide catalyst used in the catalyst
(3) of the present invention, which is obtained by reducing a
ruthenium compound supported on a carrier with a reducing
hydrogenated compound, and oxidizing, is a catalyst containing a
supported ruthenium oxide catalyst comprising ruthenium oxide
supported on a carrier. In general, it is industrially used in the
form of being supported on a carrier.
[0117] As the carrier, the same carriers as those used in the
catalysts (1) and (2) of the present invention can be used.
[0118] As the weight ratio of the ruthenium oxide to the carrier,
the same ratio as that in the catalysts (1) and (2) of the present
invention is used.
[0119] As the ruthenium compound to be supported on the carrier,
for example, the same ruthenium compounds as those used in the
catalysts (1) and (2) of the present invention are used.
[0120] The process of supporting the ruthenium compound on the
carrier includes, for example, impregnation process and equilibrium
adsorption process.
[0121] The reducing hydrogenated compound used for reducing the
ruthenium compound supported on the carrier include for example,
boron hydride compound such as NaBH.sub.4, Na.sub.2B.sub.2H.sub.6,
Na.sub.2B.sub.4H.sub.10, Na.sub.2B.sub.5H.sub.9, LiBH.sub.4,
K.sub.2B.sub.2H.sub.6, K.sub.3B.sub.4H.sub.10,
K.sub.2B.sub.5H.sub.9 and Al(BH.sub.4).sub.3; organometallic boron
hydride compound such as LiB[CH(CH.sub.3)C.sub.2H.sub.5].sub.3H,
LiB(C.sub.2H.sub.5).sub.3H, KB[CH(CH.sub.3)C.sub.2H.sub.5].sub.3H
and KB[CH(CH.sub.3)CH(CH.sub.3).sub- .2].sub.3H; metal hydride such
as LiAlH, NaH, LiH and KH; and organometallic hydride such as
[(CH.sub.3).sub.2CHCH.sub.2].sub.2AlH. Preferable reducing agents
are alkali metal boron hydride compound such as NaBH.sub.4,
Na.sub.2B.sub.2H.sub.6, Na.sub.2B.sub.4H.sub.10,
Na.sub.2B.sub.5H.sub.9, LiBH.sub.4, K.sub.2B.sub.2H.sub.6,
K.sub.3B.sub.4H.sub.10 and K.sub.2B.sub.5H.sub.9. More preferable
one is NaBH.sub.4.
[0122] Preferred embodiment of the process of preparing the
supported ruthenium oxide catalyst used in the catalyst (3) of the
present invention include a preparation process comprising the
following steps:
[0123] a ruthenium compound supporting step: step of supporting a
ruthenium compound on a carrier of a catalyst;
[0124] a reducing step: step of reducing one obtained in the
ruthenium compound supporting step by using a reducing hydrogenated
compound; and
[0125] an oxidizing step: step of oxidizing one obtained in the
reducing step; or
[0126] a ruthenium compound supporting step: step of supporting a
ruthenium compound on a carrier of a catalyst;
[0127] a reducing step: step of reducing one obtained in the
ruthenium compound supporting step by using a reducing hydrogenated
compound;
[0128] an alkali metal chloride adding step: step of adding an
alkali metal chloride to one obtained in the reducing step; and
[0129] an oxidizing step: step of oxidizing one obtained in the
alkali metal chloride adding step.
[0130] More preferred embodiment of the process of preparing the
supported ruthenium oxide catalyst used in the catalyst (3) of the
present invention include a preparation process comprising the
following steps:
[0131] a ruthenium halide supporting step: step of supporting
ruthenium halide on a carrier of a catalyst;
[0132] a reducing step: step of reducing one obtained in the
ruthenium hydride supporting step by using an alkali metal boron
halide compound; and
[0133] an oxidizing step: step of oxidizing one obtained in the
reducing compound treating step; or
[0134] a ruthenium halide supporting step: step of supporting
ruthenium halide on a carrier of a catalyst;
[0135] a reducing step: step of reducing one obtained in the
ruthenium halide supporting step by using an alkali metal boron
hydride compound;
[0136] an alkali metal chloride adding step: step of adding an
alkali metal chloride to one obtained in the reducing step; and
[0137] an oxidizing step: step of oxidizing one obtained in the
alkali metal chloride adding step.
[0138] More preferred embodiment of the process of preparing the
supported ruthenium oxide catalyst used in the catalyst (3) of the
present invention include a preparation process comprising the
following steps:
[0139] a ruthenium chloride supporting step: step of supporting
ruthenium chloride on a carrier of a catalyst;
[0140] a reducing step: step of reducing one obtained in the
ruthenium chloride supporting step by using sodium boron hydride;
and
[0141] an oxidizing step: step of oxidizing one obtained in the
reducing step; or
[0142] a ruthenium chloride supporting step: step of supporting
ruthenium chloride on a carrier of a catalyst;
[0143] a reducing step: step of reducing one obtained in the
ruthenium chloride supporting step by using sodium boron
hydride;
[0144] an alkali metal chloride adding step: step of adding an
alkali metal chloride to one obtained in the reducing step; and
[0145] an oxidizing step: step of oxidizing one obtained in the
alkali metal chloride adding step.
[0146] The respective steps will be explained below.
[0147] The ruthenium chloride supporting step is a step of
supporting ruthenium chloride on a carrier of a catalyst. The
amount of ruthenium chloride used in the ruthenium chloride
supporting step is usually an amount corresponding to a preferable
weight ratio of ruthenium oxide to the carrier. That is, a solution
of ruthenium chloride is supported on the already listed carrier of
the catalyst. As the solvent, for example, water and an organic
solvent such as alcohol are used, and water is preferred. A
ruthenium compound other than ruthenium chloride can also be used.
However, when using a compound which does not dissolve in water,
there can be used an organic solvent capable of dissolving it, for
example, hexane and tetrahydrofuran. Then, supported one can be
dried or reduced without being dried, but a process of drying is
preferred. Regarding the conditions for drying the supported one,
the drying temperature is preferably from 50 to 200.degree. C. and
the drying time is preferably from 1 to 10 hours.
[0148] The reducing step is a step of reducing one obtained in the
ruthenium chloride supporting step by using sodium boron hydride
(NaBH.sub.4). The process of the reducing step includes a process
of dipping one obtained in the ruthenium chloride supporting step
in a solution of sodium boron hydride. The sodium boron hydride
solution includes aqueous solution and solution of an organic
solvent such as alcohol, but a mixed solution of water and an
organic solvent can also be used. Preferably, a mixed solution of
water and alcohol is used and, more preferably, a solution of water
and ethanol is used. The concentration of the solution of sodium
boron hydride is usually from 0.05 to 20% by weight, and preferably
from 0.1 to 10% by weight. The molar ratio of the sodium boron
hydride to the supported ruthenium is usually from 1.0 to 30, and
preferably from 2.0 to 15. The catalyst may be washed with water
after reducing, or may be subjected to a step of washing with an
aqueous alkali metal chloride solution as an operation of the
alkali metal chloride adding step. Preferably, a process of
reducing, washing with water, and drying is adopted.
[0149] It is also possible to reduce with a reducing compound other
then sodium boron hydride. In that case, an aprotic anhydrous
solvent is preferably used. For example, a supported ruthenium
compound is reduced with a reducing hydrogenated compound other
than sodium boron halide by using a toluene solvent.
[0150] The alkali metal chloride adding step is a step of adding an
alkali metal chloride to one obtained in the reducing step. This
step is conducted in the same manner as that in the alkali metal
chloride adding step conducted in the catalysts (1) and (2) of the
present invention.
[0151] The oxidizing step is a step of oxidizing one obtained in
the reducing step (in the case of using no alkali metal chloride
adding step), or a step of oxidizing one obtained in the alkali
metal chloride adding step (in the case of using the alkali metal
chloride adding step). This step is conducted in the same manner as
that in the oxidizing step conducted in the catalysts (1) and (2)
of the present invention.
[0152] By the calcination, the metal ruthenium supported on the
carrier is converted into a supported ruthenium oxide catalyst. It
can be confirmed by analysis such as X-ray diffraction and XPS
(X-ray photoelectron spectroscopy) that the metal ruthenium was
converted into ruthenium oxide. Incidentally, substantially total
amount of the metal ruthenium is preferably converted into
ruthenium oxide, but the metal ruthenium can be remained as far as
the effect of the present invention is not adversely affected.
[0153] The process of oxidizing the supported metal ruthenium,
washing the remained alkali metal chloride with water, and drying
is a preferable preparation process. It is preferred that the
alkali metal chloride contained on calcination is sufficiently
washed with water. The process of measuring the alkali metal
chloride after washing includes a process of examining the
presence/absence of white turbidity by adding an aqueous silver
nitrate solution to the filtrate. However, the alkali metal
chloride may be remained as far as the effect of the present
invention is not adversely affected.
[0154] The washed catalyst is preferably then dried. Regarding the
drying conditions, the drying temperature is preferably from 50 to
200.degree. C. and the drying time is preferably from 1 to 10
hours.
[0155] The supported ruthenium oxide catalyst produced by the above
steps is highly active, and is very effective for a process for
preparing chlorine by oxidizing hydrogen chloride with oxygen.
[0156] The supported ruthenium oxide catalyst used in the catalyst
(4) of the present invention is a supported ruthenium oxide
catalyst using titanium oxide containing rutile titanium oxide as a
carrier. As the titanium oxide, for example, rutile titanium oxide,
anatase titanium oxide and non-crystal titanium oxide are known.
The titanium oxide containing rutile titanium oxide used in the
present invention refers to one containing a rutile crystal,
wherein a ratio of the rutile crystal to the anatase crystal in the
titanium oxide is measured by X-ray diffraction analysis. The
measuring process will be described in detail hereinafter. When the
chemical composition of the carrier used in the present invention
is composed of titanium oxide alone, the proportion of the rutile
crystal is determined from a ratio of the rutile crystal to the
anatase crystal in the titanium oxide by using X-ray diffraction
analysis. In the present invention, a mixed oxide of the titanium
oxide and other metal oxide is also used. In that case, the
proportion of the rutile crystal is determined by the following
process. The oxide to be mixed with the titanium oxide includes
oxides of elements, and preferred examples thereof include alumina,
zirconium oxide and silica. The proportion of the rutile crystal in
the mixed oxide is also determined from the ratio of the rutile
crystal to the anatase crystal in the titanium oxide by using X-ray
diffraction analysis. It is necessary to contain the rutile
crystal. In this case, the content of the oxide other than the
titanium oxide in the mixed oxide is within a range from 0 to 60%by
weight. Preferred carrier includes titanium oxide which does not
contain a metal oxide other than titanium oxide.
[0157] It is necessary that the titanium oxide contains the rutile
crystal. The proportion of the rutile crystal is preferably not
less than 10%, more preferably not less than 30%, and most
preferably not less than 80%.
[0158] The process for preparing the titanium oxide containing the
rutile crystal includes various processes. In general, the
following processes are exemplified. For example, when using
titanium tetrachloride as a raw material, titanium tetrachloride is
dissolved by adding dropwise in ice-cooled water, and then
neutralized with an aqueous ammonia solution to form titanium
hydroxide (ortho-titanic acid). Thereafter, the formed precipitate
was washed with water to remove a chlorine ion. In that case, when
the temperature on neutralization becomes higher than 20.degree. C.
or the chlorine ion is remained in the titanium oxide after
washing, conversion into a stable rutile crystal is liable to occur
on calcination. When the calcination temperature becomes not less
than 600.degree. C., conversion into rutile occurs (Catalyst
Preparation Chemistry, 1989, page 211, Kodansha). For example, a
reaction gas is prepared by passing an oxygen-nitrogen mixed gas
through a titanium tetrachloride evaporator and the reaction gas is
introduced into areactor. The reaction between titanium
tetrachloride and oxygen starts at a temperature of about
400.degree. C. and titanium dioxide formed by the reaction of a
TiCl.sub.4--O.sub.2 system is mainly an anatase type. However, when
the reaction temperature becomes not less than 900.degree. C.,
formation of a rutile type can be observed (Catalyst Preparation
Chemistry, 1989, page 89, Kodansha). The preparation process
includes, for example, a process of hydrolyzing titanium
tetrachloride in the presence of ammonium sulfate and calcining
(e.g. Shokubai Kougaku Kouza 10, Catalyst Handbook by Element,
1978, page 254, Chijin Shokan) and a process of calcining an
anatase titanium oxide (e.g. Metal Oxide and Mixed Oxide, 1980,
page 107, Kodansha). Furthermore, rutile titanium oxide can be
obtained by a process for hydrolyzing an aqueous solution of
titanium tetrachloride by heating. Rutile titanium oxide is also
formed by previously mixing an aqueous titanium compound solution
of titanium sulfate or titanium chloride with a rutile titanium
oxide powder, hydrolyzing the mixture by heating or using an
alkali, and calcining at low temperature of about 500.degree.
C.
[0159] The process of determining the proportion of the rutile
crystal in the titanium oxide includes a X-ray diffraction analysis
and, as a X-ray source, various X-ray sources can be used. For
example, a K .alpha. ray of copper is used. When using the K
.alpha. ray of copper, the proportion of the rutile crystal and the
proportion of the anatase are respectively determined by using an
intensity of a diffraction peak of 2.theta.=27.5 degree of the
plane (110) and an intensity of a diffraction peak of 2.theta.=25.3
degree of the plane (101). The carrier used in the present
invention is one having a peak intensity of the rutile crystal and
a peak intensity of the anatase crystal, or one having a peak
intensity of the rutile crystal. That is, the carrier has both of a
diffraction peak intensity of the rutile crystal and a diffraction
peak of the anatase crystal, or has only a diffraction peak of the
rutile crystal. Preferred carrier is one wherein a proportion of
the peak intensity of the rutile crystal to the total of the peak
intensity of the rutile crystal and the peak intensity of the
anatase crystal is not less than 10%. Also in the supported
ruthenium oxide catalyst using in the titanium oxide carrier
containing rutile titanium oxide, an amount of an OH group
contained in the carrier is preferably a similar amount to the
catalyst (5) of the present invention. Although the details will be
described with regard as the catalyst (5) of the present invention,
the amount of the OH group of the titanium oxide of the carrier
used in the catalyst is usually from 0.1.times.10.sup.-4 to
30.times.10.sup.-4 (mol/g-carrier), preferably from
0.2.times.10.sup.-4 to 20.times.10.sup.-4 (mol/g-carrier), and more
preferably from 3.0.times.10.sup.-4 to 15.times.10.sup.-4
(mol/g-carrier).
[0160] The supported ruthenium oxide catalyst used in the catalyst
(5) of the present invention is a supported ruthenium oxide
catalyst obtained by the steps which comprises supporting a
ruthenium compound on a carrier, treating the supported one by
using reducing compound or reducing agent in a liquid phase, and
oxidizing the resulted one, wherein titanium oxide containing an OH
group in an amount of 0.1.times.10.sup.-4 to 30.times.10.sup.-4
(mol/g-carrier) per unit weight of a carrier is used as the
carrier. The carrier includes, for example, rutile crystal carrier,
anatase crystal carrier and non-crystal carrier. Preferable
carriers are rutile crystal carrier and anatase crystal carrier,
and more preferable one is rutile crystal carrier. It is generally
known that a hydroxyl group represented by OH, bound to Ti, exists
on the surface of the titanium oxide. The titanium oxide used in
the present invention is one containing an OH group, and the
process of measuring the content of OH group will be described in
detail hereinafter. When the chemical composition of the carrier
used in the present invention is consisting essentially of titanium
oxide alone, it is determined from the content of the OH group in
the titanium oxide. In the present invention, a mixed oxide of the
titanium oxide and other metal oxide is also used. The oxide to be
mixed with the titanium oxide includes oxides of elements, and
preferred examples thereof include alumina, zirconium oxide and
silica. In that case, the content of the oxide other than the
titanium oxide in the mixed oxide is within a range from 0 to 60%
by weight. Also this case, the content of the OH group per unit
weight of the carrier contained in the carrier is determined by the
measuring process which is also described in detail hereinafter.
Preferred carrier is titanium oxide which does not contain the
metal oxide other than the titanium oxide.
[0161] When the content of the OH group of the carrier is large,
the carrier and supported ruthenium oxide may react each other,
resulting in deactivation. On the other hand, when the content of
the OH group of the carrier is small, the activity of the catalyst
is lowered sometimes by sintering of the supported ruthenium oxide
and the other phenomenon
[0162] The process of determining the content of the OH group of
the titanium oxide includes various processes. For example, a
process using a thermogravimetric process (TG) is exemplified. When
using the thermogravimetric process, the temperature is kept
constant and, after removing excess water in a sample, the sample
is heated and the content of the OH group is measured from a weight
loss. According to this process, the amount of the sample is small
and it is difficult to measure with good accuracy. When heat
decomposable impurities exist in the carrier, there is a drawback
that the actual content of the OH group is not determined. When
using the measurement of ignition loss (Igloss) for measuring the
content of the OH group from the weight loss of the sample in the
same manner, the measurement with high accuracy can be conducted if
the amount of the sample is increased. However, an influence of the
heat decomposable impurities is exerted similar to the case of the
thermogravimetric process. Furthermore, there is also a drawback
that the weight loss obtained by the thermogravimetric process and
ignition loss measurement also includes the bulk OH group content
which is not effective on preparation of the catalyst.
[0163] A process using sodium naphthalene is also exemplified.
According to this process, an OH group in a sample is reacted with
sodium naphthalene as a reagent and then the content of the OH
group is measured from the titration amount of sodium naphthalene.
In this case, since a change in concentration of the reagent for
titration and a trace amount of water exert a large influence on
the results, the measuring results are influenced by the storage
state of the reagent. Therefore, it is very difficult to obtain a
value with good accuracy.
[0164] A titration process using an alkyl alkali metal is also
exemplified. The titration process using the alkyl alkali metal
includes a preferable process of suspending a titanium oxide
carrier or a titanium oxide carrier powder in a dehydrated solvent,
adding dropwise an alkyl alkali metal in a nitrogen atmosphere, and
determining the amount of the OH group contained in the titanium
oxide from the amount of hydrocarbon generated. In that case, since
an alkyl alkali metal and water contained in the dehydrated solvent
react each other to generate hydrocarbon, the content of the OH
group in the titanium oxide must be determined by subtracting the
generated amount from the measured value.
[0165] Most preferred process includes a process of suspending a
titanium oxide carrier or a titanium oxide carrier powder in a
dehydrated solvent, adding dropwise methyl lithium in a nitrogen
atmosphere, and determining the amount of the OH group contained in
the titanium oxide from the amount of hydrocarbon generated, and
the content of the OH group in the titanium oxide catalyst which is
used in the claims of the present invention is a value obtained by
this process.
[0166] The measuring procedure includes, for example, the following
process. First, a sample is previously dried in an air atmosphere
at 150.degree. C. for 2 hours and then cooled in a desiccator.
Thereafter, a predetermined amount of the sample is transferred in
a flask whose atmosphere was replaced by nitrogen, and then
suspended in an organic solvent such as dehydrated toluene. The
flask is ice-cooled to inhibit heat generation and, after adding
dropwise methyl lithium from a dropping funnel, the generated gas
is collected and the volume at the measuring temperature is
measured. The content of the OH group thus determined, which is
used in the catalyst, is usually from 0.1.times.10.sup.-4 to
30.times.10.sup.-4 (mol/g-carrier), preferably from
0.2.times.10.sup.-4 to 20.times.10.sup.-4 (mol/g-carrier), and more
preferably from 3.0.times.10.sup.-4 to 15.times.10.sup.-4
(mol/g-carrier).
[0167] The process of adjusting the amount of the OH group
contained in the titanium oxide carrier to a predetermined amount
includes various processes. For example, a calcination temperature
and a calcination time of the carrier are used for adjusting the OH
group of the carrier. The OH group in the titanium oxide carrier is
eliminated by heating, and the content of the OH group can be
controlled by changing the calcination temperature and calcination
time. The calcination temperature of the carrier is usually from
100 to 1000.degree. C., and preferably from 150 to 800.degree. C.
The calcination time of the carrier is usually from 30 minutes to
12 hours. In this case, it is necessary to pay attention to the
point that the surface area of the carrier decreases with the
increase of the calcination temperature or the calcination time.
When the titanium oxide is produced from a gas phase, one having
small content of the OH group can be produced. Furthermore, when
the titanium oxide is produced from an aqueous phase such as
aqueous solution, one having large content of the OH group can be
produced. Furthermore, a process of treating the OH group of the
carrier by using an alkali and a process of reacting the OH group
by using 1,1,1-3,3,3-hexamethyldisilazane are exemplified.
[0168] The present invention relates to a process for producing
chlorine by using the above supported ruthenium oxide catalyst
supported on the carrier. A weight ratio of ruthenium oxide to the
carrier is usually within a range from 0.1/99.9 to 20.0/80.0,
preferably from 0.5/99.5 to 15.0/85.0, and morepreferably from
1.0/99.0 to 15.0/85.0. When the ratio of ruthenium oxide is too
low, the activity is lowered sometimes. On the other hand, when the
ratio of ruthenium oxide is too high, the price of the catalyst
becomes high sometimes. Examples of the ruthenium oxide to be
supported include ruthenium dioxide, ruthenium hydroxide and the
like.
[0169] The process for preparing the supported ruthenium oxide
catalyst by using the above carrier is a process comprising the
steps of supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing, and the step of treating with a
reducing compound or a reducing agent in a liquid phase includes,
for example, a process of treating with a reducing compound or a
reducing agent in a liquid phase which is conducted in the
catalysts (1), (2) and (3) of the present invention, and the
process described below. That is, the process includes a process of
suspending one comprising the already described ruthenium compound
supported on the carrier in an aqueous phase or an organic solvent,
and bubbling hydrogen, a process of treating by using an
organolithium compound such as butyl lithium, or an organosodium
compound or an organopotassium compound in an organic solvent, a
process of treating by using an organoaluminum compound such as
trialkyl aluminum, and a process of treating by using an
organomagnesium compound such as Grignard reagent. Furthermore,
various organometallic compounds can be used and examples thereof
include alkali metal alkoxide such as sodium methoxide; alkali
metal naphthalene compound such as sodium naphthalene; azide
compound such as sodium azide; alkali metal amide compound such as
sodium amide; organocalcium compound; organozinc compound;
organoaluminum alkoxide such as alkyl aluminum alkoxide; organotin
compound; organocopper compound; organoboron compound; boranes such
as borane and diborane; sodium ammonia solution; and carbon
monoxide. Various organic compound can also be used and examples
thereof include diazomethane, hydroquinone and oxalic acid.
[0170] In a process for producing chlorine by oxidizing hydrogen
chloride with oxygen, it is preferable that the catalyst (1), (2)
or (3) is a supported ruthenium oxide catalyst obtained by using
titanium oxide containing not less than 10% by weight of rutile
titanium oxide as a carrier.
[0171] It is more preferable that the catalyst (1), (2) or (3) is a
supported ruthenium oxide catalyst obtained by using titanium oxide
containing not less than 30% by weight of rutile titanium oxide as
a carrier.
[0172] It is preferable that the catalyst (4) or (5) is a supported
ruthenium oxide catalyst obtained by supporting a ruthenium
compound on a carrier, reducing the supported one by using a
reducing hydrogenated compound, and oxidizing.
[0173] It is preferable that the catalyst (4) or (5) is a supported
ruthenium oxide catalyst obtained by supporting a ruthenium
compound on a carrier, treating the supported one by using a
reducing compound, and oxidizing.
[0174] It is preferable that the catalyst (4) or (5) is a supported
ruthenium oxide catalyst obtained by supporting a ruthenium
compound on a carrier, treating the supported one by using an
alkali solution of a reducing compound, and oxidizing.
[0175] Next, catalyst system will be explained bellow. The catalyst
system (6) in the present invention is a catalyst system containing
at least the following component (A) and (B), wherein the content
of the component (B) in the catalyst system is not less than 10% by
weight:
[0176] (A) an active component of catalyst; and
[0177] (B) a compound component wherein thermal conductivity of a
solid phase measured by at least one point within a range from 200
to 500.degree. C. is not less than 4 W/m. .degree. C.;
[0178] The catalyst system in the present invention means any
packing solid capable of forming a catalyst bed layer. For example,
the catalyst includes not only particles containing an active
component of the catalyst, but also particles of an inactive
component containing no catalytic active component. The catalyst
bed layer includes fixed bed and fluidized bed.
[0179] The catalyst in the present invention means a molding and a
powder which contain a catalytic active component and doesn't mean
an inactive molding and an inactive powder included in a catalyst
bed.
[0180] As the above active component of the catalyst as the
component (A) in the present invention, for example, copper,
chromium, ruthenium, and a compound thereof are known.
[0181] The content of the component (A) in the catalyst is
preferably from 0.1 to 90% by weight, and more preferably from 0.2
to 80% by weight. When the content of the component (A) is too
small, the activity of the catalyst may be lowered. On the other
hand, when the content of the component (A) is too large, the cost
of the catalyst may become high.
[0182] The example of the above active component of catalyst (A)
include ruthenium compound. When using a ruthenium compound, a
catalyst having high activity can be prepared, so the ruthenium
compound is preferable. The more preferable example include
ruthenium oxide. A catalyst having higher activity can be prepared
by using ruthenium oxide.
[0183] In the view of the catalyst activity, it is preferable that
a component (A) is a component supported on the catalyst carrier
component or a component (B). For example, in the case of a
component (A) is an expensive noble metal compound such as
ruthenium, large effects can be realized in the cost of the
catalyst by supporting a component (A) on the catalyst carrier
component or the component (B) because the catalyst activity
increases by supporting a small amount of noble metal.
[0184] More preferable example includes supported ruthenium oxide
catalyst on the catalyst carrier component or the component
(B).
[0185] The component (B) in the present invention is a compound
wherein thermal conductivity of a solid phase measured by at least
one point within a range from 200 to 500.degree. C. is not less
than 4 W/m. .degree. C.
[0186] The thermal conductivity of compounds of the solid phase in
the present invention means the thermal conductivity measured in
the state of continuum (continuous phase) such as a crystal, an
amorphous solid, a glass. For example, in the case of the compound
is a crystal, thermal conductivity is measured in the phase of
crystal solid.
[0187] The thermal conductivity of the solid phase is described,
for example, in Latest Oxide Handbook-Physiochemical Properties-,
(published by Moscow Metallurgical Publication, 1978),
Thermophysical PROPERTIES of High Temperature Solid Metals (Oxides
and Their Solutions and Mixtures) (published by The Macmillan
Company, 1967).
[0188] The thermal conductivity of the solid phase is preferably
higher. It is necessary not less than 4 W/m. .degree. C. And it is
further preferably not less than 15 W/m. .degree. C.
[0189] Preferred example of the component (B) includes
.alpha.-alumina, rutile tin dioxide, rutile titanium oxide, silicon
nitride and silicon carbide. More preferred one is .alpha.-alumina.
When an inactive component is added, the activity of the catalyst
is sometimes lowered. However, by selecting an additive capable of
improving the thermal conductibility with maintaining the activity
of the catalyst, the reaction can be conducted in more industrially
advantageous manner. Since the thermal conductibility can be
improved with maintaining the activity of the catalyst by adding
.alpha.-alumina, preferred example of the component (B) in view of
the activity of the catalyst includes .alpha.-alumina.
[0190] It is necessary the content of the component (B) is not less
than 10% by weight, and preferably not less than 20% by weight.
[0191] By using a catalyst containing not less than 10% by weight
of the component (B), the reaction heat is sufficiently removed,
thereby making it easy to control the reaction temperature. Since
the whole catalyst bed can be utilized at the temperature capable
of oxidizing hydrogen chloride at an industrially sufficient
reaction rate, high reaction conversion can be realized.
[0192] The catalyst carrier component in the present invention is
as follows. The examples thereof include oxides and mixed oxides of
elements, such as titanium oxide, alumina, zirconium oxide, silica,
titanium mixed oxide, zirconium mixed oxide, aluminum mixed oxide,
silicon mixed oxide and the like. Titanium oxide is the most
preferable catalyst carrier component among the above example
because the catalyst has high catalytic activity by using a
ruthenium compound as an active component of catalyst (A)
[0193] When a catalyst carrier component is a compound wherein
thermal conductivity of a solid phase measured by at least one
point with in a range from 200 to 500.degree. C. is not less than 4
W/m. .degree. C., the above catalyst carrier component is regarded
as a component (B). For example, in the case of titanium oxide,
there exists rutil crystal titanium oxide, anatase crystal titanium
oxide, etc. As thermal conductivity of rutil titanium oxide of a
solid phase measured at 200.degree. C. is 7.5 W/m. .degree. C.,
rutil titanium oxide is regarded as a component (B). And in the
case of alumina, there exists .alpha.-alumina, .gamma.-alumina,
etc. As thermal conductivity of .alpha.-alumina of a solid phase
measured at 200.degree. C. is 23 W/m. .degree. C., .alpha.-alumina
is regarded as a component (B). As rutil titanium oxide,
.alpha.-alumina, etc wherein thermal conductivity of the catalyst
carrier component is not less than 4 W/m. .degree. C. at
200.degree. C. in the solid phase, they are regarded as a component
(B). However, as the thermal conductivity of zirconium oxide of a
solid phase measured at 400.degree. C. is 2.05 W/m. .degree. C.,
zirconium oxide is not regarded as a component (B). Therefore the
catalyst carrier component includes a part of component (B). On the
contrary, for example, in the case of silicon nitride, the thermal
conductivity of a solid phase measured at 200.degree. C. is 24 W/m.
.degree. C., so it is regarded as a component (B), but it is not
regarded as a catalyst carrier component because silicon nitride
has too small surface area to support an active component of
catalyst (A). Therefor, among the component (B), the component
which can't support an active component (A) is not a catalyst
carrier component. As mentioned above, the catalyst carrier
component include a part of component (B).
[0194] The catalyst system in the present invention contains not
less than 10% by weight of a component (B) because the thermal
conductibility improve by containing the componennt (B). The
catalyst system preferably contains not less than 20% by weight of
a component (B) because the thermal conductibility can be much
improved.
[0195] Examples of the shape of the carrier of the catalyst in the
case of supporting the active component of the catalyst includes
powder, sphere, column, extruded shape and those obtained by spray
drying process. In the case of the powder, a process of using the
powder after molding into sphere, column, extruded shape and the
like is generally used so as to use the powder industrially.
[0196] Next the catalyst system which contains the component (B) in
the present invention will be explained. The catalyst system
comprises two components such as the component (A) and the
component (B), or comprises three components such as the component
(A), the component (B) and the catalyst carrier component. And the
catalyst system can contain the other component such as an
inorganic binder which is used for a molding aid.
[0197] First embodiment includes a process of using a catalyst made
of a molding containing the components (A) and (B) obtained by
integrally molding. For example, the catalyst preparation includes
the steps which comprises mixing an active component of catalyst
(A) with component (B), molding the components by using an
inorganic binder, and calcining. The resulting catalyst is
preferable catalyst being easily charged in a reactor because of
integrally molding.
[0198] The process of using a catalyst made of a molding containing
the component (A), the component (B) and catalyst carrier component
obtained by integrally molding is exemplified. For example, the
catalyst preparation method includes the steps which comprises
mixing an active component (A) with fine particle of catalyst
carrier component resulted in high surface area catalyst, mixing
the resulted one with component (B), molding the component by using
inorganic binder, and calcining. The resulting catalyst is
preferable as the catalyst is molded integrally and the catalytic
activity is improved.
[0199] The catalyst made of a molding containing the component (A)
supported on a component (B) is exemplified. The catalyst
preparation method include the steps which comprises supporting a
component (A) on a component (B) which have high surface area,
wherein a supported one has high catalytic activity , molding the
resulted one by using inorganic binder, and calcining. The
resulting catalyst is preferable as the catalyst has high activity,
good thermal conductibility, and easily charges into a reactor
because of integrally molding.
[0200] The catalyst made of a molding containing a component (A)
supported on a catalyst carrier component and component (B) is
exemplified. The catalyst preparation method includes the steps
which comprises supporting a component (A) on a catalyst carrier
component having high surface area, mixing the resulted one with
component (B), molding the mixed one by using inorganic binder
integrally, and calcining. The resulting catalyst is more
preferable as the catalyst has high catalytic activity, good
thermal conductibility.
[0201] The catalyst made of a molding containing a component (A)
supported on a mixture of a catalyst carrier component with a
component (B) is exemplified. The catalyst preparation method
includes the steps which comprises mixing catalyst carrier
component with a component (B), molding the resulted one by using
inorganic binder integrally, calcining the molded one, and
supporting a component (A) on the calcined one. The resulting
catalyst is more preferable as the catalyst has high catalytic
activity, good thermal conductibility.
[0202] A second embodiment includes a process using a catalyst
system comprising both of a molding containing the component (A)
and (B) obtained by integrally molding and a molding containing the
component (B) obtained by integrally molding. For example, the
catalyst system is a mixture of the two moldings. The preparation
method of one molding of the catalyst includes the steps which
comprises mixing a component (A) with a component (B), molding the
components by using inorganic binder integrally, calcining. The
preparation method of another molding includes the steps which
comprises molding the component (B) by using inorganic binder
integrally, calcining. The resulting catalyst system is preferable
as the catalyst system shows good thermal conductibility. The
molding containing a component (A) and a component (B) integrally
is exemplified in the first embodiment.
[0203] The method includes a process of using a catalyst system
comprising both of a molding containing a component (A) and
catalyst carrier component obtained by integrally molding and a
molding containing a component (B) obtained by integrally molding.
One example of the catalyst system is a mixture of the two
moldings. The preparation method of one molding of the catalyst
includes the steps which comprises supporting a component (A) on a
catalyst carrier component, molding the supported one by using
inorganic binder integrally, calcining. The preparation of another
molding include the steps which comprises molding a component (B)
by using inorganic binder integrally, calcining. The another
example of the catalyst system is a mixture of the two moldings.
The preparation method of one molding of the catalyst includes the
steps which comprises molding a catalyst carrier component by using
inorganic binder integrally, calcining the molded one, supporting a
component on the calcined one. The preparation method of another
one includes the steps which comprises molding a component (B) by
using inorganic binder integrally, calcining. The two examples of
the catalyst systems are preferable examples respectively as the
catalyst systems show high catalytic activity, and good thermal
conductibility. Generally the catalyst system obtained by mixing
the sphere molding of .alpha.-alumina with the sphere molding which
comprises a component (A), a catalyst carrier component is more
preferable as the catalyst system has good thermal
conductibility.
[0204] Among the above catalysts, a preferable one is a catalyst
which the component (C) is .alpha.-alumina.
[0205] Among the above catalysts, preferable one is a catalyst
which the component (A) is a component containing ruthenium. More
preferable one is a catalyst which the component (A) is ruthenium
oxide.
[0206] Among the above catalysts, preferable one is a catalyst
which the carrier of the catalyst is titanium oxide.
[0207] The catalyst used in the present invention is a catalyst
capable of producing chlorine by oxidizing hydrogen chloride with
oxygen. Preferable catalyst includes, for example, catalyst
containing copper as an active component of the catalyst, such as
Deacon catalyst; catalyst containing chromium as an active
component of the catalyst, such as chromia-silica catalyst; and
catalyst containing ruthenium as an active component of the
catalyst. More preferable catalyst is a catalyst containing
ruthenium. Since ruthenium is expensive, a catalyst containing a
supported ruthenium catalyst supported on the carrier of the
catalyst is a more preferable catalyst.
[0208] The supported ruthenium catalyst includes, for example,
supported ruthenium oxide catalyst, supported metal ruthenium
catalyst, and catalyst obtained by supporting a ruthenium
compound.
[0209] As the supported ruthenium catalyst, a supported ruthenium
oxide catalyst is preferred because high activity can be obtained
by low Ru content. The carrier of the supported ruthenium catalyst
includes oxides and mixed oxides of elements, such as titanium
oxide, alumina, zirconium oxide, silica, titanium mixed oxide,
zirconium mixed oxide, aluminum mixed oxide, silicon mixed oxide
and the like. Preferable catalyst carrier components are titanium
oxide, alumina, zirconium oxide and silica, and more preferable
catalyst carrier component is titanium oxide, and most preferable
carrier is titanium oxide having rutile crystalline structure.
[0210] The supported ruthenium oxide catalyst will be explained
below. A weight ratio of ruthenium oxide to the carrier of the
catalyst is usually within a range from 0.1/99.9 to 20.0/80.0,
preferably from 0.2/99.8 to 15.0/85.0, and more preferably from
0.5/99.5 to 10.0/90.0. When the proportion of the ruthenium oxide
is too low, the activity is lowered sometimes. On the other hand,
when the proportion of ruthenium oxide is too high, the price of
the catalyst becomes high sometimes. Examples of the ruthenium
oxide to be supported include ruthenium dioxide, ruthenium
hydroxide and the like.
[0211] The process of preparing a supported ruthenium oxide will be
explained below.
[0212] The process of preparing a catalyst includes various
processes, and four kinds of preparation process will be shown as
an embodiment. A catalyst having high thermal conductibility can be
used in the present invention, and a process of increasing the
thermal conductibility of the catalyst includes a process for
preparing a catalyst by mixing a compound having high thermal
conductivity. Examples of the component (B) having high thermal
conductivity includes various compounds, but a process using
.alpha.-alumina is exemplified. The catalyst carrier component
includes various compounds , but the embodiment using titanium
oxide is exemplified. The catalyst is prepared by supporting a
ruthenium compound on the catalyst carrier component but the
ruthenium compound to be supported varies depending on the
preparation process. Now the embodiment using ruthenium chloride is
exemplified.
[0213] The first embodiment of four kinds of the preparation
processes is a process which comprises uniformly mixing a titanium
oxide powder with an .alpha.-alumina powder, adding a titanium
oxide sol, and molding a carrier of a catalyst. The proportion of
the titanium oxide sol to be mixed is preferably within a range
from 3 to 30% by weight in terms of titanium oxide in the titanium
oxide sol, based on the weight of the titanium oxide and
.alpha.-alumina. The molding process includes process of molding
into a spherical shape and a process of extrusion molding. The
molded object is dried and then calcined under air to prepare a
carrier of a catalyst. The calcination temperature is preferably
within a range from 300 to 800.degree. C. At this stage, a carrier
having high thermal conductibility can be obtained. Then, an
aqueous solution of ruthenium chloride is supported by
impregnation. The amount of ruthenium chloride to be used
corresponds to a preferable ratio of the ruthenium oxide to the
carrier of the catalyst. Then, the supported one is dried. A
supported ruthenium oxide catalyst is prepared by reducing the
dried one with a reducing hydrogenated compound such as sodium
boron hydride, and oxidizing, or prepared by treating the dried one
with a reducing compound such as hydrazine, and oxidizing. The
preparation process will be explained in detail hereinafter.
[0214] The second embodiment of four kinds of the preparation
processes is a process which comprises uniformly mixing a titanium
oxide powder with an .alpha.-alumina powder, and supporting an
aqueous ruthenium chloride by impregnation. The amount of the
ruthenium chloride to be used corresponds to a preferable ratio of
the ruthenium oxide to the carrier of the catalyst. Then, the
supported one is dried. The dried one is reduced with a reducing
hydrogenated compound such as sodium boron hydride or treated with
a reducing compound such as hydrazine. The preparation process will
be explained in detail hereinafter. Then, a titanium oxide sol is
added and a carrier of the catalyst is molded. The proportion of
the titanium oxide sol is the same proportion as that shown in the
first embodiment. Then, a catalyst is prepared by drying the molded
one, calcining under air to oxidize ruthenium, and washing with
water in the same manner as the process of preparing the supported
ruthenium oxide catalyst, which will be explained in detail
hereinafter. At this stage, a catalyst having good thermal
conductibility can be obtained.
[0215] The third embodiment of four kinds of the preparation
processes is a process which comprises supporting an aqueous
solution of ruthenium chloride on a powder of titanium oxide by
impregnation. The amount of the ruthenium chloride to be used
corresponds to a preferable ratio of the ruthenium oxide to the
carrier of the catalyst. Then, the supported one is dried. The
dried one is reduced with a reducing hydrogenated compound such as
sodium boron hydride or treated with a reducing compound such as
hydrazine. The preparation process will be explained in detail
hereinafter. Then, .alpha.-alumina is uniformly mixed. Then, a
titanium oxide sol is added and a carrier of the catalyst is
molded. The proportion of the titanium oxide sol is the same
proportion as that shown in the first embodiment. Then, a catalyst
is prepared by drying the molded one, calcining under air to
oxidize ruthenium, and washing with water in the same manner as the
process of preparing the supported ruthenium oxide catalyst, which
will be explained in detail hereinafter. At this stage, a catalyst
having good thermal conductibility can be obtained.
[0216] The fourth embodiment of four kinds of the preparation
processes is a process which comprises supporting an aqueous
solution of ruthenium chloride on a powder of titanium oxide by
impregnation. The amount of the ruthenium chloride to be used
corresponds to a preferable ratio of the ruthenium oxide to the
carrier of the catalyst. Then, the supported one is dried. The
dried one is reduced with a reducing hydrogenated compound such as
sodium boron hydride and then oxidized to prepare a supported
ruthenium oxide catalyst. Alternatively, the dried one is treated
with a reducing compound such as hydazine and then oxidized to
prepare a supported ruthenium oxide catalyst. The preparation
process will be explained in detail hereinafter. Then,
.alpha.-alumina is uniformly mixed. Then, a titanium oxide sol is
added and a carrier of the catalyst is molded. The proportion of
the titanium oxide sol is the same proportion as that shown in the
first embodiment. Then, the molded one is dried and then calcined
under air. The calcination temperature is preferably within a range
from 300 to 600.degree. C. Then, the calcined one is washed with
water to prepare a catalyst. At this stage, a catalyst having good
thermal conductibility can be obtained.
[0217] The process for preparing a supported ruthenium oxide
catalyst used in the present invention includes a process for
preparing a supported ruthenium oxide catalyst by supporting a
ruthenium compound on a carrier of a catalyst, reducing the
supported one by using a reducing hydrogenated compound such as
sodium boron hydride, and oxidizing, or a process for preparing a
supported ruthenium oxide catalyst by treating a ruthenium compound
by using a reducing compound such as hydrazine, and oxidizing, for
example, processes for preparing the catalysts (1), (2) and (3) of
the present invention.
[0218] The first embodiment of the process for preparing a
supported ruthenium oxide catalyst used in the present invention
includes a process for preparing a supported ruthenium oxide
catalyst by reducing a ruthenium compound supported on a carrier of
a catalyst by using a reducing hydrogenated compound, and
oxidizing.
[0219] The ruthenium compound to be supported on the carrier of the
catalyst includes the same compounds as those listed with respect
to the catalysts (1), (2) and (3) of the present invention.
[0220] The reducing hydrogenated compound used for reducing the
ruthenium compound supported on the carrier of the catalyst
includes the same compounds as those listed with respect to the
catalyst (3) of the present invention.
[0221] The second embodiment of the process for preparing a
supported ruthenium oxide catalyst used in the present invention
includes a process for preparing a supported ruthenium oxide
catalyst by reducing a ruthenium compound supported on a carrier of
a catalyst by using a reducing compound, and oxidizing.
[0222] The ruthenium compound to be supported on the carrier of the
catalyst includes the same compounds as those listed with respect
to the catalysts (1), (2) and (3) of the present invention.
[0223] The reducing compound used for treating the ruthenium
compound supported on the carrier of the catalyst includes the same
compounds as those listed with respect to the catalysts (1) and (2)
of the present invention.
[0224] The process for preparing a supported metal ruthenium
catalyst will be explained below. The first embodiment of the
process for preparing the supported ruthenium oxide catalyst was
mentioned after the four embodiment of the process for preparing
the catalyst having good thermal conductibility.
[0225] The supported metal ruthenium catalyst includes, for
example, supported metal ruthenium catalyst obtained by supporting
a ruthenium compound shown in the first embodiment of the process
for preparing the supported ruthenium oxide on the above-described
carrier in the same manner, and reducing the supported one to form
metal ruthenium by using a reducing agent, for example, a reducing
hydrogenated compound such as sodium boron hydrate shown in the
first embodiment of the process for preparing the supported
ruthenium oxide catalyst, and supported metal ruthenium catalyst
obtained by supporting ruthenium chloride on the above-described
carrier, forming a ruthenium hydroxide on the carrier by alkali
hydrolysis, and reducing the ruthenium hydroxide by using hydrogen,
but a commercially available Ru catalyst may also be used. A ratio
of the metal ruthenium to the carrier in the metal ruthenium
supported on the carrier is usually from 0.1/99.9 to 20/80, and
preferably from 1/99 to 10/90. When the amount of the metal
ruthenium is too small, the activity of the catalyst is lowered. On
the other hand, when the amount of the metal ruthenium oxide is too
large, the price of the catalyst becomes high.
[0226] The process for preparing a catalyst comprising a supported
ruthenium compound will be explained.
[0227] The catalyst comprising a supported ruthenium compound
includes the same compounds as those exemplified in the catalysts
(1), (2) and (3) of the present invention.
[0228] The supporting process includes impregnation process, ion
exchange process, precipitation supporting process, coprecipitation
process and mixing process. Among them, impregnation process and
ion exchange process are preferred.
[0229] The impregnation process includes, for example, a
preparation process of suspending a carrier in a solution prepared
by dissolving a ruthenium compound, evaporating a solvent, and
drying. The solvent includes water, methanol and organic solvent,
etc.
[0230] When the drying temperature of the supported catalyst is too
high, volatilization of the ruthenium compound occurs and,
therefore, the drying temperature is preferably from 30 to
200.degree. C. under reduced pressure, and is preferably from about
60 to 400.degree. C. under nitrogen. Under air, the drying
temperature is generally a temperature at which the ruthenium
compound is not decomposed by oxidation with oxygen. The drying
time is preferably from about 30 minutes to 5 hours.
[0231] In a catalyst using a catalyst containing a molding obtained
by integrally molding (A) an active component of catalyst and a
catalyst carrier component, and (B) a compound wherein thermal
conductivity of a solid phase measured by at least one point within
a range from 200 to 500.degree. C. is not less than 4 W/m. .degree.
C., the inventors have succeeded in preparation of a catalyst
having almost the same activity of the catalyst prepared from the
component (A) and a catalyst carrier component as a catalyst which
is obtained by integrally molding three components, a component
(A), a catalyst carrier component and a component (B).
[0232] It is an object of the present invention to obtain chlorine
by oxidizing hydrogen chloride with oxygen using the above catalyst
system. When hydrogen chloride is oxidized with oxygen using the
above catalyst, a removing rate of heat generated during the
reaction increases and, therefore, control of the reaction
temperature becomes easier and high reaction conversion can be
obtained by keeping the whole catalyst bed at sufficient
temperature for an industrially desirable reaction rate. The
reaction system for producing chlorine includes, for example, a
flow system such as fixed bed or fluidized bed, and a gas phase
reaction such as fixed bed flow system and gas phase fluidized bed
flow system can be preferably used. The fixed bed system has an
advantage that separation between the reaction gas and catalyst is
not required and high conversion can be accomplished. In the case
of the fixed bed reactor, a reaction tube is packed with catalyst
particles and, in the case of the exothermic reaction, the reaction
tube is cooled from the outside. In such a packed bed, since
effective thermal conductivity of the particle bed is generally
smaller than that of a tube material and that of a fluid outside
the tube and heat transfer resistance in the particle bed is
generally larger than that of a tube material and that of a fluid
outside the tube, the whole heat transfer rate can be markedly
improved by increasing effective thermal conductivity in the
particle bed. The term "effective thermal conductivity of the
particle bed" used herein means a heat transfer rate per unit
sectional area of the particle bed in a certain direction per unit
length and per unit degree of difference which is 1.degree. C.
temperature. According to "Thermal Unit Operation, Vol. 1" (1976,
page 136.about.146, Maruzen Co., Ltd.), it is known that effective
thermal conductivity of the particle bed depends on effective
thermal conductivity of particles to be packed and thermal
conductivity of a fluid material existing in the tube, and depends
on a fluid velocity when the fluid transfers. Among them, effective
thermal conductivity of particles strongly depends on the thermal
conductivity of the solid of the component (compound) constituting
the particles and, therefore, effective thermal conductivity of the
particles and effective thermal conductivity of the particle bed
are increased by using the component having large thermal
conductivity, and contribute to an improvement in removing rate of
heat generated in the reactor in the exothermic reaction such as
oxidation reaction of hydrogen chloride. As described above, the
effect of the present invention is particularly large when the
fixed bed system is adopted. The fluidized bed system has an
advantage that heat transfer in the reactor is large and the
temperature distribution width in the reactor can be minimized. The
temperature distribution width can be further minimized by using
the catalyst according to the present invention.
[0233] By using the catalyst which has good thermal conductibility
(heat transfer) and is capable of easily removing heat, the above
effect can be obtained without increasing the heat transfer area
per unit volume in the reactor. For example, comparing a multitube
reactors having the same reaction volumes, when the heat transfer
area is increased by decreasing the diameter of the tube, the
number of required tubes and amount of the required material are
increased and the price of the reactor becomes high. However, when
using the catalyst which has good thermal conductibility (heat
transfer) and is capable of easily remove heat, control of the
reaction temperature can be made easier without increasing the heat
transfer area of the reactor and the reactor with cheap price can
be used. Therefore, it is industrially advantageous.
[0234] The supported ruthenium oxide catalyst containing macropores
having a pore diameter of 0.03 to 8 micrometer used in the catalyst
(7) of the present invention is a catalyst containing a supported
ruthenium oxide catalyst comprising ruthenium oxide supported on a
carrier. In general, it is industrially used in the form of being
supported on the carrier.
[0235] The carrier includes oxides and mixed oxides of elements,
such as titanium oxide, alumina, zirconium oxide, silica, titanium
mixed oxide, zirconium mixed oxide, aluminum mixed oxide, silicon
mixed oxide and the like. Preferable carriers are titanium oxide,
alumina, zirconium oxide and silica, and more preferable carrier is
titanium oxide. A weight ratio of ruthenium oxide to the carrier is
usually within a range from 0.1/99.9 to 20.0/80.0, preferably from
0.5/99.5 to 15.0/85.0, and more preferably from 1.0/99.0 to
15.0/85.0. When the proportion of the ruthenium oxide is too low,
the activity is lowered sometimes. On the other hand, when the
proportion of ruthenium oxide is too high, the price of the
catalyst becomes high sometimes. Examples of the ruthenium oxide to
be supported include ruthenium dioxide, ruthenium hydroxide and the
like.
[0236] The embodiment of the process for preparing the catalyst
containing macropores having a pore diameter of 0.03 to 8
micrometer will be described below. The catalyst is prepared by
mixing a carrier powder of titanium oxide with an organic material
for forming pores or an inorganic material for forming pores.
First, the case using the organic material for forming pores will
be illustrated. The organic material for forming pores includes
celluloses such as crystalline cellulose, fibrous cellulose, filter
paper and pulp. Fibrous celluloses such as filter paper and pulp
are preferred. After adding water to a carrier powder of titanium
oxide and kneading, the organic material for forming pores such as
cellulose is added and the mixture is sufficiently kneaded. Then,
binders such as titania sol, silica sol and alumina sol may also be
added or not. Binders are preferably added. Among sols, titania sol
is preferred. After the sol is added and kneading, the kneaded one
is extruded and molded into one having a suitable size using a
molding machine, such as a extruder. After the molded one is dried,
the dried one is calcined to remove the organic material for
forming pores such as cellulose. The calcination temperature is
preferably from 400 to 700.degree. C., and more preferably from 500
to 600.degree. C. By calcining the carrier under air, the organic
material for forming pores can be removed by burning, thereby to
form pores having a pore diameter of 0.03 to 8 micrometer in the
carrier. A weight ratio of the organic material for forming pores
such as cellulose to the carrier powder is usually from 1/99 to
40/60, and preferably from 5/95 to 30/70. A weight ratio of
titania, silica and alumina contained in titania sol, silica sol
and alumina sol to the carrier powder is usually from 5/95 to
40/60, and preferably from 10/90 to 30/70.
[0237] Then, the case using the inorganic material for forming
pores will be illustrated. The inorganic material for forming pores
includes alkali metal salts such as sodium chloride and potassium
chloride; alkali metal sulfates such as sodium sulfate and
potassium sulfate; and high-melting point inorganic salts such as
potassium nitrate. Chlorides of alkali metals are preferred, and
potassium chloride and sodium chloride are more preferred. After
adding water to a carrier powder such as titanium oxide and
kneading, an aqueous solution of the inorganic material for forming
pores such as potassium chloride is added and the mixture is
sufficiently kneaded. Then, binders such as titania sol, silica sol
and alumina sol may also be added. Binders are preferably added.
Among sols, titania sol is preferred. After the sol is added and
kneading, the kneaded one is extruded and molded into one having a
suitable size using a molding machine, for example a extruder. The
molded one is dried. After drying, the dried one is sintered by
calcining. The calcination atmosphere includes air and nitrogen,
and air is preferred. The calcination temperature is preferably
from 400 to 700.degree. C., and more preferably from 500 to
600.degree. C. After cooling to room temperature, the inorganic
salt contained in the carrier can be removed by sufficiently
washing the carrier with water. The process of confirming that
potassium chloride and sodium chloride could be removed includes a
process of examining the presence/absence of white turbidity using
an aqueous silver nitrate solution. By drying the carrier after
washing with water, micropores having a diameter of 0.01 to 0.4
micrometer can be formed in the carrier. A weight ratio of the
inorganic material for forming pores such as inorganic salt to the
carrier powder is usually from 5/95 to 40/60, and preferably from
5/95 to 30/70. A weight ratio of titania, silica and alumina
contained in titania sol, silica sol and alumina sol to the carrier
powder is usually from 5/95 to 40/60, and preferably from 5/95 to
30/70. The carrier having micropores can be prepared in the above
manner.
[0238] Among the above-mentioned organic material for forming pores
and inorganic material for forming pores organic material for
forming pores is preferable.
[0239] The embodiment of the process for preparing the supported
ruthenium oxide catalyst is as follows. The preparation of the
supported ruthenium oxide catalyst containing macropores having a
pore diameter of 0.03 to 8 micrometer is conducted in the same
manner as that in process for preparing the catalyst, which is
conducted in the catalysts (1), (2) and (3) of the present
invention using a carrier prepared in the preparation examples of
the already described carrier containing micropores.
[0240] The catalyst (7) of the present invention is characterized
by using a supported ruthenium oxide catalyst containing macropores
having a pore diameter of 0.03 to 8 micrometer, and the pore
diameter distribution of macropores can be measured by a mercury
porosimeter. The exist of many pores is preferable. The pore
diameter of macropores, which can be formed by the process
described above, is usually from 0.03 to 8 micrometer, and more
preferably from 0.03 to 6 micrometer. The larger pore volume of
macropores is preferable. The supported ruthenium oxide catalyst
containing macropores is preferably a catalyst wherein a ratio of
an accumulated pore volume of 0.03-6 micrometer to an accumulated
pore volume of 30-200 angstroms is not less than 0.2/1.0, and
preferably not less than 0.29/1.0. Since the pore diameter of the
carrier does not change largely by supporting of the ruthenium
compound, the pore diameter of the catalyst can be determined by
measuring the pore diameter of the carrier.
[0241] As the catalyst (8) of the present invention, an outer
surface-supported catalyst obtained by supporting ruthenium oxide
on a carrier at the outer surface can also be used. The supported
ruthenium oxide catalyst used in the present invention is a
catalyst wherein the same content as that of ruthenium oxide
described in the item of the supported ruthenium oxide containing
macropores is used and the same carrier is preferably used, that
is, a supported ruthenium oxide catalyst obtained by supporting
ruthenium oxide on a carrier. In general, it is industrially used
in the form of being supported on the carrier.
[0242] The carrier includes oxides and mixed oxides of elements,
such as titanium oxide, alumina, zirconium oxide, silica, titanium
mixed oxide, zirconium mixed oxide, aluminum mixed oxide, silicon
mixed oxide and the like. Preferable carriers are titanium oxide,
alumina, zirconium oxide and silica, and more preferable carrier is
titanium oxide. A weight ratio of ruthenium oxide to the carrier is
usually within a range from 0.1/99.9 to 20.0/80.0, preferably from
0.5/99.5 to 15.0/85.0, and more preferably from 1.0/99.0 to
15.0/85.0. When the proportion of the ruthenium oxide is too low,
the activity is lowered sometimes. On the other hand, when the
proportion of ruthenium oxide is too high, the price of the
catalyst becomes high sometimes. Examples of the ruthenium oxide to
be supported include ruthenium dioxide, ruthenium hydroxide and the
like.
[0243] The process of supporting ruthenium oxide on a carrier at
the outer surface includes various processes. For example, when a
.gamma.-alumina carrier is impregnated with ruthenium chloride, it
is supported at the outer surface and, therefore, it is
comparatively easy to prepare a catalyst wherein ruthenium oxide is
supported at the outer surface. However, when a carrier such as
titanium oxide is impregnated with ruthenium chloride, it
penetrates into the inside of the carrier and, therefore, it is not
easy to support the carrier at the outer surface. Therefore, as the
process of supporting ruthenium oxide on a carrier at the outer
surface, various processes have been suggested. For example, a
process of supporting ruthenium chloride on a carrier by spraying
is illustrated. As the process of supporting ruthenium oxide on a
carrier of titanium oxide at the outer surface, any known process
may be used. The present inventors have found that ruthenium
chloride can be satisfactorily supported on a carrier at the outer
surface by using an alkali preliminary impregnation process
described below. The procedure will be explained by way of the
preparation example. That is, first, a carrier of titanium oxide
having a suitable particle diameter is impregnated with an aqueous
solution of an alkali metal hydroxide such as potassium hydroxide
and a solution of alkali such as ammonium carbonate and ammonium
hydrogencarbonate. In this case, a thickness of a layer of
ruthenium chloride at the surface to be supported on the carrier is
determined by changing the kind of the alkali, concentration of the
alkali, amount of ruthenium chloride to be supported, and time from
impregnation with ruthenium chloride to drying. For example, when
using potassium hydroxide, a thickness of a layer to be impregnated
with ruthenium chloride can be changed by changing the
concentration of the aqueous solution of potassium hydroxide within
a range from 0.1 N to 2.0 N. Then, the carrier is impregnated with
an aqueous solution of an alkali, and the carrier is dried. Then,
the carrier is impregnated with a solution of ruthenium chloride
and the carrier is dried. As the solution, an aqueous solution, a
solution of an organic solvent such as alcohol, or a mixed solution
of water and an organic solvent is used, and a solution of an
organic solvent such as ethanol is preferred. Then, the carrier
impregnated with ruthenium chloride is dried and hydrolyzed by
using an alkali to form ruthenium hydroxide, which is converted
into ruthenium oxide. Alternatively, the supported ruthenium
chloride is reduced to form metal ruthenium, which is oxidized to
form ruthenium oxide. The process for preparing the supported
ruthenium oxide catalyst includes the following process.
[0244] That is, the process of supporting ruthenium chloride on a
carrier at the outer surface was described above, the embodiment of
the preparation process of converting one supporting ruthenium
chloride into a supported ruthenium oxide catalyst is described as
follows. By using the already described one obtained by supporting
ruthenium chloride on a carrier at the outer surface, the process
is conducted in the same manner as that in the process for
preparing a catalyst conducted in the catalysts (1), (2) and (3) of
the present invention.
[0245] The catalyst comprising ruthenium oxide supported on a
carrier at the outer surface can be prepared in the above
manner.
[0246] The alkali used in the step of preliminarily impregnating
the carrier with an aqueous solution of an alkali preferably
includes potassium hydroxide, sodium hydroxide, ammonium carbonate
and ammonium hydrogencarbonate. The concentration of the alkali
impregnated in the carrier is usually from 0.01 to 4.0 N, and
preferably from 0.1 to 3.0 N. When the time from impregnation of
ruthenium chloride on the carrier, which is impregnated
preliminarily with the alkali, to drying is long, the inside of the
carrier is also impregnated with ruthenium chloride and, therefore,
a suitable time must be selected according to the kind and
concentration of the alkali to be used. Usually, the catalyst is
dried immediately after impregnation, or dried until 120 minutes
after impregnation. Preferably, the catalyst is dried immediately
after impregnation, or dried until 30 minutes after
impregnation.
[0247] The catalyst of the present invention is an outer
surface-supported catalyst obtained by supporting ruthenium oxide
on a carrier at the outer surface, and the thickness of the layer
for supporting ruthenium oxide is preferably less than 70% of a
length from the surface of the carrier as a base point to the
center of the carrier particles, and more preferably less than 60%
of a length from the surface of the carrier as a base point to the
center of the carrier particle. The process of measuring the
thickness of the layer for supporting ruthenium oxide includes a
process of cutting along the plane passing through the center of
the particles of the supported ruthenium oxide catalyst and
measuring by using a magnifying glass having graduation , and a
process of cutting in the same manner and measuring by using X-ray
microanalyser (EPMA). Since the ruthenium component is fixed to the
carrier by impregnating the carrier with ruthenium chloride and
drying, the ruthenium component does not transfer largely in the
step of preparing the catalyst. Therefore, the thickness of the
ruthenium oxide layer is determined by measuring the thickness of
the layer supporting ruthenium chloride at the stage where the
catalyst is impregnated and dried.
[0248] As described above, it is also preferable that a process
uses a catalyst obtained by supporting ruthenium oxide on a carrier
containing macropores at the outer surface, wherein said process
combines to use a process for producing chlorine using a supported
ruthenium oxide catalyst containing macropores having a pore
diameter of 0.03 to 8 micrometer as the catalyst (7) with a process
for producing chlorine using an outer surface-supported catalyst
obtained by supporting ruthenium oxide on a carrier as the catalyst
(8) at the outer surface.
[0249] The supported ruthenium catalyst using chromium oxide in the
carrier used in the catalyst (9) of the present invention is a
catalyst obtained by supporting ruthenium on a chromium oxide
carrier.
[0250] Ruthenium to be supported include ruthenium oxide, ruthenium
chloride and metal ruthenium. A catalyst obtained by calcining the
solid, which is obtained by supporting ruthenium chloride or metal
ruthenium on a carrier, can also be used. Preferable catalyst
includes ruthenium oxide catalyst supported on chromium oxide,
ruthenium chloride catalyst supported on chromium oxide, a catalyst
obtained by calcining ruthenium chloride catalyst supported on
chromium oxide, metal ruthenium catalyst supported on chromium
oxide, and catalyst obtained by calcining metal ruthenium oxide
catalyst supported on chromium oxide. More preferable catalyst
includes ruthenium oxide catalyst supported on chromium oxide, and
a catalyst obtained by calcining ruthenium chloride catalyst
supported on chromium oxide. More preferable catalyst includes
ruthenium oxide catalyst supported on chromium oxide obtained by
calcining ruthenium hydroxide catalyst supported on chromium oxide,
and a catalyst obtained by calcining ruthenium chloride catalyst
supported on chromium oxide.
[0251] The process of supporting ruthenium includes impregnation
process, ion exchange process and precipitation supporting process.
Among them, impregnation process and precipitation supporting
process are preferred. A weight ratio of ruthenium to the carrier
is preferably within a range from 0.1/99.9 to 20/80, and preferably
from 0.5/99.5 to 10/90. When the amount of ruthenium is too small,
the activity is lowered sometimes. On the other hand, when the
amount of ruthenium is too large, the price of the catalyst becomes
high sometimes.
[0252] The process of calcining the catalyst obtained by supporting
ruthenium on the carrier includes process of heating to
200-500.degree. C. in a gas containing oxygen. The gas containing
oxygen includes air and air diluted with nitrogen. Preferable
calcination temperature is from 280 to 500C, and more preferably
from 300 to 450.degree. C. The calcination time is usually from 30
minutes to 10 hours.
[0253] The third component other than the ruthenium compound may
also be added, and the third component includes, for example,
palladium compound, copper compound, chromium compound, vanadium
compound, nickel compound, alkali metal compound, rare earth
compound, manganese compound and alkali earth compound. The amount
of the third component to be added is preferably form 0.1 to 10% by
weight in terms of a proportion to the carrier.
[0254] The chromium oxide carrier means chromium oxide alone, or a
mixture of chromium oxide and an oxide of element, or chromium
mixed oxide. The oxide of the element to be mixed with chromium
oxide includes alumina, silica, silica-alumina, zeolite,
diatomaceous earth, titanium oxide and zirconium oxide. The
chromium mixed oxide includes chromia-silica, chromia-alumina,
chromia-titania and chromia-zirconia. A weight ratio of the
additives to chromium oxide is usually within a range from 0/100 to
50/50, and preferably from 0/100 to 30/70. The proportion of
chromium contained in the chromium mixed oxide is usually not less
than 10% by weight, and preferably not less than 50% by weight.
[0255] Preferable chromium oxide carrier includes chromium oxide
and chromia-titania. More preferable chromium oxide carrier is
chromium oxide alone.
[0256] The chromium oxide carrier can be used in the form of a
powder, or can also used after molding. The chromium carrier may be
a commercially available one, and may also be prepared by using a
chromium compound.
[0257] The process for preparing the catalyst includes various
processes. For example, the process for preparing the catalyst
obtained by calcining the ruthenium chloride supported on chromium
oxide includes the following preparation process. That is, there
can be used a process of dissolving ruthenium chloride such as
commercially available ruthenium chloride hydrate
(RuCl.sub.3.nH.sub.2O) in a solvent, impregnating a chromium oxide
carrier with the resulting solution, and drying and calcining.
[0258] The solvent in which ruthenium chloride is dissolved
includes water, hydrochloric acid, and an organic solvent such as
methanol, and water or hydrochloric acid is preferred. The amount
of ruthenium chloride to be impregnated is usually from 0.1 to 20%
by weight, and preferably from 0.5 to 10% by weight, in terms of
ruthenium. The drying temperature is usually from 50 to 100.degree.
C. The calcination temperature is usually from 200 to 600.degree.
C., preferably from 280 to 500.degree. C., and more preferably from
300 to 450.degree. C. The calcination atmosphere includes gas
containing oxygen and nitrogen, preferably gas containing oxygen.
Preferable examples of the gas containing oxygen include air. The
calcination time is usually from 30 minutes to 10 hours.
[0259] The process for preparing the ruthenium oxide catalyst
supported on chromium oxide includes the following preparation
process, that is, a process of suspending a chromium oxide carrier
in a solution obtained by dissolving ruthenium chloride such as
commercially available ruthenium chloride hydrate
(RuCl.sub.3.nH.sub.2O) in a solvent, adding an alkali, hydrolyzing
ruthenium chloride to form ruthenium hydroxide resulting in
supporting it on the carrier by precipitation, and oxidizing the
supported one to obtain a ruthenium oxide catalyst supported on
chromium oxide. The solvent in which ruthenium chloride is
dissolved includes water, aqueous hydrochloric acid solution, and
an organic solvent such as methanol, and water or an aqueous
hydrochloric acid solution is preferred.
[0260] The alkali includes aqueous solution of hydroxide of alkali
metal, ammonia, carbonate of alkali metal, and carbonate of
ammonia, and an aqueous solution of hydroxide of an alkali metal is
preferred.
[0261] Preferable process of oxidizing supported ruthenium
hydroxide includes a process of calcining in an air.
[0262] The calcination temperature is preferably from 280 to
500.degree. C., and more preferably from 300 to 450.degree. C. The
calcination can also be conducted in two stages. When the
calcination is conducted in two stages, the first stage is
preferably conducted at low temperature ranging from 150 to
300.degree. C. The calcination time is usually from 30 minutes to
10 hours.
[0263] The amount of ruthenium oxide to be supported is usually
from 0.1 to 20% by weight, and preferably from 0.5 to 10% by
weight, in terms of ruthenium.
[0264] The process for preparing a ruthenium oxide catalyst
supported on chromium oxide also includes the following preparation
process.
[0265] That is, preferable examples thereof include a process of
impregnating a chromium oxide carrier with an aqueous ruthenium
chloride solution, adding an alkali, hydrolyzing ruthenium chloride
to deposit ruthenium hydroxide on the carrier, and calcining it
under air. The alkali includes aqueous solution of hydroxide of
alkali metal, ammonia, carbonate of alkali metal, and carbonate of
ammonia, and an aqueous solution of hydroxide of an alkali metal is
preferred. Preferable examples of the calcination conditions
include the above conditions.
[0266] As described above, preferable examples of the ruthenium
oxide catalyst supported on chromium oxide include catalyst
obtained by supporting ruthenium hydroxide on a carrier and
calcining the supported one under air.
[0267] It can be confirmed by X-ray analysis and analysis by XPS
(X-ray photoelectron spectroscopy) that the ruthenium compound was
converted into ruthenium oxide.
[0268] The process for preparing metal ruthenium catalyst supported
on chromium oxide includes a process of impregnating a chromium
oxide carrier with an aqueous ruthenium chloride solution, and
reducing by using a reducing agent such as hydrogen, and preferable
examples thereof include a process of impregnating a chromium oxide
carrier with a solution obtained by dissolving commercially
available ruthenium chloride hydrate (RuCl.sub.3.nH.sub.2O) in a
solvent, drying the impregnated one, and reducing by calcining in a
gas containing hydrogen or reducing by using a reducing agent such
as sodium boron hydride or hydrazine.
[0269] The process for preparing a catalyst obtained by calcining a
metal ruthenium catalyst supported on chromium oxide includes the
following preparation process. That is, preferable examples thereof
include a process of calcining the above-mentioned metal ruthenium
catalyst supported on chromium oxide in a gas containing oxygen.
The calcination temperature is preferably from 280 to 500.degree.
C., and more preferably from 300 to 450.degree. C. The calcination
time is usually from 30 minutes to 10 hours.
[0270] It is an object of the present invention to obtain chlorine
by oxidizing hydrogen chloride with oxygen using the above
catalyst. The reaction system used to obtain chlorine includes, for
example, a flow system such as fixed bed or fluidized bed, and a
gas phase reaction such as fixed bed flow system and gas phase
fluidized bed flow system can be preferably used. The fixed bed
system has an advantage that separation between the reaction gas
and catalyst is not required and that high conversion can be
accomplished because a raw gas can be sufficiently contacted with a
catalyst. The fluidized bed system has an advantage that heat in
the reactor can be sufficiently removed and temperature
distribution width in the reactor can be minimized
[0271] When the reaction temperature is high, volatilization of
ruthenium oxide in a highly oxidized state occurs. Therefore, the
reaction is preferably conducted at low temperature and the
reaction temperature is usually from 100 to 500.degree. C.,
preferably from 200 to 400.degree. C., more preferably from 200 to
380.degree. C. The reaction pressure is usually from about
atmospheric pressure to 50 atm. As the raw material of oxygen, an
air may be used as it is, or pure oxygen may also be used. Since
other components are also discharged simultaneously when an inert
nitrogen gas is discharged out of the plant , pure oxygen
containing no inert gas is preferable. The theoretic molar amount
of oxygen based on hydrogen chloride is 1/4 mol, but oxygen is
usually fed in an amount that is 0.1-10 times of the theoretical
amount. In the case of the fixed bed gas phase flow system, the
amount of the catalyst to be used is usually from about 10 to 20000
h.sup.-1 in terms of a ratio (GHSV) to a feed rate of hydrogen
chloride as the raw material under atmospheric pressure. GHSV means
gas hourly space velocity which is a ratio of a volume of feed
hydrogen chloride gas (1/h) to volume of catalyst (1).
[0272] The present invention which relates to a process for
producing a supported ruthenium oxide catalyst will be described
below.
[0273] The supported ruthenium oxide catalyst produced in the
catalyst (1) of the present invention is a supported ruthenium
oxide catalyst prepared in a ruthenium compound supporting step, an
alkali treating step, a reducing compound treating step and an
oxidizing step, more preferably a supported ruthenium oxide
catalyst prepared in a ruthenium halide supporting step, an alkali
treating step, a reducing compound treating step and an oxidizing
step, and still more preferably a supported ruthenium oxide
catalyst prepared in a ruthenium halide supporting step, an alkali
treating step, a reducing compound treatment step, an alkali metal
chloride adding step and an oxidizing step.
[0274] The supported ruthenium oxide catalyst produced in the
catalyst (2) of the present invention is a supported ruthenium
oxide catalyst obtained by the steps which comprises supporting a
ruthenium compound on a carrier, treating the supported one by
using a reducing agent to form ruthenium having an oxidation number
of 1 to less than 4 valence, and oxidizing the resulted one.
[0275] The process for preparing the supported ruthenium oxide
catalyst includes various processes. For example, a process for
preparing a catalyst comprising ruthenium oxide having an oxidation
number of 4 valence supported on a carrier can be prepared by
supporting ruthenium chloride on a carrier, hydrolyzing the
supported one by using an alkali, and calcining under air.
Alternatively, a process for preparing a catalyst comprising
supported ruthenium oxide having an oxidation number of 4 valence
can also be prepared by supporting ruthenium chloride on a carrier,
reducing the supported one by using various reducing agents to form
ruthenium having a valence of 0, and calcining under air. It is
also possible to exemplify a preparation example of a supported
ruthenium oxide catalyst comprising supported ruthenium oxide
having an oxidation number of 4, which is prepared by supporting
ruthenium chloride on a carrier, treating the supported one by
using a mixed solution of various reducing compounds and basic
compounds, or treating by using an aqueous alkali solution of a
reducing compound, or treating by using various reducing agents,
thereby to form a ruthenium compound having an oxidation number of
1 to less than 4 valence, and calcining under air. The catalyst
prepared by this preparation process can be exemplified as a
preparation example which is most active to the oxidizing reaction
of hydrogen chloride. The process of adjusting the oxidation number
of the ruthenium compound supported on the carrier within a range
from 1 to less than 4 valence includes various processes, for
example, process of treating by using a mixed solution of a
reducing compound and a basic compound, process of treating by
using an alkali solution of a reducing compound, process of
treating by using an organolithium compound, an organosodium
compound or an organopotassium compound, process of treating by
using an organoaluminum compound, process of treating by using an
organomagnesium compound, and process of treating by using
hydrogen. When using these reducing agents in an excess amount, the
ruthenium compound is reduced to the valence of 0 and, therefore,
it is necessary to use it in a suitable amount.
[0276] The process of measuring the oxidation number of the
supported ruthenium includes various processes. For example, since
nitrogen is mainly generated when using hydrazine as the reducing
agent, the valence number of ruthenium can be determined by the
amount of nitrogen generated.
[0277] The reaction scheme will be shown below. 2
[0278] For example, when the ruthenium compound is reduced by using
hydrazine under the conditions of an aqueous alkali solution, a
hydroxide of ruthenium is formed. Therefore, the oxidation number
of ruthenium can also be determined by measuring a ratio of
ruthenium to oxygen and chlorine bound to ruthenium due to
elemental analysis after dehydration under vacuum.
[0279] In the present invention, the oxidation number of ruthenium
was determined from the amount of nitrogen generated by using the
scheme (1).
[0280] The common part with the processes (1) and (2) for producing
the catalyst will be explained.
[0281] The carrier includes, for example, oxides and mixed oxides
of elements, such as titanium oxide, alumina, zirconium oxide,
silica, titanium mixed oxide, zirconium mixed oxide, aluminum mixed
oxide, silicon mixed oxide and the like. Preferable carriers are
titanium oxide, alumina, zirconium oxide and silica, and more
preferable carrier is titanium oxide.
[0282] The ruthenium compound to be supported on the carrier
include compounds, for example, ruthenium chloride such as
RuCl.sub.3 and RuCl.sub.3 hydrate; chlororuthenate such as
K.sub.3RuCl.sub.6, [RuCl.sub.6].sup.3- and K.sub.2RuCl.sub.6;
chlororuthenate hydrate such as [RuCl.sub.5(H.sub.2O).sub.4].sup.2-
and [RuCl.sub.2(H.sub.2O).sub.4].s- up.+; salt of ruthenic acid,
such as K.sub.2RuO.sub.4; rutheniumoxy chloride such as
Ru.sub.2OCl.sub.4, Ru.sub.2OCl.sub.5 and Ru.sub.2OCl.sub.6; salt of
rutheniumoxy chloride, such as K.sub.2Ru.sub.2OCl.sub.10 and
Cs.sub.2Ru.sub.2OCl.sub.4; ruthenium-ammine complex such as
[(Ru(NH.sub.3).sub.6].sup.2+, [Ru(NH.sub.3).sub.6].sup.3+ and
[Ru(NH.sub.3).sub.5H.sub.2O].sup.2+; chloride and bromide of
ruthenium-ammine complex, such as [Ru(NH.sub.3).sub.5Cl].sup.2+,
[Ru(NH.sub.3).sub.6] Cl.sub.2, [Ru(NH.sub.3).sub.6]Cl.sub.3 and
[Ru(NH.sub.3).sub.6]Br.sub.3; ruthenium bromide such as RuBr.sub.3
and RuBr.sub.3 hydrate; other ruthenium-organoamine complex;
ruthenium-acetylacetonato complex; ruthenium-carbonyl complex such
as Ru(CO).sub.5 and Ru.sub.3(CO).sub.12; ruthenium organic acid
salt such as
[Ru.sub.3O(OCOCH.sub.3).sub.6(H.sub.2O).sub.3]OCOCH.sub.3 hydrate
and Ru.sub.2(RCOO).sub.4Cl(R: alkyl group having carbon atoms of
1-3); ruthenium-nitrosyl complex such as K.sub.2[RuCl.sub.5(NO)]],
[Ru(NH.sub.3).sub.5(NO)]Cl.sub.3, [(Ru(OH)
(NH.sub.3).sub.4(NO)](NO.sub.3- ).sub.2 and Ru(NO)
(NO.sub.3).sub.3; and ruthenium-phosphine complex. Preferable
ruthenium compounds are ruthenium halide compounds, for example,
ruthenium chloride such as RuCl.sub.3 and RuCl.sub.3 hydrate and
ruthenium bromide such as RuBr.sub.3 and RuBr.sub.3 hydrate.
Preferable ruthenium halide includes ruthenium chloride such as
RuCl.sub.3 and RuCl.sub.3 hydrate and ruthenium bromide such as
RuBr.sub.3 and RuBr.sub.3 hydrate. More preferred one is a
ruthenium chloride hydrate.
[0283] The process of supporting the ruthenium compound on the
carrier includes, for example, impregnation process and equilibrium
adsorption process.
[0284] The alkali used in the alkali treating step includes, for
example, hydroxide, carbonate and hydrogencarbonate of alkali
metal; aqueous solution or solution of an organic solvent such as
alcohol of ammonia, ammonium carbonate and ammonium
hydrogencarbonate. As the alkali, for example, hydroxide, carbonate
and hydrogencarbonate of alkali metal are preferably used. As the
solvent, water is preferably used. It is also a preferable process
to use one obtained by dissolving a reducing compound in an alkali
solution.
[0285] The reducing compound used in the reducing compound treating
step includes, for example, hydrazine, methanol, ethanol,
formaldehyde, hydroxylamine or formic acid, or an aqueous solution
of hydrazine, methanol, ethanol, formaldehyde, hydroxylamine or
formic acid, or a solution of an organic solvent such as alcohol.
Preferred are hydrazine, methanol, ethanol, formaldehyde, and
solutions of hydrazine, methanol, ethanol and formaldehyde. More
preferred are hydrazine and a solution of hydrazine. The reducing
compound used for treating the ruthenium compound supported on the
carrier includes, for example, a compound having a redox potential
of -0.8 to 0.5 V, a solution thereof, and a solution of an organic
solvent such as alcohol. Now a standard electrode potential is used
in place of the redox potential. Among the compounds listed above,
a standard electrode potential of hydrazine is -0.23 V, that of
formaldehyde is 0.056 V and that of formic acid is -0.199 V,
respectively. It is also a preferable process to use an aqueous
alkali solution of the reducing compound.
[0286] The basic compound for preparing the catalyst (2) includes,
for example, ammonia; amine such as alkyl amine, pyridine, aniline,
trimethylamine and hydroxyl amine; alkali metal hydroxide such as
potassium hydroxide, sodium hydroxide and lithium hydroxide; alkali
metal carbonate such as potassium carbonate, sodium carbonate and
lithium carbonate; hydroxide of quaternary ammonium salt; and alkyl
aluminum such as triethyl aluminum.
[0287] The process of treating by using a reducing compound
includes, for example, a process of dipping one obtained in the
alkali treating step in a reducing compound or a solution of a
reducing compound, or impregnating with a reducing compound or a
solution of a reducing compound. It is also a preferable process to
use an aqueous alkali solution of the reducing compound.
[0288] A process of treating by using a reducing compound or an
aqueous alkali solution of a reducing compound, and adding an
alkali metal chloride is also a preferable process.
[0289] The process of oxidizing includes, for example, process of
calcining under air.
[0290] A weight ratio of ruthenium oxide to the carrier is
preferably within a range from 0.1/99.9 to 20.0/80.0, more
preferably from 0.5/99.5 to 15.0/85.0, and still more preferably
from 1.0/99.0 to 15.0/85.0. When the ratio of ruthenium oxide is
too low, the activity is lowered sometimes. On the other hand, when
the ratio of ruthenium oxide is too high, the price of the catalyst
becomes high sometimes. Examples of the ruthenium oxide to be
supported include ruthenium dioxide, ruthenium hydroxide and the
like.
[0291] The embodiment of the process for preparing the supported
ruthenium oxide catalyst produced by the processes (1) and (2) for
producing the catalyst of the present invention include a
preparation process comprising the following steps:
[0292] a ruthenium compound supporting step: step of supporting a
ruthenium compound on a carrier of a catalyst;
[0293] an alkali treating step: step of adding an alkali to one
obtained in the ruthenium compound supporting step;
[0294] a reducing compound treating step: step of treating one
obtained in the alkali treating step by using a reducing compound;
and
[0295] an oxidizing step: step of oxidizing one obtained in the
reducing compound treating step.
[0296] It is also preferred to use an aqueous alkali solution of a
reducing compound to simultaneously conduct the alkali treating
step and the reducing compound treating step in the above step.
[0297] Preferred embodiment of the process of preparing the
supported ruthenium oxide catalyst produced by the processes (1)
and (2) for producing the catalyst of the present invention include
a preparation process comprising the following steps:
[0298] a ruthenium halide compound supporting step: step of
supporting a ruthenium halide compound on a carrier of a
catalyst;
[0299] an alkali treating step: step of adding an alkali to one
obtained in the ruthenium halide compound supporting step;
[0300] a reducing compound treating step: step of treating one
obtained in the alkali treating step by using hydrazine, methanol,
ethanol or formaldehyde; and
[0301] an oxidizing step: step of oxidizing one obtained in the
reducing compound treating step.
[0302] It is also preferred to use an aqueous alkali solution of a
reducing compound to simultaneously conduct the alkali treating
step and the reducing compound treating step in the above step.
[0303] More preferred embodiment of the process of preparing the
supported ruthenium oxide catalyst produced by the processes (1)
and (2) for producing the catalyst of the present invention include
a preparation process comprising the following steps:
[0304] a ruthenium halide supporting step: step of supporting
ruthenium halide on a carrier of a catalyst;
[0305] an alkali treating step: step of adding an alkali to one
obtained in the ruthenium halide supporting step;
[0306] a hydrazine treating step: step of treating one obtained in
the alkali treating step by using hydrazine; and
[0307] an oxidizing step: step of oxidizing one obtained in the
hydrazine treating step.
[0308] It is also preferred to use an aqueous alkali solution of
hydrazine to simultaneously conduct the alkali treating step and
the hydrazine treating step in the above step.
[0309] Still more preferred embodiment of the process of preparing
the supported ruthenium oxide catalyst produced by the processes
(1) and (2) for producing the catalyst of the present invention
include a preparation process comprising the following steps:
[0310] a ruthenium halide supporting step: step of supporting
ruthenium halide on a carrier of a catalyst;
[0311] an alkali treating step: step of adding an alkali to one
obtained in the ruthenium halide supporting step;
[0312] a hydrazine treating step: step of treating one obtained in
the alkali treating step by using hydrazine;
[0313] an alkali metal chloride-adding step: step of adding an
alkali metal chloride to one obtained in the hydrazine treating
step; and
[0314] an oxidizing step: step of oxidizing one obtained in the
alkali metal chloride adding step.
[0315] It is also preferred to use an aqueous alkali solution of
hydrazine to simultaneously conduct the alkali treating step and
the hydrazine treating step in the above step.
[0316] The ruthenium halide supporting step is a step of supporting
ruthenium halide on a carrier of a catalyst. The ruthenium compound
to be supported on the carrier includes, for example, already
listed various ruthenium compounds. Among them, preferred examples
thereof are halides of ruthenium, for example, ruthenium chloride
such as RuCl.sub.3 and RuCl.sub.3 hydrate and ruthenium bromide
such as RuBr.sub.3 and RuBr.sub.3 hydrate. Preferred examples of
the ruthenium halide include ruthenium chloride such as RuCl.sub.3
and RuCl.sub.3 hydrate and ruthenium bromide such as RuBr.sub.3 and
RuBr.sub.3 hydrate. More preferred one is a ruthenium chloride
hydrate.
[0317] The amount of ruthenium halide used in the ruthenium halide
supporting step is usually an amount corresponding to a preferable
weight ratio of ruthenium oxide to the carrier. That is, is
supported by using a process of impregnating a solution of
ruthenium halide with already listed carrier or adsorbing said
solution to already listed carrier. As the solvent, for example,
water and an organic solvent such as alcohol are used, and water is
preferred. The impregnated one can be dried, and can also be
treated by using an alkali without being dried, but it is
preferable the impregnating one is dried. Regarding the conditions
for drying the impregnated one, the drying temperature is
preferably from 50 to 200.degree. C. and the drying time is
preferably from 1 to 10 hours.
[0318] The alkali treating step is a step for adding an alkali to
one obtained in the ruthenium halide supporting step. The alkali
used in the alkali treating step includes, for example, hydroxide,
carbonate and hydrogencarbonate of alkali metal; aqueous solution
of ammonia, ammonium carbonate and ammonium hydrogencarbonate; and
solution of an organic solvent such as alcohol. As the alkali, for
example, hydroxide, carbonate and hydrogencarbonate of alkali metal
are preferably used. As the solvent, for example, water is
preferably used. The concentration of the alkali varies depending
on the kind of alkali to be used, but is preferably from 0.1 to 10
mol/l.
[0319] Regarding a molar ratio of the ruthenium halide to the
alkali is, for example, 3 mol of sodium hydrooxide is equivalent to
1 mol of ruthenium halide in case of using sodium hydroxide.
Preferably, the alkali is used in the amount of 0.1-20 times
equivalent per that of ruthenium halide. The process of adding the
alkali include a process of impregnating with a solution of the
alkali or a process of dipping in a solution of the alkali. The
time of impregnation with the solution of the alkali is usually
within 60 minutes. Since the activity of the catalyst decreases
when the impregnation time is long, the impregnation time is
preferably within 10 minutes. The impregnation temperature is
preferably from 0 to 100.degree. C., and more preferably from 10 to
60.degree. C.
[0320] The hydrazine treating step is a step of treating one
obtained in the alkali treating step by using hydrazine. The
process of treating by using hydrazine includes, for example, a
process of impregnating with a solution of hydrazine and a process
of dipping in a solution of hydrazine. The supported ruthenium
halide treated by using the alkali in the previous step and an
alkali solution may be added to a hydazine solution in a state of
being mixed, or may be added to the hydazine solution after the
alkaline solution was separated by filtration. A preferable process
is a process of impregnating the supported ruthenium halide with
the alkali and immediately adding to the hydrazine solution. The
concentration of hydrazine used in the hydrazine treating step is
preferably not less than 0.1 mol/l.Hydrazine hydrate such as
hydrazine monohydrate may be used as it is. Alternatively, it is
used as a solution of an organic solvent such as alcohol.
Preferably, an aqueous solution of hydrazine or hydrazine hydrate
is used. Anhydride and a monohydrate of hydrazine can also be used.
Regarding a molar ratio of ruthenium halide to hydrazine, hydrazine
is used in the amount of 0.1 to 20 mol per mol of ruthenium halide.
The time of impregnation with the solution of hydrazine is
preferably from 5 minutes to 5 hours, and more preferably from 10
minutes to 2 hours. The temperature is preferably from 0 to
100.degree. C., and more preferably from 10 to 60.degree. C. After
dipping in the hydrazine solution, the dipping one is preferably
separated from the solution by filtration.
[0321] It is also preferred to use an aqueous alkali solution of
hydrazine to simultaneously conduct the alkali treating step and
hydrazine treating step in the above step. Preferable process
includes a process of slowly dipping one obtained in the ruthenium
halide supporting step to those prepared by mixing a preferable
amount of the alkali with a preferable amount of hydazine, and
treating for 5 minutes to 5 hours.
[0322] More preferable process includes a process of washing a
solid produced in the alkali treating step and hydrazine treating
step, thereby to remove the alkali and hydrazine, and then drying,
adding an alkali metal chloride in the following alkali metal
chloride adding step, drying, and oxidizing.
[0323] More preferable process includes a process of washing a
solid produced in the alkali treating step and hydrazine treating
step by using an aqueous solution of an alkali metal chloride, and
then drying, and oxidizing. This process is preferred because the
removal of the alkali and hydrazine, and the addition of the alkali
metal chloride can be conducted in the same step.
[0324] The alkali metal chloride adding step is a step of adding an
alkali metal chloride to one obtained in the alkali treating step
and hydrazine treating step. This step is not an indispensable step
to prepare the supported ruthenium oxide catalyst, but the activity
of the catalyst is further improved by conducting said step. That
is, the resulting solid is oxidized by the following oxidizing
step, but it is a preferable preparation example to convert it into
highly active supported ruthenium oxide by oxidizing the resulting
solid treated with the alkali and hydrazine in the presence of an
alkali metal salt.
[0325] The alkali metal chloride includes, for example, chloride of
alkali metal, such as potassium chloride and sodium chloride.
Preferable alkaline metal chlorides are potassium chloride and
sodium chloride, and more preferable one is potassium chloride. A
molar ratio of the alkali metal salt to ruthenium is preferably
from 0.01 to 10, and more preferably from 0.1 to 5.0. When the
amount of the alkali metal salt used is too small, sufficient
highly active catalyst is not obtained. On the other hand, when the
amount of the alkali metal salt used is too large, the cost becomes
high from an industrial point of view.
[0326] The process of impregnating with the aqueous alkali metal
chloride solution includes a process of impregnating the resulting
supported ruthenium one obtained by washing, drying, treating by
using hydrazine, but more preferable process includes a process of
impregnating the resulting supported ruthenium one treated with the
alkali and hydrazine by washing with an aqueous alkali metal
chloride solution without being washed with water.
[0327] For the purpose of adjusting the pH in the case of washing
the resulting supported ruthenium one, hydrochloric acid can also
be added to an aqueous solution of the alkali metal chloride. The
concentration of the aqueous solution of the alkali metal chloride
is preferably from 0.01 to 10 mol/l, and more preferably from 0.1
to 5 mol/l.
[0328] The purpose of washing lies in removal of the alkali and
hydrazine, but the alkali and hydrazine can also be remained as far
as the effect of the present invention is not adversely
affected.
[0329] After impregnating with the alkali metal chloride, the
catalyst is usually dried. Regarding the drying conditions, the
drying temperature is preferably from 50 to 200.degree. C. and the
drying time is preferably from 1 to 10 hours.
[0330] The oxidizing step is a step of oxidizing one obtained in
the alkali treating step and hydrazine treating step (in the case
of using no alkali metal chloride adding step), or a step of
oxidizing one obtained in the alkali metal chloride adding step (in
the case of using the alkali metal chloride adding step). The
oxidizing step can include a process of calcining under air. It is
a preferable preparation example to convert it into highly active
supported ruthenium oxide by calcining one treated with the alkali
and hydrazine in the presence of an alkali metal salt in a gas
containing oxygen. A gas containing oxygen usually includes
air.
[0331] The calcination temperature is preferably from 100 to
600.degree. C., and more preferably from 280 to 450.degree. C. When
the calcination temperature is too low, particles formed by the
alkali treatment and hydrazine treatment are remained in a large
amount in the form of a ruthenium oxide precursor and, therefore,
the activity of the catalyst becomes insufficient sometimes. On the
other hand, when the calcination temperature is too high,
agglomeration of ruthenium oxide particles occur and, therefore,
the activity of the catalyst is lowered. The calcination time is
preferably from 30 minutes to 10 hours.
[0332] In this case, it is important to calcine in the presence of
the alkali metal salt. By using this process, it is possible to
obtain higher activity of the catalyst because that process of
forming more fine particle of ruthenium oxide, comparing the
process which includes calciing in the substantially absence of the
alkali metal salt.
[0333] By the calcination, the particles supported on the carrier,
which are formed by the alkali treatment and hydrazine treatment,
are converted into a supported ruthenium oxide catalyst. It can be
confirmed by analysis such as X-ray diffraction and XPS (X-ray
photoelectron spectroscopy) that the particles formed by the alkali
treatment and hydrazine treatment were converted into ruthenium
oxide. Incidentally, substantially total amount of particles formed
by the alkali treatment and hydrazine treatment are preferably
converted into ruthenium oxide, but the particles formed by the
alkali treatment and hydrazine treatment can be remained as far as
the effect of the present invention is not adversely affected.
[0334] The process of oxidizing one treated with the alkali and
hydrazine, washing the remained alkali metal chloride, and drying
the washed one is a preferable preparation process. It is preferred
that the alkali metal chloride contained on calcination is
sufficiently washed with water. The process of measuring the alkali
metal chloride after washing includes a process of examining the
presence/absence of white turbidity by adding an aqueous silver
nitrate solution to the filtrate. However, the alkali metal
chloride may be remained as far as the effect of the present
invention is not adversely affected.
[0335] According to a preferable preparation process, the washed
catalyst is then dried. Regarding the drying conditions, the drying
temperature is preferably from 50 to 200.degree. C. and the drying
time is preferably from 1 to 10 hours.
[0336] The supported ruthenium oxide catalyst produced by the above
steps is highly active, and the activity was higher than that of
the catalyst prepared by oxidizing a catalyst obtained by reducing
ruthenium chloride with hydrogen. Furthermore, a catalyst obtained
by previously treating ruthenium chloride by using an alkali,
treating by using hydrazine, or treating by using alkali and
hydrazine simultaneously, and oxidizing showed higher activity than
that of a catalyst obtained by treating ruthenium chloride with
hydrazine, and oxidizing.
[0337] The supported ruthenium oxide catalyst produced by the
process (3) for producing the catalyst of the present invention is
a supported ruthenium oxide catalyst using titanium oxide
containing rutile titanium oxide as a carrier. As the titanium
oxide, for example, rutile titanium oxide, anatase titanium oxide
and non-crystal titanium oxide are known. The titanium oxide
containing rutile titanium oxide used in the present invention
refers to one containing a rutile crystal by measuring a ratio of
the rutile crystal to the anatase crystal in the titanium oxide by
X-ray diffraction analysis. The measuring process will be described
in detail hereinafter. When the chemical composition of the carrier
used in the present invention is composed of titanium oxide alone,
the proportion of the rutile crystal is determined from a ratio of
the rutile crystal to the anatase crystal in the titanium oxide by
using X-ray diffraction analysis. In the present invention, a mixed
oxide of the titanium oxide and other metal oxide is also used. In
that case, the proportion of the rutile crystal is determined by
the following process. The oxide to be mixed with the titanium
oxide includes oxides of elements, and preferred examples thereof
include alumina, zirconium oxide and silica. The proportion of the
rutile crystal in the mixed oxide is also determined from the ratio
of the rutile crystal to the anatase crystal in the titanium oxide
by using X-ray diffraction analysis, but it is necessary to contain
the rutile crystal. In this case, the content of the oxide other
than the titanium oxide in the mixed oxide is within a range from 0
to 60% by weight. Preferred carrier includes titanium oxide which
does not contain a metal oxide other than titanium oxide.
[0338] It is necessary that the titanium oxide contains the rutile
crystal. The content of the rutile crystal is preferably not less
than 10%, more preferably not less than 30%, and most preferably
not less than 80%.
[0339] The process for preparing the titanium oxide containing the
rutile crystal includes various processes. In general, the
following processes are exemplified. For example, when using
titanium tetrachloride as a raw material, titanium tetrachloride is
dissolved by adding dropwise in ice-cooled water, and then
neutralized with an aqueous ammonia solution to form titanium
hydroxide (ortho-titanic acid). Thereafter, the formed precipitate
was washed with water to remove a chlorine ion. In that case, when
the temperature on neutralization becomes higher than 20.degree. C.
or the chlorine ion is remained in the titanium oxide after
washing, conversion into a stable rutile crystal is liable to occur
on calcination. When the calcination temperature becomes not less
than 600.degree. C., conversion into rutile occurs (Catalyst
Preparation Chemistry, 1989, page 211, Kodansha). For example, a
reaction gas is prepared by passing an oxygen-nitrogen mixed gas
through a titanium tetrachloride evaporator and the reaction gas is
introduced into a reactor. The reaction between titanium
tetrachloride and oxygen starts at a temperature of about
400.degree. C. and titanium dioxide formed by the reaction of a
TiCl.sub.4-O.sub.2 system is mainly an anatase type. However, when
the reaction temperature becomes not less than 900.degree. C.,
formation of a rutile type can be observed (Catalyst Preparation
Chemistry, 1989, page 89, Kodansha). The preparation process
includes, for example, a process of hydrolyzing titanium
tetrachloride in the presence of ammonium sulfate and calcining
(e.g. Shokubai Kougaku Kouza 10, Catalyst Handbook by Element,
1978, page 254, Chijin Shokan) and a process of calcining an
anatase titanium oxide (e.g. Metal Oxide and Mixed Oxide, 1980,
page 107, Kodansha). Furthermore, rutile titanium oxide can be
obtained by a process for hydrolyzing an aqueous solution of
titanium tetrachloride by heating. Rutile titanium oxide is also
formed by previously mixing an aqueous titanium compound solution
of titanium sulfate or titanium chloride with a rutile titanium
oxide powder, hydrolyzing the mixture by heating or using an
alkali, and calcining at low temperature of about 500.degree.
C.
[0340] The process of determining the proportion of the rutile
crystal in the titanium oxide includes a X-ray diffraction analysis
and, as a X-ray source, various X-ray sources can be used. For
example, a K .alpha. ray of copper is used. When using the K
.alpha. ray of copper, the proportion of the rutile crystal and the
proportion of the anatase are respectively determined by using an
intensity of a diffraction peak of 2.theta.=27.5 degree of the
plane (110) and an intensity of a diffraction peak of 2.theta.=25.3
degree of the plane (101). The carrier used in the present
invention is one having a peak intensity of the rutile crystal and
a peak intensity of the anatase crystal, or one having a peak
intensity of the rutile crystal. That is, the carrier has both of a
diffraction peak intensity of the rutile crystal and a diffraction
peak of the anatase crystal, or has only a diffraction peak of the
rutile crystal. Preferred carrier is one wherein a proportion of
the peak intensity of the rutile crystal to the total of the peak
intensity of the rutile crystal and the peak intensity of the
anatase crystal is not less than 10%. Also in the supported
ruthenium oxide catalyst using the titanium oxide carrier
containing rutile titanium oxide, an amount of an OH group
contained in the carrier is preferably similar amount to the
catalyst which is produced by the process (4) of the present
invention. Although the details will be described with regard as
the process (4) for producing the catalyst of the present
invention, the amount of the OH group of the titanium oxide of the
carrier used in the catalyst is usually from 0.1.times.10.sup.-4 to
30.times.10.sup.-4 (mol/g-carrier), preferably from
0.2.times.10.sup.-4 to 20.times.10.sup.-4 (mol/g-carrier), and more
preferably from 3.0.times.10.sup.-4 to 15.times.10.sup.-4
(mol/g-carrier).
[0341] The supported ruthenium oxide catalyst produced by the
process (4) for producing the catalyst of the present invention is
a supported ruthenium oxide catalyst obtained by the steps which
comprises supporting a ruthenium compound on a carrier, treating
the supported one by using a reducing compound or a reducing agent
in a liquid phase, and oxidizing the resulted one, wherein titanium
oxide containing an OH group in an amount of 0.1.times.10.sup.-4 to
30.times.10.sup.-4 (mol/g-carrier) per unit weight of a carrier is
used as the carrier. The carrier includes, for example, rutile
crystal carrier, anatase crystal carrier and non-crystal carrier.
Preferable carriers are rutile crystal carrier and anatase crystal
carrier, and more preferable one is rutile crystal carrier. It is
generally known that a hydroxyl group represented by OH bound to Ti
exists on the surface of the titanium oxide. The titanium oxide
used in the present invention is one containing an OH group, and
the process of measuring the content of OH group will be described
in detail hereinafter. When the chemical composition of the carrier
used in the present invention is consisting essentially of titanium
oxide alone, it is determined from the content of the OH group in
the titanium oxide. In the present invention, a mixed oxide of the
titanium oxide and other metal oxide is also used. The oxide to be
mixed with the titanium oxide includes oxides of elements, and
preferred examples thereof include alumina, zirconium oxide and
silica. In that case, the content of the oxide other than the
titanium oxide in the mixed oxide is within a range from 0 to 60%
by weight. Also this case, the content of the OH group per unit
weight of the carrier contained in the carrier is determined by the
measuring process which is also described in detail hereinafter.
Preferred carrier is titanium oxide which does not contain the
metal oxide other than the titanium oxide.
[0342] When the content of the OH group of the carrier is large,
the carrier and supported ruthenium oxide may react each other,
resulting in deactivation. On the other hand, when the content of
the OH group of the carrier is small, the activity of the catalyst
is lowered sometimes by sintering of the supported ruthenium oxide
and the other phenomenon.
[0343] The process of determining the content of the OH group of
the titanium oxide includes various processes. For example, a
process using a thermogravimetric process (TG) is exemplified. When
using the thermogravimetric process, the temperature is kept
constant and, after removing excess water in a sample, the sample
is heated and the content of the OH group is measured from a weight
loss. According to this process, the amount of the sample is small
and it is difficult to measure with good accuracy. When heat
decomposable impurities exist in the carrier, there is a drawback
that the actual content of the OH group is not determined. When
using the measurement of ignition loss (Igloss) for measuring the
content of the OH group from the weight loss of the sample in the
same manner, the measurement with high accuracy can be conducted if
the amount of the sample is increased. However, an influence of the
heat decomposable impurities is exerted similar to the case of the
thermogravimetric process. Furthermore, there is also a drawback
that the weight loss obtained by the thermogravimetric process and
ignition loss measurement also includes the bulk OH group content
which is not effective on preparation of the catalyst.
[0344] A process using sodium naphthalene is also exemplified.
According to this process, an OH group in a sample is reacted with
sodium naphthalene as a reagent and then the content of the OH
group is measured from the titration amount of sodium naphthalene.
In this case, since a change in concentration of the reagent for
titration and a trace amount of water exert a large influence on
the results, the measuring results are influenced by the storage
state of the reagent. Therefore, it is very difficult to obtain a
value with good accuracy.
[0345] A titration process using an alkyl alkali metal is also
exemplified. The titration process using the alkyl alkali metal
includes a preferable process of suspending a titanium oxide
carrier or a titanium oxide carrier powder in a dehydrated solvent,
adding dropwise an alkyl alkali metal in a nitrogen atmosphere, and
determining the amount of the OH group contained in the titanium
oxide from the amount of hydrocarbon generated. In that case, since
an alkyl alkali metal and water contained in the dehydrated solvent
react each other to generate hydrocarbon, the content of the OH
group in the titanium oxide must be determined by subtracting the
generated amount from the measured value.
[0346] Most preferred process includes a process of suspending a
titanium oxide carrier or a titanium oxide carrier powder in a
dehydrated toluene , adding dropwise methyl lithium in a nitrogen
atmosphere, and determining the amount of the OH group contained in
the titanium oxide from the amount of methane generated, and the
content of the OH group in the titanium oxide catalyst of the
present invention is a value obtained by this process.
[0347] The measuring procedure includes, for example, the following
process. First, a sample is previously dried under air atmosphere
at a temperature of 150.degree. C. for 2 hours and then cooled in a
desiccator. Thereafter, a predetermined amount of the sample is
transferred in a flask whose atmosphere was replaced by nitrogen,
and then suspended in an organic solvent such as dehydrated
toluene. The flask is ice-cooled to inhibit heat generation and,
after adding dropwise methyl lithium from a dropping funnel, the
generated gas is collected and the volume at the measuring
temperature is measured. The content of the OH group thus
determined, which is used in the catalyst, is usually from
0.1.times.10.sup.-4 to 30.times.10.sup.-4 (mol/g-carrier),
preferably from 0.2.times.10.sup.-4 to 20.times.10.sup.-4
(mol/g-carrier), and more preferably from 3.0.times.10.sup.-4 to
15.times.10.sup.-4 (mol/g-carrier).
[0348] The process of adjusting the amount of the OH group
contained in the titanium oxide carrier to a predetermined amount
includes various processes. For example, a calcination temperature
and a calcination time of the carrier are used for adjusting the OH
group of the carrier. The OH group in the titanium oxide carrier is
eliminated by heating, and the content of the OH group can be
controlled by changing the calcination temperature and calcination
time. The calcination temperature of the carrier is usually from
100 to 1000.degree. C., and preferably from 150 to 800.degree. C.
The calcination time of the carrier is usually from 30 minutes to
12 hours. In this case, it is necessary to pay attention to the
point that the surface area of the carrier decreases with the
increase of the calcination temperature or the calcination time.
When the titanium oxide is produced from a gas phase, one having
small content of the OH group can be produced. Furthermore, when
the titanium oxide is produced from an aqueous phase such as
aqueous solution, one having large content of the OH group can be
produced. Furthermore, a process of treating the OH group of the
carrier by using an alkali and a process of reacting the OH group
by using 1,1,1-3,3,3-hexamethyldisilazane are exemplified
[0349] The present invention relates to a process for producing a
supported ruthenium oxide catalyst using the above carrier. A
weight ratio of ruthenium oxide to the carrier is usually within a
range from 0.1/99.9 to 20.0/80.0, preferably from 0.5/99.5 to
15.0/85.0, and more preferably from 1.0/99.0 to 15.0/85.0. When the
ratio of ruthenium oxide is too low, the activity is lowered
sometimes. On the other hand, when the ratio of ruthenium oxide is
too high, the price of the catalyst becomes high sometimes.
Examples of the ruthenium oxide to be supported include ruthenium
dioxide, ruthenium hydroxide and the like.
[0350] The process for preparing the supported ruthenium oxide
catalyst by using the above carrier is a process comprising the
steps of supporting a ruthenium compound on a carrier, treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase, and oxidizing. A process of treating the supported
one reducing by using a reducing compound or a reducing agent in a
liquid phase includes, for example, a process of treating the
supported one by using a reducing compound or a reducing agent in a
liquid phase which is conducted in the catalysts produced (1), (2)
of the present invention and in the catalysts reduced by a reducing
agent such as sodium boron hydride, and the process described
below. That is, the process includes a process of suspending one
comprising the already described ruthenium compound supported on
the carrier in an aqueous phase or an organic solvent, and bubbling
hydrogen, a process of treating by using an organolithium compound
such as butyl lithium, or an organosodium compound or an
organopotassium compound in an organic solvent, a process of
treating by using an organoaluminum compound such as trialkyl
aluminum, and a process of treating by using an organomagnesium
compound such as Grignard reagent. Furthermore, various
organometallic compounds can be used and examples thereof include
alkali metal alkoxide such as sodium methoxide; alkali metal
naphthalene compound such as sodium naphthalene; azide compound
such as sodium azide; alkali amide compound such as sodium amide;
organocalcium compound, organozinc compound; organoaluminum
alkoxide such as alkyl aluminum alkoxide; organotin compound;
organocopper compound; organoboron compound; boranes such as borane
and diborane; sodium ammonia solution; and carbon monoxide. Various
organic compound can also be used and examples thereof include
diazomethane, hydroquinone and oxalic acid.
[0351] In a process for producing a supported ruthenium oxide
catalyst, it is preferable that the catalyst (1) or (2) is a
supported ruthenium oxide catalyst obtained by using titanium oxide
containing not less than 10% by weight of rutile titanium oxide as
a carrier. It is more preferable that the catalyst (1) or (2) is a
supported ruthenium oxide catalyst obtained by using titanium oxide
containing not less than 30% by weight of rutile titanium oxide as
a carrier.
[0352] It is preferable that in the case of the catalyst (3) or
(4), said process comprises supporting a ruthenium compound on a
carrier, reducing the supported one by using a reducing
hydrogenated compound, and oxidizing.
[0353] It is preferable that in the case of the catalyst (3) or
(4), said process comprises supporting a ruthenium compound on a
carrier, treating the supported one by using a reducing compound,
and oxidizing.
[0354] It is preferable that in the case of the catalyst (3) or
(4), said process comprises supporting a ruthenium compound on a
carrier, treating the supported one by using an alkali solution of
a reducing compound, and oxidizing.
[0355] It is preferable that the catalyst (3) or (4) is obtained by
supporting a ruthenium halide on a carrier, treating the supported
one by using a reducing compound, and oxidizing.
[0356] It is preferable that the catalyst (3) or (4) is obtained by
supporting a ruthenium halide on a carrier, treating the supported
one by using an alkali solution of a reducing compound, and
oxidizing.
[0357] The catalyst produced by the process (5) for producing a
catalyst of the present invention is a supported ruthenium oxide
catalyst containing ruthenium oxide only at an outer surface layer,
not less than 80% of the outer surface of said catalyst satisfying
the following expression (1):
S/L<0.35 (1)
[0358] wherein L is a distance between a point (A) and a point (B),
said point (B) being a point formed on the surface of a catalyst
when a perpendicular line dropped from any point (A) on the surface
of the catalyst to the inside of the catalyst goes out from the
catalyst at the opposite side of the point (A), and S is a distance
between the point (A) and a point (C), said point (C) being a point
on the perpendicular line where ruthenium oxide does not exist.
[0359] Furthermore, preferably, S/L <0.30.
[0360] That is, as defined in the above formula (1), the catalyst
of the present invention substantially contains ruthenium oxide
only at an outer surface shell layer, and does not contain
ruthenium oxide in the inside of the catalyst. By adopting such a
structure, the activity per unit weight of ruthenium contained in
the catalyst can be enhanced.
[0361] The structure of the catalyst of the present invention will
be described specifically by using a cross sectional view of the
catalyst.
[0362] The case where the catalyst has a spherical shape is as
shown in FIG. 1. L corresponds to a diameter passing through a
center of a sphere and S corresponds to a thickness of an outer
surface shell layer of a sphere containing ruthenium oxide.
[0363] The case where the catalyst has a columnar shape is as shown
in FIG. 2.
[0364] The case where the catalyst has a cylindrical tablet is as
shown in FIG. 3.
[0365] The catalyst of the present invention may have a shape other
than that described above.
[0366] The process for producing the catalyst explained below is
preferable to obtain a catalyst suited for the above conditions.
Particularly, preferably the catalyst is prepared so as to satisfy
the above formula (1) by preliminarily supporting an alkali on a
carrier to be used, supporting a specific ruthenium compound, and
forming a precipitate of a ruthenium compound on the outer surface
of the carrier by the acid-base reaction.
[0367] The process of confirming that the catalyst satisfies the
above formula (1) includes a process of cutting along the plane
passing through the center of the particles of the supported
ruthenium oxide catalyst and measuring by using a magnifying glass
having graduation, and a process of cutting in the same manner and
measuring by using X-ray microanalyser (Electron probe micro
analyzer) (EPMA) Since the ruthenium component is fixed to the
carrier by forming a precipitate of a ruthenium compound on the
carrier and drying, the ruthenium component does not transfer
largely in the step of preparing the catalyst. Therefore, the
thickness of the ruthenium oxide layer is determined by measuring
the thickness of the layer supporting the ruthenium compound at the
stage where the ruthenium compound forms a precipitate on the
carrier and dried.
[0368] The catalyst of the present invention is produced by
supporting an alkali on a carrier, supporting at least one
ruthenium compound selected from the group consisting of ruthenium
halide, rutheniumoxy chloride, ruthenium-acetonato complex,
ruthenium organic acid salt and ruthenium-nitrosyl complex,
treating the supported one by using a reducing agent, and
oxidizing. By using these steps, the activity of the catalyst can
be enhanced.
[0369] The carrier includes oxides and mixed oxides of elements,
such as titanium oxide, alumina, zirconium oxide, silica, titanium
mixed oxide, zirconium mixed oxide, aluminum mixed oxide, silicon
mixed oxide and the like. Preferable carriers are titanium oxide,
alumina, zirconium oxide and silica, and more preferable carrier is
titanium oxide. A weight ratio of ruthenium oxide to the carrier is
usually within a range from 0.1/99.9 to 20.0/80.0, preferably from
0.5/99.5 to 15.0/85.0, and more preferably from 1.0/99.0 to
15.0/85.0. When the proportion of the ruthenium oxide is too low,
the activity is lowered sometimes. On the other hand, when the
proportion of ruthenium oxide is too high, the price of the
catalyst becomes high sometimes. Examples of the ruthenium oxide to
be supported include ruthenium dioxide, ruthenium hydroxide and the
like.
[0370] The process of supporting ruthenium oxide on a carrier at
the outer surface will be explained below. That is, the present
inventors have found that ruthenium oxide can be satisfactorily
supported on a carrier such as titanium oxide at the outer surface
by using an alkali preliminary impregnation process described below
and, therefore, the example of procedure will be explained by way
of the preparation example. That is, first, a carrier of titanium
oxide having a suitable particle diameter is impregnated with an
aqueous solution of an alkali metal hydroxide such as potassium
hydroxide or an alkali such as ammonium carbonate and ammonium
hydrogencarbonate. In this case, a thickness of a layer of a
ruthenium compound at the surface to be supported on the carrier is
decided by changing the kind of the alkali, concentration of the
alkali, amount of ruthenium compound to be supported, and time from
impregnation with ruthenium compound to drying. For example, when
using potassium hydroxide, a thickness of a layer to be impregnated
with the ruthenium compound can be changed by changing the
concentration of the aqueous solution within a range from 0.1 N to
2.0 N. Then, the carrier is impregnated with an aqueous solution of
an alkali and the carrier is dried. Then, the carrier is
impregnated with a solution of ruthenium chloride. As the solution,
an aqueous solution, a solution of an organic solvent such as
alcohol, or a mixed solution of water and an organic solvent is
used, but a solution of an organic solvent such as ethanol is
preferred. Then, the carrier impregnated with the ruthenium
compound is dried and hydrolyzed by using an alkali to form
ruthenium hydroxide, which is converted into ruthenium oxide.
Alternatively, the supported ruthenium compound is reduced to form
metal ruthenium, which is oxidized to form ruthenium oxide.
[0371] The alkali used preferably in the step of impregnating the
carrier with an aqueous solution of an alkali includes potassium
hydroxide, sodium hydroxide, ammonium carbonate and ammonium
hydrogencarbonate. The concentration of the alkali with which the
carrier is impregnated is usually from 0.01 to 4.0 N, and
preferably from 0.1 to 3.0 N. When the time from impregnation of
ruthenium compound with the carrier, which is impregnated with the
alkali, to drying is long, the inside of the carrier is impregnated
with ruthenium compound and, therefore, a suitable time must be
selected according to the kind and concentration of the alkali to
be used. Usually, the support is dried immediately after
impregnation, or dried until 120 minutes after impregnation.
Preferably, the catalyst is dried immediately after impregnation,
or dried until 30 minutes after impregnation.
[0372] The ruthenium compound to be supported on the carrier
include halide of ruthenium, for example, ruthenium chloride such
as RuCl.sub.3 and RuCl.sub.3 hydrate and ruthenium bromide such as
RuBr.sub.3 and RuBr.sub.3 hydrate; rutheniumoxy chloride such as
Ru.sub.2OCl.sub.4, Ru.sub.2OCl.sub.5 and Ru.sub.2OCl.sub.6;
[Ru(CH.sub.3COCHCOCH.sub.3)3] ruthenium-acetylacetonato complex;
ruthenium organic acid salt such as
[Ru.sub.3O(OCOCH.sub.3).sub.6(H.sub.2O).sub.3]OCOCH.sub.3 hydrate
and Ru.sub.2(RCOO).sub.4Cl(R: alkyl group having carbon atoms of
1-3); and ruthenium-nitrosyl complex such as
[Ru(NH.sub.3).sub.5(NO)]Cl.sub.13, [Ru(OH) (NH.sub.3).sub.4(NO)]
(NO.sub.3).sub.2 and Ru(NO) (NO.sub.3).sub.3. Preferable ruthenium
compounds are ruthenium halide, for example, ruthenium chloride
such as RuCl.sub.3 and RuCl.sub.3 hydrate and ruthenium bromide
such as RuBr.sub.3 and RuBr.sub.3 hydrate. More preferred one is a
ruthenium chloride hydrate.
[0373] Then, the embodiment of the process for preparing a
supported ruthenium oxide catalyst will be described. That is, a
process of hydrolyzing a supported ruthenium by using an alkali
such as aqueous solution of an alkali metal hydroxide to form
ruthenium hydroxide, and oxidizing to form ruthenium oxide, and a
process of reducing a supported ruthenium compound to form metal
ruthenium, and oxidizing to form ruthenium oxide are exemplified.
Now a process of reducing a ruthenium compound will be illustrated.
The process of reducing a ruthenium compound includes a process of
heating under a hydrogen gas flow, a process of performing wet
reduction by using hydrazine, formaldehyde and sodium boron hydride
and a process of reducing by using lithium boron halide, potassium
boron halide, lithium tri-sec-butyl-boron halide, sodium
tri-sec-butyl-boron halide, potassium tri-sec-butyl-boron halide,
lithium aluminum hydride, diisobutylaluminum hydride, sodium
hydride and potassium hydride. Now the process using sodium boron
hydride (NaBH.sub.4) will be illustrated. That is, a ruthenium
compound is supported on the above-mentioned carrier, dried and
then dipped in a solution of sodium boron hydride. The solution
includes aqueous solution, and solution of an organic solution such
as alcohol. A mixed solution of water and an organic solvent can
also be used. After wet reduction is conducted by using the
above-mentioned solution, the reduced one is washed with water and
then dried. Then, the carrier supporting ruthenium is oxidized to
form ruthenium oxide. A process using an oxidizing agent and a
process of calcining under air can be used. It is also preferable
process that a process of impregnating a ruthenium supported one
with an aqueous alkali metal chloride solution, drying the
impregnated one, and calcining under air to form ruthenium oxide.
In this case, a supported ruthenium oxide catalyst can be prepared
by washing the remained alkali metal chloride with water, and
drying.
[0374] The amount of the ruthenium compound with which the carrier
is impregnated is usually the same amount as that of the ruthenium
compound, which corresponds to the already described preferable
amount of ruthenium oxide to be supported.
[0375] The reducing agent used in the case of reducing the
supported ruthenium compound includes various reducing agents. When
using sodium boron hydride (NaBH.sub.4), it is preferably used in
the form of a solution. The concentration is usually from 0.05 to
20% by weight, and preferably from 0.1 to 10% by weight. A molar
ratio of sodium boron hydride to the supported ruthenium compound
is usually from 1.0 to 30, and preferably from 2.0 to 15.
[0376] Then, a process for preparing a supported ruthenium oxide
catalyst by oxidizing the resulting supported metal ruthenium
catalyst after reduction will be illustrated. Now the process of
calcining under air is illustrated. It is a preferable preparation
example that the supported metal ruthenium is oxidized by calcining
under gas containing oxygen in the presence of an alkali metal salt
to form highly active supported ruthenium oxide. As the gas
containing oxygen, an air is usually used.
[0377] The calcination temperature is usually from 100 to
600.degree. C., and preferably from 280 to 450.degree. C. When the
calcination temperature is too low, metal ruthenium particles are
remained in a large amount and, therefore, the activity of the
catalyst becomes insufficient sometimes. On the other hand, when
the calcination temperature is too high, agglomeration of ruthenium
oxide particles occur and, therefore, the activity of the catalyst
is lowered. The calcination time is preferably from 30 minutes to
10 hours.
[0378] In this case, it is preferred to calcine in the presence of
an alkali metal salt. By using this process, it is possible to
obtain higher activity of the catalyst because that process can
forming more fine particles of ruthenium oxide comparing the
process which include calcining in the substantially absence of the
alkali metal salt.
[0379] The alkali metal salt includes potassium chloride and sodium
chloride. Among them, potassium chloride and sodium chloride are
preferred, and potassium chloride is more preferred.
[0380] A molar ratio of the alkali metal salt to ruthenium is
preferably from 0.01 to 10, and more preferably from 0.1 to 5. When
the amount of the alkali metal salt to be used is too small,
sufficiently highly active catalyst is not obtained. On the other
hand, when the amount of the alkali metal salt is too small, the
industrial cost becomes high.
[0381] By the calcination, metal ruthenium supported on the carrier
is converted into a supported ruthenium oxide catalyst. It can be
confirmed by analysis such as X-ray diffraction and XPS (X-ray
photoelectron spectroscopy) that the metal ruthenium was converted
into ruthenium oxide. Incidentally, substantially total amount of
the metal ruthenium is preferably converted into ruthenium oxide,
but the metal ruthenium can be remained as far as the effect of the
present invention is not adversely affected.
[0382] It is also possible to obtain chlorine by oxidizing hydrogen
chloride with oxygen using the catalyst of the present invention.
The reaction system used to obtain chlorine includes, for example,
flow system such as fixed bed or fluidized bed, and a gas phase
reaction such as fixed bed flow system and gas phase fluidized bed
flow system can be preferably used. The fixed bed system has an
advantage that separation between the reaction gas and catalyst is
not required and that high conversion can be accomplished because a
raw gas can be sufficiently contacted with a catalyst. The
fluidized bed system has an advantage that heat in the reactor can
be sufficiently removed and temperature distribution width in the
reactor can be minimized.
[0383] When the reaction temperature is high, volatilization of
ruthenium oxide in a highly oxidized state occurs. Therefore, the
reaction is preferably conducted at low temperature and the
reaction temperature is usually from 100 to 500.degree. C.,
preferably from 200 to 400.degree. C., more preferably from 200 to
380.degree. C. The reaction pressure is usually from about
atmospheric pressure to 50 atm. As the raw material of oxygen, an
air may be used as it is, or pure oxygen may also be used. Since
other components are also discharged simultaneously when an inert
nitrogen gas is discharged out of the plant , pure oxygen
containing no inert gas is preferable. The theoretic molar amount
of oxygen based on hydrogen chloride is 1/4 mol, but oxygen is
usually fed in an amount that is 0.1-10 times of the theoretical
amount. In the case of the fixed bed gas phase flow system, the
amount of the catalyst to be used is usually from about 10 to 20000
h.sup.-1 in terms of a ratio (GHSV) to a feed rate of hydrogen
chloride as the raw material under atmospheric pressure. GHSV means
gas hourly space velocity which is a ratio of a volume of feed
hydrogen chloride gas (1/h) to volume of catalyst (1).
[0384] The present invention which relates to a supported ruthenium
oxide catalyst will be described below.
[0385] The supported ruthenium oxide of the present invention is a
supported ruthenium oxide catalyst using titanium oxide containing
not less than 20% of rutile titanium oxide as a carrier. As the
titanium oxide, for example, rutile titanium oxide, anatase
titanium oxide and non-crystal titanium oxide are known. The
titanium oxide containing rutile titanium oxide used in the present
invention refers to one containing a rutile crystal by measuring a
ratio of the rutile crystal to the anatase crystal in the titanium
oxide by using X-ray diffraction analysis. The measuring process
was described in detail in this invention which relates to a
process for producing chlorine and a process for producing a
supported ruthenium oxide catalyst. When the chemical composition
of the carrier used in the present invention is composed of
titanium oxide alone, the proportion of the rutile crystal is
determined from a ratio of the rutile crystal to the anatase
crystal in the titanium oxide by using X-ray diffraction analysis.
In the present invention, a mixed oxide of the titanium oxide and
other metal oxide is also used. In that case, the proportion of the
rutile crystal is determined by the following process. The oxide to
be mixed with the titanium oxide includes oxides of elements, and
preferred examples thereof include alumina, zirconium oxide and
silica. The proportion of the rutile crystal in the mixed oxide is
also determined from the ratio of the rutile crystal to the anatase
crystal in the titanium oxide by using X-ray diffraction analysis,
but it is necessary to contain the rutile crystal. In this case,
the content of the oxide other than the titanium oxide in the mixed
oxide is within a range from 0 to 60% by weight. Preferred carrier
includes titanium oxide which does not contain a metal oxide other
than titanium oxide.
[0386] The catalyst activity increases higher as the content of
rutile crystal in titanium oxide becomes larger because the
catalyst activity of the ruthenium oxide supported on rutile
crystal titanium oxide is higher than the catalyst activity of the
ruthenium oxide supported on anatase crystal or non-crystal
titanium oxide
[0387] It is necessary that the titanium oxide contains not less
than 20% of the rutile crystal. The content of the rutile crystal
is preferably not less than 30%, more preferably not less than 80%,
and most preferably not less than 90%.
[0388] The process for preparing the titanium oxide containing the
rutile crystal includes various processes and described in this
invention which relates to a process for producing chlorine and a
process for producing a supported ruthenium oxide catalyst.
[0389] The process of determining the proportion of the rutile
crystal in the titanium oxide includes a X-ray diffraction
analysis. The carrier used in the present invention is one having
both of a diffraction peak intensity of the rutile crystal and a
diffraction peak of the anatase crystal. The carrier includes one
wherein a proportion of the peak intensity of the rutile crystal to
the total of the peak intensity of the rutile crystal and the peak
intensity of the anatase crystal is not less than 20%, and
preferably not less than 30%.
[0390] The catalyst activity can be increased by the optimization
of the content of OH group contained in a carrier when the
supported ruthenium oxide catalyst on the titanium oxide containing
not less than 20% of rutile titanium oxide is used in the oxidation
reaction.
[0391] It is generally known that a hydroxyl group represented by
OH bound to Ti exists on the surface of the titanium oxide. The
titanium oxide used in the present invention is one containing an
OH group. And the process of measuring the content of OH group was
described in this invention which relates to a process for
producing chlorine and a process for producing a supported
ruthenium oxide catalyst. When the chemical composition of the
carrier used in the present invention is composed of titanium oxide
alone, it is determined from the content of the OH group in the
titanium oxide. In the present invention, a mixed oxide of the
titanium oxide and other metal oxide is also contained. The oxide
to be mixed with the titanium oxide includes oxides of elements,
and preferred examples thereof include alumina, zirconium oxide and
silica. In that case, the content of the oxide other than the
titanium oxide in the mixed oxide is within a range from 0 to 60%
by weight. Preferred carrier is titanium oxide which does not
contain the metal oxide other than the titanium oxide.
[0392] When the content of the OH group of the carrier is large,
the carrier and supported ruthenium oxide may react each other,
resulting in deactivation. On the other hand, when the content of
the OH group of the carrier is small, the activity of the catalyst
is lowered sometimes by sintering of the supported ruthenium oxide
and the other phenomenon.
[0393] That is, in the range of the content of OH group, the
catalyst activity increases to show the peak and decreases as the
content of OH group increases wherein the content of OH group has
appropriate range corresponding to the amount of the ruthenium
compound for supporting. Thus, the catalyst shows a high activity
in the appropriate range of the content of OH group. The content of
the OH group, which is used in the catalyst, is usually from
0.1.times.10.sup.-4 to 30.times.10.sup.-4 (mol/g-carrier),
preferably from 0.2.times.10.sup.-4 to 20.times.10.sup.-4
(mol/g-carrier), and more preferably from 3.0.times.10.sup.-4 to
10.times.10.sup.-4 (mol/g-carrier).
[0394] The process of adjusting the amount of the OH group
contained in the titanium oxide carrier to a predetermined amount
was described in this invention which relates to a process for
producing chlorine and a process for producing a supported
ruthenium oxide catalyst.
[0395] The present invention relates to a supported ruthenium oxide
catalyst supported on the above carrier, and a weight ratio of
ruthenium oxide to the carrier is usually within a range from
0.1/99.9 to 20.0/80.0, preferably from 0.5/99.5 to 15.0/85.0, and
more preferably from 1.0/99.0 to 15.0/85.0. When the proportion of
ruthenium oxide is too low, the activity is lowered sometimes. On
the other hand, when the proportion of ruthenium oxide is too high,
the price of the catalyst becomes high sometimes. Examples of the
ruthenium oxide to be supported include ruthenium dioxide,
ruthenium hydroxide and the like.
[0396] The process for preparing the supported ruthenium oxide
catalyst by using the above carrier includes various processes.
[0397] The process for preparing the supported ruthenium oxide
catalyst of the present invention includes processes for preparing
the catalysts (1), (2) and (3) of the invention of the process for
producing chlorine.
[0398] As the ruthenium compound to be supported on a carrier,
compounds listed in the catalysts (1), (2) and (3) of the invention
of the process for producing chlorine can be similarly used.
[0399] As the reducing compound used for treating the ruthenium
compound supported on the carrier, compounds listed in the catalyst
(1) of the invention of the process for producing chlorine can be
used. As the reducing hydrogenated compound, compounds listed in
the catalyst (3) of the invention of the process for producing
chlorine can be used.
[0400] It is a preferable preparation process of catalyst that the
process comprises supporting ruthenium compound on a carrier,
treating by basic compounds. The above basic compounds can be used
as same as mentioned in the catalyst (1),(2) in this invention
which relates to a process for producing chlorine.
[0401] Specific examples of the process for preparing the supported
ruthenium oxide catalyst of the present invention includes process
explained in the portion in common with the catalysts (1) and (2)
of the invention of the process for producing chlorine and process
explained in the catalyst (3) of the invention of the process for
producing chlorine.
[0402] It is also possible to obtain chlorine by oxidizing hydrogen
chloride with oxygen using the above-mentioned catalyst. The
reaction system used to obtain chlorine was described in this
invention which relates to a process for producing chlorine and a
process for producing a supported ruthenium oxide catalyst.
[0403] As described above, according to the present invention,
there could be provided a process for producing chlorine by
oxidizing hydrogen chloride with oxygen, wherein said process can
produce chlorine by using a catalyst having high activity in a
smaller amount at a lower reaction temperature. There could also be
provided a process for producing chlorine by oxidizing hydrogen
chloride, wherein said process can facilitate control of the
reaction temperature by making it easy to remove the reaction heat
from catalyst bed by using a catalyst having good thermal
conductibility, which can be formed by containing a compound having
high thermal conductivity of a solid phase, and can achieve high
reaction conversion by keeping the whole catalyst bed at sufficient
temperature for industrially desirable reaction rate.
[0404] According to the present invention, there could also be
provided a process for producing a supported ruthenium oxide
catalyst, wherein said process is a process for producing a
catalyst having high activity and can produce a catalyst having
high activity capable of producing the desired compound by using a
smaller amount of the catalyst at a lower reaction temperature.
[0405] According to the present invention, there could also be
provided a supported ruthenium oxide catalyst, wherein said
catalyst has high activity and can produce the desired compound by
using a smaller amount of the catalyst at a lower reaction
temperature.
[0406] The following Examples further illustrate the present
invention in detail but are not to be construed to limit the scope
thereof.
EXAMPLE 1
[0407] A catalyst was prepared by the following process. That is,
0.81 g of commercially available ruthenium chloride
(RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by weight) was previously
dissolved in 6.4 g of pure water to prepare an aqueous solution,
and 20.0 g of a titanium oxide powder (P25, manufactured by Nippon
AEROSIL Co., Ltd.) was impregnated with this solution. Then, the
impregnated powder was dried at 60.degree. C. for 2 hours. After
drying, the powder was sufficiently ground in a mortar to obtain
20.3 g of a dark green powder. According to the same manner as that
described above, the same operation was repeated nine times to
obtain 183.8 g of a dark green powder.
[0408] Then, 10.4 g of this powder was dipped in a mixed solution
of 2.1 g of a potassium hydroxide solution adjusted to 2N and 30.1
g of pure water in a ultrasonic cleaner at room temperature for 1
minute. In a suspension of the dipped one and the solution, a
solution of 0.61 g of a hydrazine monohydrate and 5.0 g of pure
water was poured under nitrogen at room temperature with applying
an ultrasonic wave. At the time of pouring, bubbling was observed
in the solution. After the solution was allowed to stand for 15
minutes until the bubbling disappeared, the supernatant was
separated by filtration. 500 ml of pure water was added, followed
by washing for 30 minutes and further separation by filtration.
This operation was repeated five times. The pH of the wash at the
first time was 9.1, and the pH of the wash at the fifth time was
7.4. To the powder separated by filtration, a 2 mol/l potassium
chloride solution was added and, after stirring, the powder was
separated by filtration again. This operation was repeated three
times. The amount of the potassium chloride solution added was 54.4
g at the first time, 52.1 g at the second time and 52.9 g at the
third time, respectively. The procedure from the operation of
dipping in the potassium hydroxide solution was repeated six times
in the same manner to obtain 107 g of a cake. 53.1 g of the
resulting cake was dried at 60.degree. C. for 4 hours to obtain
34.1 g of a gray powder. After heating from room temperature to
350.degree. C. under air over 1 hour, the powder was calcined at
the same temperature for 3 hours. After the completion of the
calcination, 500 ml of pure water was added and the mixture was
stirred and, furthermore, the powder was separated by filtration.
This operation was repeated twenty-one times and, after adding
dropwise an aqueous silver nitrate solution to the wash, it was
confirmed that potassium chloride is not remained. Then, 28.0 g of
a bluish gray powder was obtained by drying this powder at
60.degree. C. for 4 hours. The resulting powder was molded to
adjust the particle size to 8.6-16.0 mesh, thereby obtaining a
ruthenium oxide catalyst supported on titanium oxide.
[0409] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=1.9% by weight
[0410] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=1.5% by weight
[0411] X-ray diffraction analysis of the titanium oxide powder used
was conducted under the following conditions.
[0412] Apparatus: Rotaflex RU200B (manufactured by Rigaku Co.)
[0413] X-ray type: Cu K .alpha.
[0414] X-ray output: 40 kV-40 mA
[0415] Divergence slit: 1.degree.
[0416] Scattering slit: 1.degree.
[0417] Receiving slit: 0.15 mm
[0418] Scanning speed: 1.degree./min.
[0419] Scanning speed: 5.0-75.0.degree.
[0420] Monochromator: curved crystal monochromator is used
[0421] The proportion of a peak intensity (381cps) of a rutile
crystal (2.theta.=27.4.degree.) to a total value of a peak
intensity (381 cps) of a rutile crystal (.sup.-) and a peak
intensity (1914 cps) of an anatase crystal (2.theta.=25.3.degree.)
was 17%. Consequently, the content of the rutile crystal was
17%.
[0422] The ruthenium oxide catalyst supported on titanium oxide
(17.8 g) thus obtained was charged separately in two zones of the
same glass reaction tube. The inner diameter of the glass reaction
tube was 15 mm and a thermocouple protective tube having an outer
diameter of 6 mm was inserted therein. In the upper zone, the
catalyst was charged after diluting by sufficiently mixing 5.9 g of
the ruthenium oxide catalyst supported on titanium oxide with 23.6
g of a commercially available spherical (2 mm in size)
.alpha.-alumina carrier (SSA995, manufactured by Nikkato Co.). In
the lower zone, 11.9 g of the ruthenium oxide catalyst supported on
titanium oxide was charged without being diluted. A hydrogen
chloride gas (96 ml/min.) and an oxygen gas (53 ml/min.) were
respectively supplied by passing from the top to the bottom of the
reactor under atmospheric pressure (in terms of 0.degree. C., 1
atm). The upper zone of the glass reaction tube was heated in an
electric furnace to adjust the internal temperature (hot spot) to
361.degree. C. Similarly, the lower zone was heated to adjust the
internal temperature (hot spot) to 295.degree. C. 4.5 Hours after
the beginning of the reaction, the gas at the reaction outlet was
sampled by passing it through an aqueous 30% potassium iodide
solution, and then the amount of chlorine formed and amount of the
non-reacted hydrogen chloride were respectively determined by
iodometric titration and neutralization titration. As a result, the
conversion of hydrogen chloride was 93.0%.
[0423] According to the same reaction manner as that described
above except that the hydrogen chloride gas (146 ml/min.) and the
oxygen gas (74 ml/min.) were respectively supplied under
atmospheric pressure (in terms of 0.degree. C., 1 atm) and that the
internal temperature of the upper zone was adjusted to 360.degree.
C. and the internal temperature of the lower zone was adjusted to
300.degree. C., the reaction was conducted. 4.5 Hours after the
beginning of the reaction, the conversion of hydrogen chloride was
91.6%.
EXAMPLE 2
[0424] A catalyst was prepared by the following process. That is,
3.52 g of commercially available ruthenium chloride
(RuCl.sub.3.nH.sub.2O, Ru content: 35.5% by weight)was dissolved in
7.61 g of water, followed by sufficient stirring to obtain an
aqueous ruthenium chloride solution. The resulting aqueous solution
was added dropwise in 25.0 g of a spherical (1-2 mm .phi. in size)
titanium oxide carrier (CS-300S-12, anatase crystal manufactured by
Sakai Chemical Industry Co., Ltd.), thereby to support ruthenium
chloride by impregnation. The supported one was dried in an air at
60.degree. C. for 4 hours to obtain 28.0 g of a ruthenium chloride
supported on titanium oxide. 4.0 g of the resulting ruthenium
chloride supported on titanium oxide (28.0 g) was dipped in a mixed
solution of 2.4 g of an aqueous potassium hydroxide solution
adjusted to 2 mol/l and 1.2 g of pure water at room temperature for
1 minute. Then, the dipped one was poured, together with the
solution, into 0.67 g of a hydrazine monohydrate under nitrogen at
room temperature. At the time of pouring, bubbling was observed in
the solution. After the solution was allowed to stand for about 15
minutes until the bubbling disappeared, 4.0 g of pure water was
poured, followed by stirring. Then, the supernatant was removed by
decantation. Then, 30 ml of an aqueous potassium chloride solution
adjusted to 2 mol/l was poured and, after stirring, the supernatant
was removed by decantation. By repeating this operation six times,
washing with the aqueous potassium chloride solution was conducted.
Then, the washed one was dried under air at 60.degree. C. for 4
hours to obtain a spherical gray solid containing potassium
chloride.
[0425] Then, the solid was heated under air from room temperature
to 350.degree. C. for about 1 hour and then calcined at the same
temperature for 3 hours to obtain a spherical solid. Washing was
conducted by adding 0.5 liter of pure water to the resulting solid,
stirring and allowing to stand 30 minutes, and the resulting solid
was separated by filtration. This operation was repeated four
times. The washing time was about 4 hours. The washed one was dried
under air at 60.degree. C. for 4 hours to obtain 3.73 g of a black
spherical ruthenium oxide catalyst supported on titanium oxide.
[0426] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
Ru.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.1% by weight
[0427] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0428] The ruthenium oxide catalyst supported on titanium oxide
(2.5 g) thus obtained was diluted by mixing with a 5 g of spherical
titanium oxide carrier (1.about.2 mm .phi. in size) and then
charged in a quartz reaction tube (inner diameter: 12 mm). A
hydrogen chloride gas (192 ml/min.) and an oxygen gas (184 ml/min.)
were respectively supplied under atmospheric pressure (in terms of
0.degree. C., 1 atm). The quartz reaction tube was heated in an
electric furnace to adjust the internal temperature (hot spot) to
300.degree. C. 1.8 Hours after the beginning of the reaction, the
gas at the reaction outlet was sampled by passing it through an
aqueous 30 wt % potassium iodide solution, and then the amount of
chlorine formed and amount of the non-reacted hydrogen chloride
were respectively determined by iodometric titration and
neutralization titration.
[0429] The formation activity of chlorine per unit weight of the
catalyst determined by the following equation was
3.68.times.10.sup.-4 mol/min.g-catalyst.
[0430] Chlorine formation activity per unit weight of catalyst
(mol/min.g-catalyst)=amount of outlet chlorine formed
(mol/min)/weight of catalyst (g)
[0431] The formation activity of chlorine per unit weight of Ru
determined by the following equation was 78.4.times.10.sup.-4
mol/min.g-Ru.
[0432] Chlorine formation activity per unit weight of Ru
(mol/min.g-Ru)=amount of outlet chlorine formed (mol/min)/weight of
Ru (g)
EXAMPLE 3
[0433] A catalyst was prepared by the following process. That is,
3.52 g of commercially available ruthenium chloride
(RuCl.sub.3.nH.sub.2O, Ru content: 35.5% by weight) was dissolved
in 7.6 g of water, followed by sufficient stirring to obtain an
aqueous ruthenium chloride solution. The resulting aqueous solution
was added dropwise in 25.0 g of a spherical (1-2 mm .phi. in size)
titanium oxide carrier (CS-300S-12, manufactured by Sakai Chemical
Industry Co., Ltd.), thereby to support ruthenium chloride by
impregnation. The supported one was dried under air at 60.degree.
C. for 4 hours to obtain 28.1 g of a ruthenium chloride supported
on titanium oxide. 4.0 g of the resulting ruthenium chloride
supported on titanium oxide (28.1 g) was dipped in a mixed solution
of 2.4 g of an aqueous potassium hydroxide solution adjusted to 2
mol/l and 1.2 g of pure water at room temperature for 1 minute.
Then, the dipped one was poured, together with the solution, into
0.67 g of a hydrazine monohydrate under nitrogen at room
temperature. At the time of pouring, bubbling was observed in the
solution. After the solution was allowed to stand for about 15
minutes until the bubbling disappeared, 30 ml of pure water was
poured, followed by stirring. Then, the supernatant was removed by
decantation. By repeating this operation six times, washing with
water was conducted. Then, the washed one was dried under air at
60.degree. C. for 4 hours. The dried solid was impregnated with 1.3
g of an aqueous potassium hydroxide solution adjusted to 1.4 mol/l,
and then dried under air at 60.degree. C. for 0.5 hours to obtain a
spherical gray solid containing potassium chloride.
[0434] The calculated value of a molar ratio of potassium chloride
to ruthenium was 1.0. Then, the solid was heated under air from
room temperature to 350.degree. C. for about 1 hour and then
calcined at the same temperature for 3 hours to obtain a spherical
solid. Washing was conducted by adding 0.5 1 of pure water to the
resulting solid and filtering. This operation was repeated four
times. The washing time was about 4 hours. The washed one was dried
under air at 60.degree. C. for 4 hours to obtain 3.65 g of a black
spherical ruthenium oxide catalyst supported on titanium oxide.
[0435] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.1% by weight
[0436] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0437] The ruthenium oxide catalyst supported on titanium oxide
(2.5 g) thus obtained was charged in a quartz reaction tube (inner
diameter: 12 mm) in the same manner as that described in Example 2,
and then the reaction was conducted according to the same reaction
manner as that described in Example 2. 1.8 Hours after the
beginning of the reaction, the formation activity of chlorine per
unit weight of the catalyst was 3.63.times.10.sup.-4
mol/min.g-catalyst.
[0438] The formation activity of chlorine per unit weight of the Ru
was 77.3.times.10.sup.-4 mol/min.g-Ru.
EXAMPLE 4
[0439] A catalyst was prepared by the following process. That is,
50.0 g of a titanium oxide powder (STR-60N, 100% rutile crystal ,
manufactured by Sakai Chemical Industry Co., Ltd.) was kneaded with
33.4 g of pure water and 6.6 g of a titanium oxide sol (CSB,
TiO.sub.2 content: 38% by weight, manufactured by Sakai Chemical
Industry Co., Ltd.). At room temperature, a dry air was blown to
the kneaded one, which was then dried until suitable viscosity was
obtained. The weight loss of water by drying was 0.2 g. After
drying, the mixture was sufficiently kneaded again. The kneaded one
was extruded into a form of a noodle of 1.5 mm .phi. in size. After
drying under air at 60.degree. C. for 4 hours, 46.3 g of a white
noodle-shaped titanium oxide was obtained. After heating under air
from room temperature to 500.degree. C. over 1.3 hours, calcination
was conducted at the same temperature for 3 hours. After the
completion of the calcination, 45.3 g of a white extruded titanium
oxide carrier was obtained by cutting the noodle-shaped solid into
pieces of about 5 mm in size. Then, 40.0 g of this carrier was
impregnated with an aqueous solution prepared by dissolving 3.23 g
of commercially available ruthenium chloride (RuCl.sub.3.nH.sub.2O,
Ru content: 37.3% by weight) in 21.9 g of pure water, and dried at
60.degree. C. for 2 hours. Then, the resulting solid was dipped in
a solution of 16.7 g of a 2N potassium hydroxide solution, 241 g of
pure water and 4.1 g of hydrazinemonohydrate under nitrogen at room
temperature, with stirring every 15 minutes. Bubbling occurred on
dipping. After 80 minutes, filtration was conducted by using a
glass filter. Washing was conducted for 30 minutes by adding 500 ml
of water, followed by filtration. This-operation was repeated five
times. The pH of the wash was 9.2 at the first time, and the pH of
the wash was 7.2 at the fifth time. To the extruded solid separated
by filtration, 50 g of a 0.5 mol/l of potassium chloride solution
was added and, after stirring, the extruded solid was separated by
filtration again. This operation was repeated three times. The
resulting solid was dried at 60.degree. C. for 4 hours to obtain a
gray solid. After heating from room temperature to 350.degree. C.
in an air over 1 hour, the solid was calcined at the same
temperature for 3 hours. After the completion of the calcination,
500 ml of pure water was added and the mixture was stirred and,
furthermore, the solid was separated by filtration. This operation
was repeated ten times and, after adding dropwise an aqueous silver
nitrate solution to the wash, it was confirmed that potassium
chloride is not remained. Then, 41.1 g of a bluish gray extruded
ruthenium oxide catalyst supported on titanium oxide was obtained
by drying this solid at 60.degree. C. for 4 hours.
[0440] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=3.8% by weight
[0441] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=2.9% by weight
[0442] X-ray diffraction analysis of the titanium oxide powder
(STR-60N) used was conducted under the same conditions as those of
Example 1. As a result, a peak intensity of a rutile crystal
(2.theta.=27.40.degree.) was 1015 cps. On the contrary a anatase
crystal(2.theta.=25.3.degree.) peak was not detected. Consequently,
the content of the rutile crystal was 100%.
[0443] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.50 g of
the ruthenium oxide catalyst supported on titanium oxide thus
obtained with 10 g of a commercially available spherical (2 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the oxygen gas (192 ml/min.) was passed through the reaction
tube and the internal temperature was adjusted to 298.degree. C.,
the reaction was conducted. 2.3 Hours after the beginning of the
reaction, the formation activity of chlorine per unit weight of the
catalyst was 8.88.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 5
[0444] A catalyst was prepared by the following process. That is,
15.0 g of a titanium oxide powder (STR-60N, 100% rutile crystal ,
manufactured by Sakai Chemical Industry Co., Ltd.) was dipped in an
aqueous solution of 2.01 g of commercially available ruthenium
chloride (RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by weight) and
26.7 g of pure water, evaporated under reduced pressure at
50.degree. C. for 4 hours, and then dried at 60.degree. C. for 2
hours. After drying, the powder was sufficiently ground to obtain a
black powder. This powder was dipped in a solution of 10.4 g of a
2N potassium hydroxide solution, 69.9 of pure water and 2.53 g of
hydrazinemonohydrate undernitrogen at room temperature. Bubbling
occurred on dipping. The gas bubbled during the treatment for 1
hour was collected and the volume was measured. As a result, it was
74 ml in a normal state. The reduced powder was separated by
filtration. Washing was conducted for 30 minutes by adding 500 ml
of water, followed by filtration. This operation was repeated five
times. The pH of the wash was 9.4 at the first time, and the pH of
the wash was 7.1 at the fifth time. To the powder separated by
filtration, 50 g of a 2 mol/l of potassium chloride solution was
added and, after stirring, the powder was separated by filtration
again. This operation was repeated three times. The resulting cake
was dried at 60.degree. C. for 4 hours to obtain a blackish brown
powder. After heating from room temperature to 350.degree. C. in an
air over 1 hour, the solid was calcined at the same temperature for
3 hours. After the completion of the calcination, 500 ml of pure
water was added and the mixture was stirred and, furthermore, the
powder was separated by filtration. This operation was repeated
five times and, after adding dropwise an aqueous silver nitrate
solution to the wash, it was confirmed that potassium chloride is
not remained. Then, 14.5 g of a black powder was obtained by drying
this powder at 60.degree. C. for 4 hours. The resulting powder was
molded to adjust the particle size to 8.6-16.0 mesh, thereby
obtaining a ruthenium oxide catalyst supported on titanium
oxide.
[0445] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.2% by weight
[0446] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0447] X-ray diffraction analysis of the titanium oxide carrier
used was conducted under the same conditions as those of Example 1.
As a result, The proportion of a peak intensity (1389cps) of a
rutile crystal (2.theta.=27.4.degree.) to a total value of a peak
intensity (1389 cps) of a rutile crystal and a peak intensity (40
cps) of an anatase crystal (2.theta.=25.3.degree.) was 97%.
Consequently, the content of the rutile crystal was 97%.
[0448] The content of the OH group of the carrier was measured in
the following manner. That is, a sample was previously dried in an
air at 150.degree. C. for 2 hours and cooled in a desiccator. Then,
1.06 g of the sample was transferred to the flask whose atmosphere
was replaced by nitrogen, and was suspended in 40 ml of a
dehydrated toluene solvent. To inhibit heat generation, the flask
was ice-cooled and 5 ml of methyl lithium was dropped from a
dropping funnel under nitrogen. As a result, 52 ml of a methane gas
was evolved. The same operation was conducted, except for using
toluene without charging no sample. As a result, 30 ml of a methane
gas was evolved. At this time, the temperature was 24.degree. C.
The content Q (mol/g-carrier) of the OH group was calculated by
using the following equation (1):
Q32 (V-V.sub.0)/(22400.times.(273+T)/273)/W (1)
[0449] where
[0450] V: amount of gas evolved (ml), volume of a methane gas
evolved at the temperature T during the measurement
[0451] V.sub.0: blank amount of gas evolved (ml), volume of a
methane gas evolved at the temperature T from remained water in the
measuring system when measuring without putting a sample
[0452] T: Measuring temperature (.degree. C.)
[0453] W: Amount of sample (g)
[0454] As a result, Q was 8.5.times.10.sup.-4 (mol/g-carrier).
[0455] Furthermore, the valence of Ru reduced was calculated from
the amount of nitrogen produced by the hydrazine treatment
according to the following scheme (2).
[0456] As a result, the following scheme was obtained. 3
[0457] In the present invention, the valence of ruthenium was
determined by the scheme (1).
[0458] The valence of Ru when the reaction (1) proceeds is
represented by the following equation:
Valence number of Ru=3-((V/22400.times.4)/N) (2)
[0459] where V: amount of gas produced (ml), N: amount of Ru
content which was charged (mol)
[0460] The valence number of Ru was calculated as 1.22.
[0461] Ru was reduced to the valence of 1.22.
[0462] On the other hand, in addition to the above reaction, there
is also known the reaction (3) represented by the following scheme:
4
[0463] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.5 g of
the ruthenium oxide catalyst supported on titanium oxide thus
obtained with 10 g of a commercially available spherical (2 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the oxygen gas (192 ml/min.) was passed through the reaction
tube, the reaction was conducted. 2.2 Hours after the beginning of
the reaction, the formation activity of chlorine per unit weight of
the catalyst was 5.10.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 6
[0464] A catalyst was prepared by the following process. That is,
5.0 g of a spherical (1-2 mm in size) titanium oxide carrier
(CS-300S-12, anatase crystal, manufactured by Sakai Chemical
Industry Co., Ltd.) was impregnated with a solution prepared
previously by dissolving 0.71 g of ruthenium chloride
(RuCl.sub.3.nH.sub.2O, Ru content: 35.5% by weight) in 1.7 g of
water, and then dried at 60.degree. C. for 2 hours. Then, a
solution of 0.84 g of sodium boron hydride (NaBH.sub.4), 4.1 g of
water and 22.1 g of ethanol was prepared. After the solution was
sufficiently cooled in an ice bath, an already prepared ruthenium
chloride supported on titanium carrier was added and ruthenium
chloride was reduced. At this time, bubbling was observed. After
the bubbling was terminated, the reduced solid was separated by
filtration. After washing with 500 ml of pure water for 30 minutes,
the solid was separated by filtration. This operation was repeated
five times. Then, this solid was dried at 60.degree. C. for 4
hours. As a result, 5.2 g of a black solid was obtained. Then, this
solid was impregnated with a solution prepared by dissolving 0.19 g
of potassium chloride in 3.1 g of pure water by two portions. The
impregnation amount of the potassium chloride solution was 1.7 g at
the first time. After drying at 60.degree. C. for 1 hour, the
amount was 1.4 g at the second time. The resulting solid was dried
at 60.degree. C. for 4 hours. The dried one was heated under air to
350.degree. C. over 1 hour and then calcined at the same
temperature for 3 hours. Then, the resulting solid was washed with
500 ml of pure water for 30 minutes and then separated by
filtration. This operation was repeated five times. After adding
dropwise an aqueous silver nitrate solution to the filtrate, it was
confirmed that potassium chloride is not remained. After washing,
the solid was dried 60.degree. C. for 4 hours to obtain 5.1 g of a
spherical black ruthenium oxide catalyst supported on titanium
oxide. The pore radius of the resulting catalyst was within a range
from 0.004 to 0.02 micrometer. The pore distribution curve of this
catalyst measured by a mercury porosimeter is shown in FIG. 7.
[0465] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.2% by weight
[0466] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2 +TiO.sub.2).times.100=4.7% by weight
[0467] X-ray diffraction analysis of the titanium oxide used was
conducted under the same conditions as those of Example 1. As a
result, a peak of a rutile crystal (2.theta.=27.4.degree.) was not
detected to a anatase crystal peak intensity (1824 cps,
2.theta.=25.3.degree.). Consequently, the content of the rutile
crystal was 0%.
[0468] Under the same conditions as those of Example 5 except that
the amount of the sample was 2.56 g and the amount of toluene was
40 ml, the content of the OH group of the carrier was measured. As
a result, 86 ml of a methane gas was evolved. The content of the OH
group of the carrier was 9.0.times.10.sup.-4 (mol/g-carrier).
[0469] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube and that the hydrogen chloride (187 ml/min.) and the oxygen
gas (199 ml/min.) were passed through the reaction tube, the
reaction was conducted. 2.0 Hours after the beginning of the
reaction, the formation activity of chlorine per unit weight of the
catalyst was 3.92.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 7
[0470] A catalyst was prepared by the following process. That is,
10.1 g of a titanium oxide powder (P25, manufactured by Nippon
AEROSIL Co., Ltd.) was impregnated with an aqueous solution
prepared previously by dissolving 0.41 of commercially available
ruthenium chloride (RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by
weight) in 3.5 g of pure water, and then dried at 60.degree. C. for
2 hours. After drying, the powder was sufficiently ground in a
mortar to obtain a dark green powder. To reduce this powder with
sodium boron hydride, a solution was prepared by dissolving 0.50 g
of sodium boron hydride in 100.0 g of ethanol and cooled in an ice
bath. To this sodium boron hydride solution, the total amount of
ruthenium chloride supported on titanium oxide was added with
stirring. Bubbling occurred on addition. After 1 hour, the
supernatant was removed by decantation. 500 ml of pure water was
added, followed by washing for 30 minutes and further separation by
filtration. This operation was repeated five times. The pH of the
wash at the first time was 9.3, and the pH of the wash at the fifth
time was 4.2. To the powder separated by filtration, a 2 mol/l
potassium chloride solution was added and, after stirring, the
powder was separated by filtration again. This operation was
repeated three times. The amount of the potassium chloride solution
added was 48.1 g at the first time, 52.9 g at the second time and
47.2 g at the third time, respectively. The resulting cake was
dried at 60.degree. C. for 4 hours to obtain a gray powder. After
heating from room temperature to 350.degree. C. under air over 1
hour, the powder was calcined at the same temperature for 3 hours.
After the completion of the calcination, 500 ml of pure water was
added and the mixture was stirred and, furthermore, the powder was
separated by filtration. This operation was repeated five times
and, after adding dropwise an aqueous silver nitrate solution to
the wash, it was confirmed that potassium chloride is not remained.
Then, 9.2 g of a bluish gray powder was obtained by drying this
powder at 60.degree. C. for 4 hours. The resulting powder was
molded to adjust the particle size to 8.6-16.0 mesh, thereby
obtaining a ruthenium oxide catalyst supported on titanium
oxide.
[0471] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=1.9% by weight
[0472] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=1.5% by weight
[0473] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube and that the hydrogen chloride (195 ml/min.) and the oxygen
gas (198 ml/min.) were passed through the reaction tube, the
reaction was conducted. 2.0 Hours after the beginning of the
reaction, the formation activity of chlorine per unit weight of the
catalyst was 5.56.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 8
[0474] A catalyst was prepared by the following process. That is,
10.1 g of a titanium oxide powder (P25, manufactured by Nippon
AEROSIL Co., Ltd.) was impregnated with an aqueous solution
prepared previously by dissolving 0.40 g of commercially available
ruthenium chloride (RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by
weight) in 3.4 g of pure water, and then dried at 60.degree. C. for
2 hours. After drying, the powder was sufficiently ground in a
mortar to obtain a dark green powder. The powder was dipped in a
solution of 2.1 g of a 2N potassium hydroxide solution and 30.2 g
of pure water, and then stirred with putting a flask in an
ultrasonic cleaner. After 1 minute, a solution of 0.59 g of
hydrazine monohydrate and 5.1 g of pure water were added to the
suspension under stirring at room temperature under nitrogen.
Bubbling occurred on addition. After 15 minutes, the reduced powder
was separated by filtration. To the resulting powder, 500 ml of
pure water was added, followed by washing for 30 minutes and
further separation by filtration. This operation was repeated five
times. The pH of the wash at the first time was 7.8, and the pH of
the wash at the fifth time was 6.0. To the powder separated by
filtration, a 2 mol/l potassium chloride solution was added and,
after stirring, the powder was separated by filtration again. This
operation was repeated three times. The amount of the potassium
chloride solution added was 53.6 g at the first time, 62.4 g at the
second time and 39.4 g at the third time, respectively. The
resulting cake was dried at 60.degree. C. for 4 hours to obtain a
beige powder. After heating from room temperature to 350.degree. C.
under air over 1 hour, the powder was calcined at the same
temperature for 3 hours. After the completion of the calcination,
500 ml of pure water was added and the mixture was stirred and,
furthermore, the powder was separated by filtration. This operation
was repeated five times and, after adding dropwise an aqueous
silver nitrate solution to the wash, it was confirmed that
potassium chloride is not remained. Then, 8.4 g of a bluish gray
powder was obtained by drying this powder at 60.degree. C. for 4
hours. The resulting powder was molded to adjust the particle size
to 8.6-16.0 mesh, thereby obtaining a ruthenium oxide catalyst
supported on titanium oxide.
[0475] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=1.9% by weight
[0476] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=1.4% by weight
[0477] X-ray diffraction analysis of the titanium oxide powder used
was conducted under the same conditions as those of Example 1. As a
result, the content of the rutile crystal was 17%.
[0478] Under the same conditions as those of Example 5 except that
the amount of the sample was 4.08 g and the amount of toluene was
80 ml, the content of the OH group of the carrier was measured. As
a result, 88 ml of a methane gas was evolved. The content of the OH
group of the carrier was 2.8.times.10.sup.-4 (mol/g-carrier).
[0479] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube and that the hydrogen chloride (187 ml/min.) and the oxygen
gas (199 ml/min.) were passed through the reaction tube and the
internal temperature was adjusted to 301.degree. C., the reaction
was conducted. 2.0 Hours after the beginning of the reaction, the
formation activity of chlorine per unit weight of the catalyst was
5.33.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 9
[0480] A catalyst was prepared by the following process. That is,
19.7 g of a titanium oxide powder (P25, manufactured by Nippon
AEROSILerogyl Co., Ltd.) was impregnated with an aqueous solution
prepared previously by dissolving 0.81 g of commercially available
ruthenium chloride (RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by
weight) in 6.0 g of pure water, and then dried at 60.degree. C. for
2 hours. After drying, the powder was sufficiently ground in a
mortar to obtain a dark green powder. To reduce this powder with
sodium boron hydride, a solution was prepared by dissolving 1.00 g
of sodium boron hydride in 200 g of ethanol and cooled in an ice
bath. To this sodium boron hydride solution, the total amount of
ruthenium chloride supported on titanium oxide was added with
stirring. Bubbling occurred on addition. After 1 hour, the
supernatant was removed by decantation. 500 ml of pure water was
added, followed by washing for 30 minutes and further separation by
filtration. This operation was repeated five times. The pH of the
wash at the first time was 9.8, and the pH of the wash at the fifth
time was 6.6. The resulting cake was dried at 60.degree. C. for 4
hours. As a result, 18.0 g of a bluish gray powder was obtained.
Then, the resulting powder was impregnated with an aqueous solution
of 0.66 g of potassium chloride and 9.0 g of pure water. The
resulting powder was dried at 60.degree. C. for 4 hours. After
heating from room temperature to 350.degree. C. under air over 1
hour, the powder was calcined at the same temperature for 3 hours.
After the completion of the calcination, 500 ml of pure water was
added and the mixture was stirred and, furthermore, the powder was
separated by filtration. This operation was repeated five times
and, after adding dropwise an aqueous silver nitrate solution to
the wash, it was confirmed that potassium chloride is not remained.
Then, 17.3 g of a bluish gray powder was obtained by drying this
powder at 60.degree. C. for 4 hours. The resulting powder was
molded to adjust the particle size to 8.6-16.0 mesh, thereby
obtaining a ruthenium oxide catalyst supported on titanium
oxide.
[0481] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=2.0% by weight
[0482] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=1.5% by weight
[0483] X-ray diffraction analysis of the titanium oxide powder used
was conducted under the same conditions as those of Example 1. As a
result, the content of the rutile crystal was 17%.
[0484] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube and that the hydrogen chloride (195 ml/min.) and the oxygen
gas (198 ml/min.) were passed through the reaction tube and the
internal temperature was adjusted to 299.degree. C., the reaction
was conducted. 2.0 Hours after the beginning of the reaction, the
formation activity of chlorine per unit weight of the catalyst was
4.41.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 10
[0485] A catalyst was prepared by the following process. That is, a
titanium oxide powder (STR-60N, 100% rutile crystal system,
manufactured by Sakai Chemical Industry Co., Ltd.) was previously
heated in an air from room temperature to 500.degree. C. over 1.4
hours and calcined at the same temperature for 3 hours. Then, 15.1
g of the calcined one was dipped in an aqueous solution of 0.61 g
of commercially available ruthenium chloride (RuCl.sub.3.nH.sub.2O,
Ru content: 37.3% by weight) and 26.7 g of pure water, evaporated
under reduced pressure at 50.degree. C. for 4 hours, and then dried
at 60.degree. C. for 2 hours. After drying, the powder was
sufficiently ground to obtain a dark green powder. This powder was
dipped in a solution of 3.2 g of a 2N potassium hydroxide solution,
52.6 of pure water and 0.77 g of hydrazine monohydrate at room
temperature under nitrogen. Bubbling occurred on dipping. After 1
hour, the reduced powder was separated by filtration. To the
resulting powder, 500 ml of pure water was added, followed by
washing for 30 minutes and further separation by filtration. This
operation was repeated seven times. The pH of the wash was 9.9 at
the first time, and the pH of the wash was 7.5 at the seventh time.
To the powder separated by filtration, 50 g of a 2 mol/l of
potassium chloride solution was added and, after stirring, the
powder was separated by filtration again. This operation was
repeated three times. The resulting solid was dried at 60.degree.
C. for 4 hours to obtain a reddish gray powder. After heating from
room temperature to 350.degree. C. under air over 1 hour, the
powder was calcined at the same temperature for 3 hours. After the
completion of the calcination, 500 ml of pure water was added and
the mixture was stirred and, furthermore, the powder was separated
by filtration. This operation was repeated five times and, after
adding dropwise an aqueous silver nitrate solution to the wash, it
was confirmed that potassium chloride is not remained. Then, 13.9 g
of a bluish gray powder was obtained by drying this powder at
60.degree. C. for 4 hours. The resulting powder was molded to
adjust the particle size to 8.6-16.0 mesh, thereby obtaining a
ruthenium oxide catalyst supported on titanium oxide.
[0486] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=1.9% by weight
[0487] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=1.5% by weight
[0488] Under the same conditions as those of Example 5 except that
the amount of the sample was 1.31 g and the amount of toluene was
40 ml, the content of the OH group of the carrier was measured. As
a result, 48 ml of a methane gas was evolved. The content of the OH
group of the carrier was 5.6.times.10.sup.-4 (mol/g-carrier).
[0489] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.5 g of
the ruthenium oxide catalyst supported on titanium oxide thus
obtained with 10 g of a commercially available spherical (2 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the oxygen gas (192 ml/min.) was passed through the reaction
tube, the reaction was conducted. 2.0 Hours after the beginning of
the reaction, the formation activity of chlorine per unit weight of
the catalyst was 4.27.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 11
[0490] A catalyst was prepared by the following process. That is, a
titanium oxide powder (STR-60N, 100% rutile crystal system,
manufactured by Sakai Chemical Industry Co., Ltd.) was previously
heated from room temperature to 700.degree. C. under air over 1.9
hours and calcined at the same temperature for 3 hours. Then, 15.0
g of the calcined one was dipped in an aqueous solution of 0.61 g
of commercially available ruthenium chloride (RuCl.sub.3.nH.sub.2O,
Ru content: 37.3% by weight) and 26.7 g of pure water, evaporated
under reduced pressure at 50.degree. C. for 4 hours, and then dried
at 60.degree. C. for 2 hours. After drying, the powder was
sufficiently ground to obtain a dark green powder. This powder was
dipped in a solution of 3.2 g of a 2N potassium hydroxide solution,
52.6 g of pure water and 0.77 g of hydrazine monohydrate at room
temperature under nitrogen. Bubbling occurred on dipping. After 1
hour, the reduced powder was separated by filtration. To the
resulting powder, 500 ml of pure water was added, followed by
washing for 30 minutes and further separation by filtration. This
operation was repeated seven times. The pH of the wash was 9.9 at
the first time, and the pH of the wash was 7.5 at the seventh time.
To the powder separated by filtration, 50 g of a 2 mol/l of
potassium chloride solution was added and, after stirring, the
powder was separated by filtration again. This operation was
repeated three times. The resulting solid was dried at 60.degree.
C. for 4 hours to obtain a gray powder. After heating from room
temperature to 350.degree. C. under air over 1 hour, the powder was
calcined at the same temperature for 3 hours. After the completion
of the calcination, 500 ml of pure water was added and the mixture
was stirred and, furthermore, the powder was separated by
filtration. This operation was repeated five times and, after
adding dropwise an aqueous silver nitrate solution to the wash, it
was confirmed that potassium chloride is not remained. Then, 13.5 g
of a bluish gray powder was obtained by drying this powder at
60.degree. C. for 4 hours. The resulting powder was molded to
adjust the particle size to 8.6-16.0 mesh, thereby obtaining a
ruthenium oxide catalyst supported on titanium oxide.
[0491] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=2.0% by weight
[0492] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=1.5% by weight
[0493] Under the same conditions as those of Example 5 except that
the amount of the sample was 2.02 g and the amount of toluene was
40 ml, the content of the OH group of the carrier was measured. As
a result, 46 ml of a methane gas was evolved. The content of the OH
group of the carrier was 3.3.times.10.sup.-4 (mol/g-carrier).
[0494] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.5 g of
the ruthenium oxide catalyst supported on titanium oxide thus
obtained with 10 g of a commercially available spherical (2 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the oxygen gas (192 ml/min.) was passed through the reaction
tube, the reaction was conducted. 2.0 Hours after the beginning of
the reaction, the formation activity of chlorine per unit weight of
the catalyst was 4.32.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 12
[0495] A catalyst was prepared by the following process. That is,
120 of a titanium oxide powder (STR-60N, rutile crystal,
manufactured by Sakai Chemical Industry Co., Ltd.) was kneaded with
76.3 g of pure water and 15.8 g of a titanium oxide sol (CSB,
TiO.sub.2 content: 38% by weight, manufactured by Sakai Chemical
Industry Co., Ltd.). At room temperature, a dry air was blown to
the kneaded one, which was then dried until suitable viscosity was
obtained. The weight loss of water by drying was 10.5 g. After
drying, the mixture was sufficiently kneaded again. This kneaded
one was extruded into a form of a noodle of 1.5 mm .phi. in size.
After drying under air at 60.degree. C. for 4 hours, 119 g of a
white noodle-shaped titanium oxide was obtained. After heating
under air from room temperature to 500.degree. C. over 1.4 hours,
calcination was conducted at the same temperature for 3 hours.
After the completion of the calcination, 115 g of a white extruded
titanium oxide was obtained by cutting the noodle-shaped solid into
pieces of about 5 mm in size. Then, 50.0 g of the resulting carrier
was impregnated with an aqueous solution prepared by dissolving
2.04 g of commercially available ruthenium chloride
(RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by weight) in 27.0 g of
pure water, and dried at 60.degree. C. for 2 hours. Then, the
resulting solid was dipped in a solution of 10.5 g of a 2N
potassium hydroxide solution, 300 g of pure water and 2.57 g of
hydrazine monohydrate under nitrogen at room temperature, followed
by dipping for 1 hour with stirring every 15 minutes after the
reduction, filtration was conducted by using a glass filter.
Bubbling occurred on dipping. 500 ml of pure water was added,
followed by washing for 30 minutes and further separation by
filtration. This operation was repeated five times. The pH of the
wash was 8.8 at the first time, and the pH of the wash was 6.8 at
the fifth time. To the resulting extruded solid separated by
filtration, 100 g of a 0.5 mol/l of potassium chloride solution was
added and, after stirring and allowing to stand 30 minutes, the
resulting extruded solid was separated by filtration again. This
operation was repeated three times. The resulting extruded solid
was dried at 60.degree. C. for 4 hours to obtain a gray solid.
After heating from room temperature to 350.degree. C. under air
over 1 hour, the solid was calcined at the same temperature for 3
hours. After the completion of the calcination, 500 ml of pure
water was added and the mixture was stirred and, furthermore, the
solid was separated by filtration. This operation was repeated five
times over 5 hours and, after adding dropwise an aqueous silver
nitrate solution to the wash, it was confirmed that potassium
chloride is not remained. Then, 50.7 g of a bluish gray extruded
ruthenium oxide catalyst supported on titanium oxide was obtained
by drying this resultant extruded solid at 60.degree. C. for 4
hours. Furthermore, the same operation from the impregnation step
was repeated to obtain 50.8 g of a bluish gray extruded ruthenium
oxide catalyst supported on titanium oxide. These catalysts were
mixed to obtain 101.5 g of a bluish gray extruded ruthenium oxide
catalyst supported on titanium oxide.
[0496] Incidentally, the calculated value of the content of
ruthenium oxide as the active component (A) of the catalyst was as
follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2
(rutilcrystal)+TiO.sub.2(binder)).times.100- =2.0% by weight
[0497] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2(rutil
crystal)+TiO.sub.2(binder)).times.100=1.5% by weight
[0498] Rutil titanium oxide shows that thermal conductivity of
solid phase is 7.5 W/m. .degree. C. measured at 200.degree. C. The
calculated value of the content of rutil titanium oxide as
component (B) was as follows.
TiO.sub.2(rutil crystal)/(RuO.sub.2+TiO.sub.2(rutil
crystal)+TiO.sub.2(binder)).times.100=93.4% by weight
[0499] X-ray diffraction analysis of the titanium oxide catalyst
used was conducted under the same conditions as those of Example 1.
As a result, the content of the rutile crystal was 97%.
[0500] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.50 g of
the ruthenium oxide catalyst supported on titanium oxide thus
obtained with 10 g of a commercially available spherical (2 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the oxygen gas (206 ml/min.) was passed through the reaction
tube, the reaction was conducted. 2.0 Hours after the beginning of
the reaction, the formation activity of chlorine per unit weight of
the catalyst was 4.83.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 13
[0501] A catalyst was prepared by the following process. That is,
10.0 g of a titanium oxide powder (MT-600B, rutile crystal system,
manufactured by TAYCA Corporation ) was impregnated with an aqueous
solution of 0.407 g of commercially available ruthenium chloride
(RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by weight) and 17.8 g of
pure water, and then evaporated under reduced pressure at
40.degree. C. over 2 hours. After drying at 60.degree. C. for 2
hours, the powder was sufficiently ground to obtain a dark green
powder. This powder was dipped in a solution of 2.1 g of a 2N
potassium hydroxide solution and 30.0 of pure water at room
temperature, followed by stirring. After 1 minute, under nitrogen,
a solution of 0.59 g of hydrazine monohydrate and 5.0 g of pure
water was added to the suspension under stirring at room
temperature under nitrogen. Bubbling occurred on dipping. After 1
hour, the reduced powder was separated by filtration. To the
resulting powder, 500 ml of pure water was added, followed by
washing for 30 minutes and further separation by filtration. This
operation was repeated five times. The pH of the wash was 8.8 at
the first time, and the pH of the wash was 7.4 at the fifth time.
To the powder separated by filtration, 50 g of a 2 mol/l of
potassium chloride solution was added and, after stirring, the
powder was separated by filtration again. This operation was
repeated three times. The resulting solid was dried at 60.degree.
C. for 4 hours to obtain a beige powder. After heating from room
temperature to 350.degree. C. under air over 1 hour, the powder was
calcined at the same temperature for 3 hours. After the completion
of the calcination, 500 ml of pure water was added and the mixture
was stirred and, furthermore, the powder was separated by
filtration. This operation was repeated five times and, after
adding dropwise an aqueous silver nitrate solution to the wash, it
was confirmed that potassium chloride is not remained. Then, 9.23 g
of a bluish gray powder was obtained by drying this powder at
60.degree. C. for 4 hours. The resulting powder was molded to
adjust the particle size to 8.6-16.0 mesh, thereby obtaining a
ruthenium oxide catalyst supported on titanium oxide.
[0502] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=2.0% by weight
[0503] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=1.5% by weight
[0504] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.5 g of
the ruthenium oxide catalyst supported on titanium oxide thus
obtained with 5 g of a commercially available spherical (1 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the hydrogen chloride gas (211 ml/min.) and the oxygen gas
(211 ml/min.) were passed through the reaction tube, the reaction
was conducted. 1.8 Hours after the beginning of the reaction, the
formation activity of chlorine per unit weight of the catalyst was
4.40.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 14
[0505] A catalyst was prepared by the following process. That is,
270 g of pure water and 134 g of a 30 wt % titanium sulfate
solution (manufactured by Wako Pure Chemical Industry, Ltd.) were
mixed at room temperature. The resulting solution was mixed with
10.0 g of a titanium oxide powder (PT-101, 100% rutile crystal,
manufactured by Ishihara Techno Corporation ) at room temperature.
Then, the resulting suspension was hydrolyzed by heating to
102.degree. C. under stirring over 7 hours using an oil bath. After
the completion of the hydrolysis, the reaction solution was cooled
to room temperature, allowed to stand overnight, and then separated
by filtration. 0.5 liter of pure water was added to the resulting
white precipitate and, after washing for 30 minutes, the
precipitate was separated by filtration. This operation was
repeated eight times. Then, the resulting precipitate was dried at
60.degree. C. for 4 hours to obtain 25.0 g of a white powder. This
powder was heated to 300.degree. C. in an air over 1 hour and then
calcined at the same temperature for 5 hours to obtain 23.2 g of a
white solid. Furthermore, 20.2 g of this powder was taken out,
heated to 500.degree. C. under air over 1.4 hour and then calcined
at the same temperature for 3 hours to obtain 19.5 g of a white
solid. The resulting solid was ground to obtain a titanium oxide
powder.
[0506] The resulting titanium oxide powder (9.5 g) was impregnated
with an aqueous solution prepared previously by dissolving 1.27 g
of commercially available ruthenium chloride (RuCl.sub.3.nH.sub.2O,
Ru content: 37.3% by weight) and 9.5 g of pure water, and then
evaporated under reduced pressure at 40.degree. C. over 2 hours.
After drying at 60.degree. C. for 2 hours, the powder was
sufficiently ground to obtain a black powder. This powder was
dipped in a solution of 6.6 g of a 2N potassium hydroxide solution
and 28.5 g of pure water at room temperature, followed by stirring.
After 1 minute, a solution of 1.83 g of hydrazine monohydrate and
4.8 g of pure water was added to the suspension under stirring at
room temperature under nitrogen. Bubbling occurred on dipping.
After 1 hour, the reduced powder was separated by filtration. To
the resulting powder, 500 ml of pure water was added, followed by
washing for 30 minutes and further separation by filtration. This
operation was repeated five times. The pH of the wash was 8.2 at
the first time, and the pH of the wash was 6.6 at the fifth time.
To the powder separated by filtration, 48 g of a 2 mol/l of
potassium chloride solution was added and, after stirring, the
powder was separated by filtration again. This operation was
repeated three times. The resulting solid was dried at 60.degree.
C. for 4 hours to obtain 10.2 g of a black powder. After heating
from room temperature to 350.degree. C. in an air over 1 hour, the
powder was calcined at the same temperature for 3 hours. After the
completion of the calcination, 500 ml of pure water was added and
the mixture was stirred and, furthermore, the powder was separated
by filtration. This operation was repeated five times and, after
adding dropwise an aqueous silver nitrate solution to the wash, it
was confirmed that potassium chloride is not remained. Then, 8.93 g
of a black powder was obtained by drying this powder at 60.degree.
C. for 4 hours. The resulting powder was molded to adjust the
particle size to 8.6-16.0 mesh, thereby obtaining a ruthenium oxide
catalyst supported on titanium oxide.
[0507] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.2% by weight
[0508] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0509] X-ray diffraction analysis of the titanium oxide catalyst
used was conducted under the same conditions as those of Example 1.
As a result, a peak intensity of a rutile crystal
(2.theta.=27.4.degree.) was1497 cps. On the contrary a peak
intensity of an anatase crystal(2.theta.=25.3 ) was not detected.
Consequently, the content of the rutile crystal was 100%.
[0510] Under the same conditions as those of Example 5 except that
the amount of the sample was 2.36 g and the amount of toluene was
40 ml, the content of the OH group of the carrier was measured. As
a result, 51 ml of a methane gas was evolved. The content of the OH
group of the carrier was 3.7.times.10.sup.-4 (mol/g-carrier).
[0511] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.5 g of
the ruthenium oxide catalyst supported on titanium oxide thus
obtained with 10 g of a commercially available spherical (2 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the hydrogen chloride gas (211 ml/min.) and the oxygen gas
(211 ml/min.) were passed through the reaction tube, the reaction
was conducted. 2.3 Hours after the beginning of the reaction, the
formation activity of chlorine per unit weight of the catalyst was
8.18.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 15
[0512] A catalyst was prepared by the following process. That is, a
titanium oxide powder (100% rutile crystal manufactured by Sakai
Chemical Industry Co., Ltd.) was previously heated from room
temperature to 500.degree. C. under air over 1.4 hours and calcined
at the same temperature for 3 hours. Then, 10.0 g of the calcined
one was dipped in an aqueous solution of 1.34 g of commercially
available ruthenium chloride (RuCl.sub.3.nH.sub.2O, Ru content:
37.3% by weight) and 17.8 g of pure water, evaporated under reduced
pressure at 40.degree. C. over 2 hours, and then dried at
60.degree. C. for 2 hours. After drying, the powder was
sufficiently ground to obtain a blackish brown powder. This powder
was dipped in a solution of 6.9 g of a 2N potassium hydroxide
solution, 30.0 g of pure water and 1.93 g of hydrazine monohydrate
under nitrogen at room temperature. Bubbling occurred on dipping.
After 1 hour, the reduced powder was separated by filtration. To
the resulting powder, 500 ml of pure water was added, followed by
washing for 30 minutes and further separation by filtration. This
operation was repeated five times. The pH of the wash was 8.7 at
the first time, and the pH of the wash was 7.4 at the fifth time.
To the powder separated by filtration, 50 g of a 2 mol/l of
potassium chloride solution was added and, after stirring, the
powder was separated by filtration again. This operation was
repeated three times. The resulting solid was dried at 60.degree.
C. for 4 hours to obtain a black powder. After heating from room
temperature to 350.degree. C. under air over 1 hour, the powder was
calcined at the same temperature for 3 hours. After the completion
of the calcination, 500 ml of pure water was added and the mixture
was stirred and, furthermore, the powder was separated by
filtration. This operation was repeated five times and, after
adding dropwise an aqueous silver nitrate solution to the wash, it
was confirmed that potassium chloride is not remained. Then, 9.7 g
of a black powder was obtained by drying this powder at 60.degree.
C. for 4 hours. The resulting powder was molded to adjust the
particle size to 8.6-16.0 mesh, thereby obtaining a ruthenium oxide
catalyst supported on titanium oxide.
[0513] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.2% by weight
[0514] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0515] X-ray diffraction analysis of the titanium oxide catalyst
used was conducted under the same conditions as those of Example 1.
As a result, a peak intensity of a rutile crystal
(2.theta.=27.4.degree.) was 907 cps. On the contrary, a peak
intensity of an anatase crystal (2.theta.=25.3.degree.) was not
detected. Consequently, the content of the rutile crystal was
100%.
[0516] Under the same conditions as those of Example 5 except that
the amount of the sample was 1.64 g and the amount of toluene was
40 ml, the content of the OH group of the carrier was measured. As
a result, 54 ml of a methane gas was evolved. The content of the OH
group of the carrier was 6.0.times.10.sup.-4 (mol/g-carrier).
[0517] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.5 g of
the ruthenium oxide catalyst supported on titanium oxide thus
obtained with 10 g of a commercially available spherical (2 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the hydrogen chloride gas (211 ml/min.) and the oxygen gas
(211 ml/min.) were passed through the reaction tube, the reaction
was conducted. 1.8 Hours after the beginning of the reaction, the
formation activity of chlorine per unit weight of the catalyst was
7.85.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 16
[0518] A catalyst was prepared by the following process. That is,
10.1 g of a titanium oxide powder (SSP-HJ, anatase crystal,
manufactured by Sakai Chemical Industry Co., Ltd.) was impregnated
with an aqueous solution prepared previously by dissolving 1.35 g
of commercially available ruthenium chloride (RuCl.sub.3.nH.sub.2O,
Ru content: 37.3% by weight) in 4.5 g of pure water, and then dried
at 60.degree. C. for 2 hours. After drying, the powder was
sufficiently ground in a mortar to obtain a black powder. To reduce
this powder with sodium boron hydride, a solution was prepared by
dissolving 1.65 g of sodium boron hydride in 330 g of ethanol and
cooled in an ice bath. To this sodium boron hydride solution, the
total amount of ruthenium chloride supported on titanium oxide was
added with stirring. Bubbling occurred on addition. After 1 hour,
the supernatant was removed by decantation. 500 ml of pure water
was added, followed by washing for 30 minutes and further
separation by filtration. This operation was repeated five times.
The pH of the wash at the first time was 9.3, and the pH of the
wash at the fifth time was 5.3. The resulting cake was dried at
60.degree. C. for 4 hours. As a result, 9.8 g of a black powder was
obtained. Then, the resulting powder was impregnated with an
aqueous solution of 1.21 g of potassium chloride and 4.2 g of pure
water. The resulting powder was dried at 60.degree. C. for 4 hours.
After heating from room temperature to 350.degree. C. under air
over 1 hour, the powder was calcined at the same temperature for 3
hours. After the completion of the calcination, 500 ml of pure
water was added and the mixture was stirred and, furthermore, the
powder was separated by filtration. This operation was repeated
five times and, after adding dropwise an aqueous silver nitrate
solution to the wash, it was confirmed that potassium chloride is
not remained. Then, 9.3 g of a black powder was obtained by drying
this powder at 60.degree. C. for 4 hours. The resulting powder was
molded to adjust the particle size to 8.6-16.0 mesh, thereby
obtaining a ruthenium oxide catalyst supported on titanium
oxide.
[0519] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.1% by weight
[0520] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0521] Under the same conditions as those of Example 5 except that
the amount of the sample was 1.79 g and the amount of toluene was
40 ml, the content of the OH group of the carrier was measured. As
a result, 111 ml of a methane gas was evolved. The content of the
OH group of the carrier was 18.6.times.10.sup.-4
(mol/g-carrier).
[0522] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube in the same manner as that in Example 2 and that the hydrogen
chloride (187 ml/min.) and the oxygen gas (199 ml/min.) were passed
through the reaction tube, the reaction was conducted. 2.0 Hours
after the beginning of the reaction, the formation activity of
chlorine per unit weight of the catalyst was 3.59.times.10.sup.-4
mol/min.g-catalyst.
EXAMPLE 17
[0523] A catalyst was prepared by the following process. That is,
10.0 g of a titanium oxide powder (P25, manufactured by Nippon
AEROSIL Co., Ltd.) was impregnated with an aqueous solution
prepared previously by dissolving 1.34 g of commercially available
ruthenium chloride (RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by
weight) in 4.8 g of pure water, and then dried at 60.degree. C. for
2 hours. After drying, the powder was sufficiently ground in a
mortar to obtain a black powder. To reduce this powder with sodium
boron hydride, a solution was prepared by dissolving 1.66 g of
sodium boron hydride in 330 g of ethanol and cooled in an ice bath.
To this sodium boron hydride solution, the total amount of
ruthenium chloride supported on titanium oxide was added with
stirring. Bubbling occurred on addition. After 1 hour, the
supernatant was removed by decantation. 500 ml of pure water was
added, followed by washing for 30 minutes and further separation by
filtration. This operation was repeated nine times. The pH of the
wash at the first time was 9.6, and the pH of the wash at the ninth
time was 7.7. The resulting cake was dried at 60.degree. C. for 4
hours. As a result, a black powder was obtained. Then, the
resulting powder was impregnated with an aqueous solution of 1.22 g
of potassium chloride and 4.7 g of pure water. The impregnated
powder was dried at 60.degree. C. for 4 hours. After heating from
room temperature to 350.degree. C. under air over 1 hour, the
powder was calcined at the same temperature for 3 hours. After the
completion of the calcination, 500 ml of pure water was added and
the mixture was stirred and, furthermore, the powder was separated
by filtration. This operation was repeated five times and, after
adding dropwise an aqueous silver nitrate solution to the wash, it
was confirmed that potassium chloride is not remained. Then, 9.5 g
of a black powder was obtained by drying this powder at 60.degree.
C. for 4 hours. The resulting powder was molded to adjust the
particle size to 8.6-16.0 mesh, thereby obtaining a ruthenium oxide
catalyst supported on titanium oxide.
[0524] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.2% by weight
[0525] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0526] X-ray diffraction analysis of the titanium oxide powder used
was conducted. As a result, the content of the rutile crystal was
17%.
[0527] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube in the same manner as that in Example 2 and that the hydrogen
chloride (195 ml/min.) and the oxygen gas (198 ml/min.) were passed
through the reaction tube and the internal temperature was adjusted
to 299.degree. C., the reaction was conducted. 2.0 Hours after the
beginning of the reaction, the formation activity of chlorine per
unit weight of the catalyst was 4.31.times.10.sup.-4
mol/min.g-catalyst.
EXAMPLE 18
[0528] A catalyst was prepared by the following process. That is,
60 g of a commercially available 100% rutile type titanium oxide
powder (STR-60N, manufactured by Sakai Chemical Industry Co., Ltd.)
and 60 g of a .alpha.-alumina powder (Al31-03, manufactured by
Sumitomo Chemical Co., Ltd.) were sufficiently mixed. To the mixed
one, a mixed solution of 15.8 g of 38 wt % TiO.sub.2 sol (CSB,
manufactured by Sakai Chemical Industry Co., Ltd.) and 50 g of pure
water was added. Until suitable viscosity was obtained, the mixture
was dried at room temperature under air flow. After drying, the
mixture was sufficiently kneaded. The weight loss by drying was 14
g. This kneaded one was extruded into a form of a noodle of 1.5 mm
.phi. in size, followed by drying at 60.degree. C. under air for 4
hours using a drier. The weight of the dried one was 101 g. Using a
muffle furnace, the dried one was heated from room temperature to
500.degree. C. in an air over 1.4 hours and calcined at the same
temperature for 3 hours to obtain 99.5 g of a titanium
oxide-.alpha.-alumina carrier.
[0529] The same operation was repeated to obtain 218 g of a
titanium oxide-.alpha.-alumina carrier.
[0530] Then, a extruded titanium oxide-.alpha.-alumina carrier was
obtained by cutting the resulting noodle-shaped titanium oxide-
.alpha.-alumina carrier into pieces of about 5 mm in size.
[0531] Then, 2.03 g of commercially available ruthenium chloride
(RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by weight) was dissolved
in 14.6 g of water, followed by sufficient stirring to obtain an
aqueous ruthenium chloride solution. The resulting aqueous
ruthenium chloride solution was added dropwise to 50 g of the
extruded titanium oxide-.alpha.-alumina carrier, thereby to support
ruthenium chloride by impregnation. The supported one was dried
under air at 60.degree. C. for 2 hours to obtain a ruthenium
chloride supported on titanium oxide-.alpha.-alumina.
[0532] The resulting ruthenium chloride supported on titanium
oxide-.alpha.-alumina was added to a mixed solution of 10.5 g of an
aqueous potassium hydroxide solution adjusted to 2 mol/l, 300 g of
pure water and 2.54 g of hydrazine monohydrate under nitrogen at
room temperature, followed by dipping for 1 hour stirring every 15
minutes. At the time of dipping, bubbling was observed in the
solution. After the reduction, filtration was conducted by using a
glass filter. 0.5 liter of pure water was added to the glass filter
and, after allowing to stand for 30 minutes, filtration was
conducted again. This operation was repeated five times to obtain a
brownish white extruded solid. Then, 100 g of an aqueous KCl
solution adjusted to 0.5 mol/l was added to the resulting extruded
solid and, after allowing to stand for 30 minutes, filtration was
conducted under reduced pressure. The same operation was repeated
three times.
[0533] The resulting extruded solid was dried under air at
60.degree. C. for 4 hours, heated to 350.degree. C. under air over
1 hour, and then calcined at the same temperature for 3 hours.
[0534] 0.5 liter of pure water was added to the calcined one and
the mixture was stirred. After allowing to stand for 30 minutes,
further more filtration was conducted by using a glass filter. This
operation was repeated five times over 5 hours to remove potassium
chloride until white turbidity does not occur when 0.2 mol/l of an
aqueous silver nitrate solution is added to the filtrate. Then, the
resultant was dried in an air at 60.degree. C. for 4 hours to
obtain 50 g of a bluish gray ruthenium oxide catalyst supported on
titanium oxide-.alpha.-alumina.
[0535] The same operation was repeated four time to obtain 200 g of
a ruthenium oxide catalyst supported on titanium
oxide-.alpha.-alumina.
[0536] According to the same reaction manner as that described in
Example 2 except that 2.50 g of the ruthenium oxide catalyst
supported on titanium oxide-.alpha.-alumina thus obtained was
diluted with 10 g of a commercially available spherical (2 mm in
size) alumina carrier (SSA995, manufactured by Nikkato Co.) and
then charged in a quartz reaction tube (inner diameter: 12 mm) and
that the oxygen gas (192 ml/min.) was passed through the reaction
tube, the reaction was conducted. 2.0 Hours after the beginning of
the reaction, the formation activity of chlorine per unit weight of
the catalyst was 4.62.times.10.sup.-4 mol/min.g-catalyst.
[0537] Then, the controllability of the reaction temperature of the
ruthenium oxide catalyst supported on titanium oxide.alpha.-alumina
was evaluated.
[0538] That is, 40.6 g of the resulting ruthenium oxide catalyst
supported on titanium oxide-.alpha.-alumina was charged in a nickel
reaction tube (outer diameter: 29 mm .phi., inner diameter: 25
mm.phi., outer diameter of sheath tube for thermocouple: 6 mm
.phi.). The length of the catalyst bed was 9.2 cm and the volume of
catalyst was 42.5 ml.
[0539] Incidentally, the calculated value of the content of
ruthenium oxide as the active component (A) of the catalyst was as
follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2(rutile crystal
)+.alpha.-Al.sub.2O.sub.3+Ti- O.sub.2(binder)).times.100=2.0% by
weight
[0540] Rutil titanium oxide shows that thermal conductivity of
solid phase is 7.5 W/m. .degree. C. measured at 200.degree. C. The
calculated value of the content of rutile titanium oxide as the
component (B) was as follows.
TiO.sub.2(rutile crystal )/(RuO.sub.2+TiO.sub.2(rutile crystal
)+.alpha.-Al.sub.2O.sub.3+TiO.sub.2(binder)).times.100=47% by
weight
[0541] .alpha.-Al.sub.2O.sub.3 shows that thermal conductivity of
solid phase is 23 W/m. .degree. C. measured at 200.degree. C. The
calculated value of the content of .alpha.-alumina as the component
(B) was as follows.
.alpha.Al.sub.2O.sub.3/(RuO.sub.2+TiO.sub.2(rutile crystal
)+.alpha.-Al.sub.2O.sub.3+TiO.sub.2(binder)).times.100=47% by
weight
[0542] The calculated value of TiO.sub.2(binder) used to form this
catalyst was 4.7% by weight.
[0543] Then, the nickel reaction tube was heated in a salt bath of
sodium nitrite and potassium nitrate and the hydrogen chloride gas
(0.88 Nl/min.) and the oxygen gas (0.53 Nl/min.) were supplied. 3.7
Hours after the beginning of the reaction, when the temperature of
the salt bath is 260.degree. C., the maximum temperature of the
catalyst bed is exhibited at the point which is 3 cm from the
catalyst bed inlet and the internal temperature (hot spot) became
stable at 301.degree. C. The gas at the reaction outlet was sampled
by passing it through an aqueous 30% potassium iodide solution, and
then the amount of chlorine formed and amount of the non-reacted
hydrogen chloride were respectively determined by iodometric
titration and neutralization titration. As a result, the conversion
of hydrogen chloride was 50.4%.
[0544] Furthermore, the bath temperature was raised by 11.degree.
C. in total over 5 hours and 50 minutes to make it constant at
271.degree. C. As a result, the internal temperature became stable
at 331.4.degree. C. Even after 10 minutes, the bath temperature was
constant at 271.degree. C. and the internal temperature was stable
at 331.5C, and the temperature was satisfactorily controlled.
[0545] Furthermore, the bath temperature was raised by 8.degree. C.
in total over 1 hour and 15 minutes to make it constant at 279C. As
a result, the internal temperature became stable at 351.9.degree.
C. Even after 10 minutes, the bath temperature was constant at 279
C and the internal temperature was stable at 351.9.degree. C., and
the temperature was satisfactorily controlled.
EXAMPLE 19
[0546] A catalyst was prepared by the following process. That is,
0.81 g of commercially available ruthenium chloride hydrate
(RuCl.sub.3.nH2O Ru content: 37.3% by weight) was dissolved in 6.4
g of water, followed by sufficient stirring to obtain an aqueous
ruthenium chloride solution. The resulting aqueous solution was
added dropwise to 20 g of a titanium oxide carrier powder (P-25,
manufactured by Nippon AEROSIL Co., Ltd.), thereby to support
ruthenium chloride by impregnation. The supported ruthenium
chloride on titanium oxide powder was ground, and then sufficiently
mixed until the whole color became homogeneous yellowish green.
20.2 g of a supported ruthenium chloride on titanium oxide was
obtained by dying the supported one under air at 60.degree. C. for
2 hours. The same operation was repeated twice to obtain 40.4 g of
the same supported one.
[0547] Then, 40.4 g of the resulting supported ruthenium chloride
on titanium oxide was added to a mixed solution of 8.36 g of an
aqueous potassium hydroxide solution adjusted to 2 mol/l, 140 g of
pure water and 2.14 g of a hydrazine monohydrate with stirring
under nitrogen at room temperature, followed by stirring at room
temperature for 60 minutes. Then, the mixed solution was filtered
by using a glass filter to obtain a beige cake. 0.5 liter of pure
water was added to the resulting cake and filtration was conducted
again by using a glass filter. This operation was repeated five
times to obtain a brownish white cake.
[0548] Then, 200 g of an aqueous KCl solution adjusted to 0.25
mol/l was added to the resulting cake and, after allowing to stand
for 30 minutes, filtration was conducted under reduced pressure.
The same operation was repeated three times to obtain a brownish
white cake. The resulting cake was dried under air at 60.degree. C.
for 4 hours, and ground by using a mortar to obtain 39.4 g of
greenish gray powder. Then, 8 g of the resulting greenish gray
powder and 8 g of .alpha.-alumina powder (AES-12, manufactured by
Sumitomo Chemical Co., Ltd.) were sufficiently mixed. To the mixed
one, a mixed solution of 2.1 g of 38 wt % TiO.sub.2 sol (CSB,
manufactured by Sakai Chemical Industry Co., Ltd.) and 4.0 g of
pure water was added and mixed sufficiently. Until suitable
viscosity is obtained, pure water was added, followed by kneading.
The amount of pure water added is 0.45 g. The kneaded one was
extruded into a form of a noodle of 1.5 mm .phi. in size, followed
by drying at 60.degree. C. under air for 4hours using a drier. The
weight of the dried one was 5.93 g. Using a muffle furnace, the
dried one was heated from room temperature to 350.degree. C. under
air over 1 hour and calcined at the same temperature for 3 hours.
Then, 0.5 liter of pure water was added to the calcined one and
filtration was conducted by using a glass filter. This operation
was repeated five times to obtain a bluish gray solid. The
resulting solid was dried under air at 60.degree. C. for 4 hours
using a drier to obtain 5.86 g of a catalyst. Then, a bluish gray
extruded ruthenium oxide catalyst supported on titanium oxide mixed
with .alpha.-alumina was obtained by cutting the resulting solid
into pieces of about 5 mm in size.
[0549] Incidentally, the calculated value of the content of
ruthenium oxide as the active component (A) of the catalyst was as
follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2(catalyst carrier component
)+.alpha.-Al.sub.2O.sub.3+TiO.sub.2(binder)).times.100=1.0% by
weight
[0550] .alpha.-Al.sub.2O.sub.3 shows that thermal conductivity of
solid phase is 23 W/m. .degree. C. measured at 200.degree. C. The
calculated value of the content of .alpha.-alumina as the component
(B) was as follows.
.alpha.-Al.sub.2O.sub.3 (component (B)
)/(RuO.sub.2+TiO.sub.2(catalyst carrier
component)+.alpha.-Al.sub.2O.sub.3+TiO.sub.2(binder)).times.100=4-
7.1% by weight
[0551] The calculated value of the content of TiO.sub.2(binder)
used to form this catalyst was 4.8% by weight.
[0552] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by mixing 2.50 g of
the ruthenium oxide catalyst supported on titanium oxide mixed with
.alpha.-alumina thus obtained with 5 g of a commercially available
spherical (1 mm in size) .alpha.-alumina carrier (SSA995,
manufactured by Nikkato Co.) and then charged in a quartz reaction
tube (inner diameter: 12 mm) and that the oxygen gas (211 ml/min.)
and hydrogen chloride gas (211 ml/min.) was passed through the
reaction tube, the reaction was conducted. 1.8 Hours after the
beginning of the reaction, the formation activity of chlorine per
unit weight of the catalyst was 3.05.times.10.sup.-4 mol/min.g-
catalyst.
[0553] Then, the controllability of the ruthenium oxide catalyst
supported on titanium oxide mixed with .alpha.-alumina was
evaluated.
[0554] That is, 5 g of the catalyst thus obtained was charged in a
quartz reaction tube (outer diameter: 15 mm, inner diameter: 12 mm)
without being diluted with an .alpha.-alumina sphere. The hydrogen
chloride gas (192 ml/min.) and the oxygen gas (192 ml/min.) were
supplied. Then, the quartz reaction tube was heated in a electric
furnace and the internal temperature (hot spot) was adjusted to
300.degree. C. 1.8 Hours after the beginning of the reaction, the
conversion of hydrogen chloride was 21%. Furthermore, the furnace
temperature was slowly raised, step by step, by 1.degree. C. 5.7
Hours after the beginning of the reaction, the internal temperature
became stable at 328.degree. C. Furthermore, the furnace
temperature was raised by 3.degree. C. over 32 minutes. As a
result, the internal temperature became stable at 335.degree. C.,
and the temperature was satisfactorily controlled.
EXAMPLE 20
[0555] A catalyst was prepared by the following process. That is,
6.02 g of a spherical (1-2 mm in size) 5 wt % metal ruthenium
catalyst supported on titanium oxide (manufactured by N.E. Chemcat
Co., Ltd. titanium oxide is anatase crystal ) was impregnated with
an aqueous potassium chloride solution adjusted to 0.5mol/l until
water oozes out on the surface of the catalyst, and then dried
under air at 60.degree. C., for 10 to 60 minutes. This operation
was repeated twice. The amount of the potassium chloride solution
added was 3.04 g at the first time, 2.89 g at the second time
respectively. The total amount was 5. 83 g. The calculated value of
the molar ratio of the amount of potassium chloride added to a Ru
atom in the catalyst becomes 1:1. This solid was dried under air at
60.degree. C. for 4 hours, and heated from room temperature to
350.degree. C. under air over about 1 hour, and then calcined at
the same temperature for 3 hours to obtain a spherical solid. 0.5
liter of pure water was added to the resulting solid and the solid
followed by stirring at room temperature for 1 minutes. Then, the
solid was filtered. This operation was repeated four times until
white turbidity does not occur when 0.2 mol/l of an aqueous silver
nitrate solution is added to the filtrate.
[0556] Then, the resulting solid was dried in an air at 60.degree.
C. for 4 hours to obtain 5.89 g of a bluish black 6.6 wt %
ruthenium oxide catalyst supported on titanium oxide.
[0557] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the spherical 6.6 wt % ruthenium
oxide catalyst supported on titanium oxide obtained was charged in
a quartz reaction tube and that the hydrogen chloride gas (187
ml/min.) and the oxygen gas (199 ml/min.) were passed through the
reaction tube, the reaction was conducted. 2.0 Hours after the
beginning of the reaction, the formation activity of chlorine per
unit weight of the catalyst was 4.07.times.10.sup.-4
mol/min.g-catalyst.
[0558] Then, 10 g of the spherical 6.6 wt % ruthenium oxide
catalyst supported on titanium oxide was prepared by the same
process as described above.
[0559] Then, the mixture catalyst system which comprises the
molding of ruthenium oxide catalyst supported on titanium oxide and
the molding of .alpha.-alumina was evaluated whether the catalyst
system can attain enough reaction conversion by keeping the whole
catalyst bed at sufficient temperature for desirable reaction rate
in the oxidation of hydrogen chloride. That is, 9.84 g (10 ml) of
the molding of the resulting 6.6 wt % ruthenium oxide catalyst
supported on titanium oxide was sufficiently mixed with 65.3 g (30
ml) of .alpha.-alumina (SSA995, sphere of 2 mm in size,
manufactured by Nikkato Co., Ltd.) and was charged in a quartz
reaction tube (outer diameter: 25 mm .phi., outer diameter of
sheath tube for thermocouple : 4 mm .phi.). The length of catalyst
bed was 11 cm.
[0560] Incidentally, the calculated value of the content of
ruthenium oxide as the active component (A) of the catalyst was as
follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2 (catalyst carrier
component)+.alpha.-Al.sub- .2O.sub.3).times.100=0.86% by weight
[0561] .alpha.-Al.sub.2O.sub.3 shows that thermal conductivity of
solid phase is 23 W/m. .degree. C. measured at 200.degree. C. The
calculated value of the content of .alpha.-alumina as the component
(B) of the catalyst system was as follows.
.alpha.Al.sub.2O.sub.3/(RuO.sub.2+TiO.sub.2(catalyst carrier
component )+.alpha.-Al.sub.2O.sub.3) .times.100=86.9% by weight
[0562] Then, the quartz reaction tube was heated in a electric
furnace and the hydrogen chloride gas (593 ml/min.) and the oxygen
gas (300 ml/min.) were supplied. 1 Hour and 15 minutes after the
beginning of the supply of hydrogen chloride and oxygen, when the
temperature of the electric furnace was 306.degree. C., the muximum
temperature (hot spot) of the catalyst bed was exhibited at the
point of 4.5 cm from the catalyst bed inlet and the internal
temperature became stable at 391.degree. C. The temperature
distribution of the catalyst bed was as shown in FIG. 8. The gas at
the reaction outlet was sampled by passing it through an aqueous
30% potassium iodide solution, and then the amount of chlorine
formed and amount of the non-reacted hydrogen chloride were
respectively determined by iodometric titration and neutralization
titration. As a result, the conversion of hydrogen chloride was
74.9% and the formation activity of chlorine per unit weight of the
catalyst was 14.9 mol chlorine/l-catalyst system.h.
EXAMPLE 21
[0563] The controllability of the reaction temperature of the
mixture catalyst system which comprises the molding of ruthenium
oxide catalyst supported on titanium oxide and the molding of
.alpha.-alumina was evaluated. That is, 80.1 g of the resulting 6.6
wt % ruthenium oxide catalyst supported on titanium oxide(anatase
crystal) obtained by the same production process of example 20 was
sufficiently mixed with 88.3 g of .alpha.-alumina (SSA995, sphere
of 2 mm in size, manufactured by Nikkato Co., Ltd.) and was charged
in a nickel reaction tube (inner diameter: 18 mm .phi., outer
diameter of sheath tube for thermocouple e: 5 mm .phi.). The length
of the catalyst system bed was 54 cm.
[0564] Incidentally, the calculated value of the content of
ruthenium oxide as the active component (A) of the catalyst was as
follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2(catalyst carrier component
)+.alpha.-Al.sub.2O.sub.3) .times.100=3.2% by weight
[0565] .alpha.-Al.sub.2O.sub.3 shows that thermal conductivity of
solid phase is 23 W/m. .degree. C. measured at 200.degree. C. The
calculated value of the content of .alpha.-alumina as the component
(B) of the catalyst system was as follows.
.alpha.-Al.sub.2O.sub.3/(RuO.sub.2+TiO.sub.2(catalyst carrier
component )+.alpha.-Al.sub.2O.sub.3) .times.100=52.4% by weight
[0566] Then, the nickel reaction tube was heated in a salt bath of
sodium nitrite and potassium nitrate and the hydrogen chloride gas
(6.1 1/min.) and the oxygen gas (3.05 l/min.) were supplied. 1.6
Hours after the beginning of the reaction, when the temperature of
the salt bath is 280.degree. C., the maximum temperature of the
catalyst bed is exhibited at the point which is 10 cm from the
catalyst bed inlet and the internal temperature (hot spot) became
stable at 291.degree. C. Furthermore, the bath temperature was
raisedby 21.degree. C. over 43 minutes to make it constant at
301.degree. C. As a result, the internal temperature became stable
at 322.degree. C. Furthermore, the bath temperature was raised by
14.degree. C. over 1 hour and 40 minutes to make it constant at
315.degree. C. As a result, the internal temperature became stable
at 355.degree. C. Even after 15 minutes, the bath temperature was
constant at 315.degree. C. and the internal temperature was stable
at 355.degree. C., and the temperature was satisfactorily
controlled.
EXAMPLE 22
[0567] A catalyst was prepared by the following process. That is,
30.0 g of a titanium oxide powder (No. 1, anatase crystal,
manufactured by Catalysts & Chemicals Industries Co., Ltd.) was
kneaded with 9.0 g of a crystalline cellulose (manufactured by
MERCK Co.), 24.4 g of a titanium oxide sol (CSB, TiO.sub.2 content:
38% by weight, manufactured by Sakai Chemical Industry Co., Ltd.)
and 25.4 g of water. The kneaded one was dried at 60.degree. C. and
the resultant was molded into a rod-shaped solid. This rod-shaped
solid was dried at 60.degree. C. for 4 hours to obtain 48.8 g of a
white solid. The resulting solid was heated to 500.degree. C. under
air over 3 hours and calcined at the same temperature for 5 hours
to obtain 37.1 g of a white rod-shaped titanium oxide carrier.
Then, the resulting solid was ground to obtain 27.0 g of a solid
having a particle size of 8.6-16 mesh.
[0568] Then, 15.0 g of the titanium oxide carrier thus obtained was
taken out and impregnated with a solution prepared by dissolving
2.05 g of commercially available ruthenium chloride hydrate
(RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by weight) in 9.0 g of
pure water, and dried at 60.degree. C. for 4 hours, thereby to
support ruthenium chloride. 5.5 g of ruthenium chloride supported
on the titanium oxide was taken out. Then, a solution of 1.11 g of
sodium boron hydride (NaBH.sub.4), 4.0 g of water and 42.1 g of
ethanol was prepared. After the solution was sufficiently cooled in
an ice bath, 5.5 g of the ruthenium chloride supported on titanium
oxide was added and ruthenium chloride was reduced. At this time,
bubbling was observed in the solution. After the bubbling was
terminated, the reduced solid was separated by filtration. After
washing again with 500 ml of pure water for 30 minutes, the solid
was separated by filtration. This operation was repeated five
times. Then, this solid was dried at 60.degree. C. for 4 hours to
obtain 5.0 g of a bluish black solid. Then, this solid was
impregnated with a solution prepared by dissolving 0.60 g of
potassium chloride in 2.9 g of pure water, and dried at 60.degree.
C. for 4 hours. The dried one was heated to 350.degree. C. in an
air over 1 hour and calcined at the same temperature for 3 hours.
Then, the calcined solid was washed with 500 ml of pure water and
then separated by filtration. This operation was repeated five
times. After adding dropwise an aqueous silver nitrate solution to
the filtrate, it was confirmed that potassium chloride is not
remained. After washing, the solid was dried 60.degree. C. for 4
hours to obtain 5.1 g of a bluish black ruthenium oxide catalyst
supported on titanium oxide having a particle size of 8.6-16 mesh.
The pore radius of the resulting catalyst was within a range from
0.04 to 0.4 micrometer. The pore distribution curve of this
catalyst measured by a mercury porosimeter is shown in FIG. 4.
[0569] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.3% by weight
[0570] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.8% by weight
[0571] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube in the same manner as that in Example 2 and that the hydrogen
chloride as (187 ml/min.) and the oxygen gas (199 ml/min.) was
passed through the reaction tube and the internal temperature was
adjusted to 301.degree. C., the reaction was conducted. 2.0 Hours
after the beginning of the reaction, the formation activity of
chlorine per unit weight of the catalyst was 4.87.times.10.sup.-4
mol/min.g-catalyst.
EXAMPLE 23
[0572] A catalyst was prepared by the following process. That is,
26.5 g of a titanium oxide powder (No. 1, manufactured by Catalysts
& Chemicals Industries Co., Ltd.) was kneaded with 8.0 g of a
fibrous cellulose (filter paper 5B, manufactured by Toyo Roshi
Kaisha Ltd. ) dispersed in water, 20.9 g of a titanium oxide sol
(CSB, TiO.sub.2 content: 38% by weight, manufactured by Sakai
Chemical Industry Co., Ltd.) and water. The kneaded one was dried
at 60.degree. C. and the resultant was molded into a rod-shaped
solid. This rod-shaped solid was dried at 60.degree. C. for 4 hours
to obtain 41.1 g of a white solid. The resulting solid was heated
to 500.degree. C. under air over 3 hours and calcined at the same
temperature for 5 hours to obtain 31.5 g of a white rod-shaped
titanium oxide cattier. Then, the resulting solid was ground to
obtain 20.4 g of a solid having a particle size of 8.6-16 mesh.
[0573] Then, 5.0 g of the titanium oxide carrier thus obtained was
taken out and impregnated with a solution prepared by dissolving
0.73 g of commercially available ruthenium chloride hydrate
(RuCl.sub.3.nH.sub.2O, Ru content: 35.5% by weight) in 2.8 g of
pure water, and dried at 60.degree. C. for 2 hours, thereby to
support ruthenium chloride. Then, a solution of 0.52 g of sodium
boron hydride (NaBH.sub.4), 2.0 g of water and 40.0 g of ethanol
was prepared. After the solution was sufficiently cooled in an ice
bath, an already prepared ruthenium chloride supported on titanium
oxide was added and ruthenium chloride was reduced. At this time,
bubbling was observed in the solution. After the bubbling was
terminated, the supernatant was separated by decantation. 200 ml of
water was added to the reduced solid, followed by decantation. This
operation was repeated five times. After adding 200 ml of water,
the pH was 9.4. The pH was then adjusted to 7.1 by pouring 4.0 g of
0.1N HCl into this solution. The supernatant was removed by
decantation. After washing again with 500 ml of pure water for 30
minutes, the solid was separated by filtration. This operation was
repeated five times. The pH of the filtrate at the fifth time was
7.1. Then, this solid was dried at 60.degree. C. for 4 hours to
obtain 5.0 g of a bluish black solid. Then, this solid was
impregnated with a solution prepared by dissolving 0.20 g of
potassium chloride in 2.8 g of pure water, and dried at 60.degree.
C. for 4 hours. The dried one was heated to 350.degree. C. under
air over 1 hour and calcined at the same temperature for 3 hours.
Then, the calcined solid was washed with 500 ml of pure water and
then separated by filtration. This operation was repeated five
times. After adding dropwise an aqueous silver nitrate solution to
the filtrate, it was confirmed that potassium chloride is not
remained. After washing, the solid was dried 60.degree. C. for 4
hours to obtain 4.9 g of a bluish black ruthenium oxide catalyst
supported on titanium oxide having a particle size of 8.6-16 mesh.
The pore radius of the resulting catalyst was within a range from
0.04 to 5 micrometer. The pore distribution curve of this catalyst
measured by a mercury porosimeter is shown in FIG. 5.
[0574] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.3% by weight The
calculated value of the content of ruthenium was as follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.8% by weight
[0575] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube in the same manner as that in Example 2 and that the hydrogen
chloride as (187 ml/min.) and the oxygen gas (199 ml/min.) was
passed through the reaction tube, the reaction was conducted. 2.0
Hours after the beginning of the reaction, the formation activity
of chlorine per unit weight of the catalyst was
4.62.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 24
[0576] A catalyst was prepared by the following process. That is,
40.3 g of a titanium oxide powder (No. 1, manufactured by Catalysts
& Chemicals Industries Co., Ltd.) was kneaded with 12.8 g of a
fibrous cellulose (filter paper 5B, manufactured by Toyo Roshi
Kaisha Ltd.) dispersed in water, 31.5 g of a titanium oxide sol
(CSB, TiO.sub.2 content: 38% by weight, manufactured by Sakai
Chemical Industry Co., Ltd.) and water. The kneaded one was dried
at 60.degree. C. and the resultant was molded into a rod-shaped
solid. This rod-shaped solid was dried at 60.degree. C. for 4 hours
to obtain 64.3 g of a white solid. The resulting solid was heated
to 500.degree. C. under air over 3 hours and calcined at the same
temperature for 5 hours to obtain 48.5 g of a white rod-shaped
titanium oxide cattier. Then, the resulting solid was ground to
obtain 28.0 g of a solid having a particle size of 8.6-16 mesh.
[0577] Then, 5.1 g of the titanium oxide carrier thus obtained was
taken out and was impregnated with a 0.5N potassium hydroxide
solution until water oozed out on the surface of the carrier, and
then dried at 60.degree. C. for 2 hour. The impregnation amount of
the aqueous potassium hydroxide solution was 3.6 g at this times.
The resulting carrier was impregnated with a solution prepared by
dissolving 0.71 g of commercially available ruthenium chloride
hydrate (RuCl.sub.3.nH.sub.2O, Ru content: 35.5% by weight) in 3.0
g of ethanol, and immediately dried at 60.degree. C. for 2 hours,
thereby to support ruthenium chloride. Then, a solution of 0.55 g
of sodium boron hydride (NaBH.sub.4), 2.0 g of water and 42.3 g of
ethanol was prepared. After the solution was sufficiently cooled in
an ice bath, an already prepared ruthenium chloride supported on
titanium oxide was added and ruthenium chloride was reduced. At
this time, bubbling was observed in the solution. After the
bubbling was terminated, the supernatant was removed by
decantation. 200 ml of water was added to the reduced solid,
followed by decantation. This operation was repeated five times.
After adding 200 ml of water, the pH was 9.2. The pH was then
adjusted to 6.7 by pouring 3.6 g of 0. 1N HCl into this solution.
The supernatant was removed by decantation. After washing again
with 500 ml of pure water for 30 minutes, the solid was separated
by filtration. This operation was repeated five times. Then, this
solid was dried at 60.degree. C. for 4 hours to obtain 5.2 g of a
bluish black solid. Then, this solid was impregnated with a
solution prepared by dissolving 0.63 g of potassium chloride in 3.2
g of pure water, and dried at 60.degree. C. for 4 hours. The dried
one was heated to 350.degree. C. under air over 1 hour and calcined
at the same temperature for 3 hours. Then, the calcined solid was
washed with 500 ml of pure water and then separated by filtration.
This operation was repeated five times. After adding dropwise an
aqueous silver nitrate solution to the filtrate, it was confirmed
that potassium chloride is not remained. After washing, the solid
was dried 60.degree. C. for 4 hours to obtain 5.1 g of a bluish
black ruthenium oxide catalyst supported on titanium oxide having a
particle size of 8.6-16 mesh. The pore radius of the resulting
catalyst was within a range from 0.04 to 6 micrometer. The pore
distribution curve of this catalyst measured by a mercury
porosimeter is shown in FIG. 6.
[0578] Furthermore, the thickness of the RuO.sub.2 layer was
measured by using a magnifying glass having graduation As a result,
ruthenium oxide was supported at the location which is 0.3 mm from
the outer surface. The measured particle size of the catalyst was
1.5 mm. With respect to the range S/L wherein ruthenium oxide is
supported on the surface of the catalyst, L and S were determined
as described above. As a result, the calculated value of S/L was
0.2.
[0579] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.2% by weight
[0580] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0581] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube in the same manner as that in Example 2 and that the hydrogen
chloride gas (195 ml/min.) and the oxygen gas (198 ml/min.) was
passed through the reaction tube, the reaction was conducted. 2.0
Hours after the beginning of the reaction, the formation activity
of chlorine per unit weight of the catalyst was
4.30.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 25
[0582] A catalyst was prepared by the following process. That is,
5.1 g of a spherical (1-2 mm .phi. in size) titanium oxide carrier
(CS300S-12, manufactured by Sakai Chemical Industry Co., Ltd.) was
impregnated with a 2 mol/l ammonium hydrogencarbonate solution
until water oozed out on the surface of the carrier, and then dried
at 60.degree. C. for 2 hour. The resulting carrier was impregnated
with a solution prepared by dissolving 0.71 g of commercially
available ruthenium chloride hydrate (RuCl.sub.3.nH.sub.2O, Ru
content: 35.5% by weight) in 2.2 g of ethanol, and immediately
dried at 60.degree. C. for 2 hours, thereby to support ruthenium
chloride. Then, a solution of 0.50 g of sodium boron hydride
(NaBH.sub.4) and 60.9 g of ethanol was prepared. After the solution
was sufficiently cooled in an ice bath, an already prepared
ruthenium chloride supported on titanium oxide was added and
ruthenium chloride was reduced. At this time, bubbling was observed
in the solution. After the bubbling was terminated, the supernatant
was removed by decantation. 200 ml of water was added to the
reduced solid, followed by decantation. This operation was repeated
five times. After adding 200 ml of water, the pH was 4.5. The added
pure water was removed by decantation. After washing again with 500
ml of pure water for 30 minutes, the solid was separated by
filtration. This operation was repeated five times. The pH of the
wash at the fifth time was 5.2. Then, this solid was dried at
60.degree. C. for 4 hours to obtain 5.4 g of a bluish black solid.
Then, this solid was impregnated with a solution prepared by
dissolving 0.19 g of potassium chloride in 1.9 g of pure water, and
dried at 60.degree. C. for 4 hours. The dried one was heated to
350.degree. C. under air over 1 hour and calcined at the same
temperature for 3 hours. Then, the calcined solid was washed with
500 ml of pure water for 30 minutes and then separated by
filtration. This operation was repeated five times. After adding
dropwise an aqueous silver nitrate solution to the filtrate, it was
confirmed that potassium chloride is not remained. After washing,
the solid was dried 60.degree. C. for 4 hours to obtain 5.4 g of a
black ruthenium oxide catalyst supported on titanium oxide.
Furthermore, the thickness of the RuO.sub.2 layer was measured by
EPMA. As a result, ruthenium oxide was supported at the location
which is 0.15-0.25 mm from the outer surface. The measured particle
size of the catalyst was within a range from 1.4 to 1.6 mm.
[0583] The calculated value of the range S/L wherein ruthenium
oxide is supported on the surface of the catalyst was within a
range from 0.09 to 0.18.
[0584] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.1% by weight
[0585] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.6% by weight
[0586] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube in the same manner as that in Example 2 and that the hydrogen
chloride as (187 ml/min.) and the oxygen gas (199 ml/min.) was
passed through the reaction tube and the internal temperature was
adjusted to 302.degree. C., the reaction was conducted. 2.0 Hours
after the beginning of the reaction, the formation activity of
chlorine per unit weight of the catalyst was 4.47.times.10.sup.-4
mol/min.g-catalyst.
EXAMPLE 26
[0587] A catalyst was prepared by the following process. That is,
5.0 g of a spherical (1-2 mm .phi. in size) titanium oxide carrier
(CS300S-12, manufactured by Sakai Chemical Industry Co., Ltd.) was
impregnated with a 2 mol/l ammonium carbonate solution until water
oozed out on the surface of the carrier, and then dried at
60.degree. C. for 2 hours. The resulting carrier was impregnated
with a solution prepared by dissolving 0.70 g of commercially
available ruthenium chloride hydrate (RuCl.sub.3.nH.sub.2O, Ru
content: 35.5% by weight) in 1.5 g of ethanol, and immediately
dried at 60.degree. C. for 2 hours, thereby to support ruthenium
chloride. Then, a solution of 0.50 g of sodium boron hydride
(NaBH.sub.4), 2.1 g of water and 41.1 g of ethanol was prepared.
After the solution was sufficiently cooled in an ice bath, an
already prepared ruthenium chloride supported on titanium oxide was
added and ruthenium chloride was reduced. At this time, bubbling
was observed in the solution. After the bubbling was terminated,
the supernatant was removed by decantation. 200 ml of water was
added to the reduced solid, followed by decantation. This operation
was repeated five times. After adding 200 ml of water, the pH was
3.9. The added pure water was removed by decantation. After washing
again with 500 ml of pure water for 30 minutes, the solid was
separated by filtration. This operation was repeated five times.
The pH of the wash at the fifth time was 5.6. Then, this solid was
dried at 60.degree. C. for 4 hours to obtain 5.3 g of a black
solid. Then, this solid was impregnated with a solution prepared by
dissolving 0.19 g of potassium chloride in 1.9 g of pure water, and
dried at 60.degree. C. for 4 hours. The dried one was heated to
350.degree. C. under air over 1 hour and calcined at the same
temperature for 3 hours. Then, the calcined solid was washed with
500 ml of pure water and then separated by filtration. This
operation was repeated five times. After adding dropwise an aqueous
silver nitrate solution to the filtrate, it was confirmed that
potassium chloride is not remained. After washing, the solid was
dried 60.degree. C. for 4 hours to obtain 5.2 g of a black
ruthenium oxide catalyst supported on titanium oxide. Furthermore,
the thickness of the RuO.sub.2 layer was measured by EPMA. As a
result, ruthenium oxide was supported at the location which is
0.19-0.30 mm from the outer surface. The measured particle size of
the catalyst was within a range from 1.5 to 1.6 mm.
[0588] The calculated value of the range S/L wherein ruthenium
oxide is supported on the surface of the catalyst was within a
range from 0.13 to 0.19.
[0589] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.2% by weight
[0590] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0591] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube in the same manner as that in Example 2 and that the hydrogen
chloride as (187 ml/min.) and the oxygen gas (199 ml/min.) was
passed through the reaction tube, the reaction was conducted. 2.0
Hours after the beginning of the reaction, the formation activity
of chlorine per unit weight of the catalyst was
4.34.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 27
[0592] A catalyst was prepared by the following process. That is,
5.0 g of a spherical (1-2 mm .phi. in size) titanium oxide carrier
(CS30OS-12, manufactured by Sakai Chemical Industry Co., Ltd.) was
impregnated with a 2. ON potassium hydroxide solution until water
oozed out on the surface of the carrier, and then dried at
60.degree. C. for 2 hours. The resulting carrier was impregnated
with a solution prepared by dissolving 0.71 g of commercially
available ruthenium chloride hydrate (RuCl.sub.3.nH.sub.2O, Ru
content: 35.5% by weight) in 3.0 g of ethanol, and immediately
dried at 60.degree. C. for 2 hours, thereby to support ruthenium
chloride. Then, a solution of 0.57 g of sodium boron hydride
(NaBH.sub.4), 2.0 g of water and 42.5 g of ethanol was prepared.
After the solution was sufficiently cooled in an ice bath, an
already prepared ruthenium chloride supported on titanium oxide was
added and ruthenium chloride was reduced. At this time, bubbling
was observed in the solution. After the bubbling was terminated,
the supernatant was removed by decantation. 200 ml of water was
added to the reduced solid, followed by decantation. This operation
was repeated five times. After washing again with 500 ml of pure
water for 30minutes, the solid was separated by filtration. This
operation was repeated five times. Then, this solid was dried at
60.degree. C. for 4 hours to obtain 5.1 g of a black solid. Then,
this solid was impregnated with a solution prepared by dissolving
0.19 g of potassium chloride in 1.8 g of pure water, and dried at
60.degree. C. for 4 hours. The dried one was heated to 350.degree.
C. under air over 1 hour and calcined at the same temperature for 3
hours. Then, the calcined solid was washed with 500 ml of pure
water for 30 minutes and then separated by filtration. This
operation was repeated five times. After adding dropwise an aqueous
silver nitrate solution to the filtrate, it was confirmed that
potassium chloride is not remained. After washing, the solid was
dried 60.degree. C. for 4 hours to obtain 5.1 g of a black
ruthenium oxide catalyst supported on titanium oxide. Furthermore,
the thickness of the RuO.sub.2 layer was measured by EPMA. As a
result, ruthenium oxide was supported at the location which is
0.11-0.18 mm from the outer surface. The measured particle size of
the catalyst was within a range from 1.5 to 1.7 mm.
[0593] The calculated value of the range S/L wherein ruthenium
oxide is supported on the surface of the catalyst was within a
range from 0.06 to 0.11.
[0594] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.2% by weight
[0595] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0596] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in a reaction
tube in the same manner as that in Example 2 and that the hydrogen
chloride as (187 ml/min.) and the oxygen gas (199 ml/min.) was
passed through the reaction tube, the reaction was conducted. 2.0
Hours after the beginning of the reaction, the formation activity
of chlorine per unit weight of the catalyst was
4.29.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 28
[0597] A catalyst was prepared by the following process. That is,
122 g of chromium nitrate enneahydrate was dissolved in 600 ml of
pure water and the solution was heated to 42.degree. C. Then, 130 g
of 25 wt % ammonia water was added dropwise over 2 hours with
stirring, followed by stirring at the same temperature for
additional 30 minutes. The formed precipitate was separate by
filtration under reduced pressure. 1 liter of water was added to
the formed precipitate, followed by stirring and further filtration
under reduced pressure. After the precipitate was washed by
repeating this operation five times, and then dried at 60.degree.
C. to obtain a bluish green solid. The resulting bluish green solid
was ground, and heated under air from room temperature to
375.degree. C. over 1 hour, and then calcined at the same
temperature for 3 hours to obtain 23.5 g of a black chromium oxide
powder.
[0598] Then, 0.89 g of commercially available ruthenium chloride
hydrate (RuCl.sub.3.nH.sub.2O, Ru content: 35.5% by weight) was
dissolved in 2.16 g of pure water to obtain an aqueous ruthenium
chloride solution. 1.64 g of the resulting aqueous solution was
added dropwise until the pores of the 6.0 g of chromium oxide are
nearly impregnated with the aqueous solution, followed by drying at
60.degree. C. Then, 1.40 g of the remaining aqueous ruthenium
chloride solution was added dropwise to the chromium oxide carrier,
thereby to support the total amount of ruthenium chloride by
impregnation to obtain a black powder. The resulting black powder
was dried in an air at 60.degree. C., heated under air from room
temperature to 350.degree. C. over 1 hour, and then calcined at the
same temperature for 3 hours to obtain 6.3 g of a black powder. The
resulting powder was molded to adjust the particle size to 12-18.5
mesh, thereby to obtain a calcined catalyst of ruthenium chloride
supported on chromium oxide.
[0599] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.5% by weight
[0600] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.9% by weight
[0601] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by sufficiently
mixing 2.5 g of the calcined ruthenium chloride supported on
chromium oxide thus obtained with 5 g of a titanium oxide carrier
adjusted to 12-18.5 mesh and then charged in a quartz reaction tube
(inner diameter: 12 mm) and that the hydrogen chloride gas (200
ml/min.) and the oxygen gas (200 ml/min.) were passed through the
reaction tube and the internal-temperature was adjusted to
301.degree. C., the reaction was conducted. 2.2 Hours after the
beginning of the reaction, the formation activity of chlorine per
unit weight of the catalyst was 6.1.times.10.sup.-4
mol/min.g-catalyst. The formation activity of chlorine per unit
weight of Ru was 124.times.10.sup.-4 mol/min.g-catalyst.
EXAMPLE 29
[0602] A catalyst was prepared by the following process. That is,
1.10 g of commercially available ruthenium chloride hydrate
(RuCl.sub.3.nH.sub.2O, Ru content: 35.5% by weight) was dissolved
in 1000 ml of an aqueous 0.1 mol/l hydrochloric acid solution, and
the solution was allowed to stand for 30 minutes. Then, 7.5 g of
the chromium oxide powder obtained in Example 30 was suspended in
this solution and the pH was adjusted to 4.5 by adding an aqueous
0.1 mol/l potassium hydroxide solution with stirring, thereby
precipitation -supporting ruthenium on chromium oxide Then, this
suspension was heated to 60.degree. C. with adjusting the pH to
4.5, and then stirred for 5 hours. After the completion of
stirring, the suspension was air-cooled to not more than 40.degree.
C., filtered under reduced pressure, and then dried at 60.degree.
C. to obtain a solid. The solid was ground, heated under air from
room temperature to 70.degree. C. over 1 hour, and then calcined at
the same temperature for 8 hours. The calcined one was heated under
air from room temperature to 375.degree. C. over 1 hour, and then
calcined at the same temperature for 8 hours. 7.6 g of the
resulting black powder was washed with 0.5 liter of pure water ten
times over 1 day, and then dried under air at 60.degree. C. over 8
hours to obtain 7.1 g of a black powder. The resulting powder was
molded to adjust the particle size to 12-18.5 mesh, thereby to
obtain a catalyst of ruthenium oxide supported on chromium
oxide.
[0603] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+Cr.sub.2O.sub.3).times.100=6.4% by weight
[0604] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+Cr.sub.2O.sub.3).times.100=4.9% by weight
[0605] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by sufficiently
mixing 2.5 g of the ruthenium oxide supported on chromium oxide
thus obtained with 5 g of a titanium oxide carrier adjusted to
12-18.5 mesh and then charged in a quartz reaction tube (inner
diameter: 12 mm) and that the hydrogen chloride gas (187 ml/min.)
and the oxygen gas (194 ml/min.) were passed through the reaction
tube, the reaction was conducted. 2.0 Hours after the beginning of
the reaction, the formation activity of chlorine per unit weight of
the catalyst was 4.75.times.10.sup.-4 mol/min.g-catalyst. The
formation activity of chlorine per unit weight of Ru was
97.6.times.10.sup.-4 mol/min.g-catalyst.
COMPARATIVE EXAMPLE 1
[0606] A catalyst was prepared by the following process. That is,
0.70 g of a commercially available ruthenium chloride hydrate
(RuCl.sub.3.3H.sub.20, Ru content: 35.5%) was dissolved in 4.0 g of
water. After the aqueous solution was sufficiently stirred, 5.0 g
of silica (Cariact G-10, manufactured by Fuji Silysia Chemical Co.,
Ltd.) obtained by adjusting a particle size to 12 to 18.5 mesh and
drying under air at 500.degree. C. for 1 hour, was impregnated with
the solution of ruthenium chloride dropwise, thereby to support
ruthenium chloride by impregnation. The supported one was heated
from room temperature to 100.degree. C. under a nitrogen flow (100
ml/min.) over 30 minutes, dried at the same temperature for 2
hours, and then air-cooled to room temperature to obtain a black
solid. The resulting solid was heated from room temperature to
250.degree. C. over 1 hour and 30 minutes under an air flow of 100
ml/min., dried at the same temperature for 3 hours and then
air-cooled to room temperature to obtain 5.37 g of black ruthenium
chloride catalyst supported on silica. Incidentally, the calculated
value of the content of ruthenium was as follows.
Ru/(RuCl.sub.3.3H.sub.2O+SiO.sub.2).times.100=4.5% by weight
[0607] According to the same manner as that described in Example 2
except that 2.5 g of the ruthenium chloride catalyst supported on
silica thus obtained was charged in a reaction tube without being
diluted with a titanium oxide carrier in the same manner as that in
Example 2 and that the hydrogen chloride gas (202 ml/min.) and the
oxygen gas (213 ml/min.) were passed through the reaction tube and
the internal temperature was adjusted to 300.degree. C., the
reaction was conducted. 1.7 Hours after the beginning of the
reaction, the formation activity of chlorine per unit weight of the
catalyst was 0.49.times.10.sup.-4 mol/min.g-catalyst.
COMPARATIVE EXAMPLE 2
[0608] A catalyst was prepared by the following process. That is,
8.0 g of a powder obtained by grinding a spherical titanium oxide
(CS-300, manufactured by Sakai Chemical Industry Co., Ltd.) in a
mortar was sufficiently mixed with 0.53 g of a ruthenium dioxide
powder (manufactured by NE Chemcat Co., Ltd.) with grinding in a
mortar, and then molded to adjust the particle size to 12-18.5
mesh, thereby to obtain a ruthenium oxide-titanium oxide mixed
catalyst. Incidentally, the calculated value of the content of
ruthenium oxide was 6.2% by weight. The calculated value of the
content of ruthenium was 4.7% by weight.
[0609] According to the same manner as that described in Example 2
except that 2.5 g of the ruthenium oxide- titanium oxide mixed
catalyst thus obtained was charged in the reaction tube in the same
manner as that in Example 2 and that the hydrogen chloride gas (199
ml/min.) and the oxygen gas (194 ml/min.) were passed through the
reaction tube and the internal temperature was adjusted to
299.degree. C., the reaction was conducted. 2.3 Hours after the
beginning of the reaction, the formation activity of chlorine per
unit weight of the catalyst was 0.83.times.10.sup.-4
mol/min.g-catalyst.
COMPARATIVE EXAMPLE 3
[0610] A catalyst was prepared by the following process. That is,
41.7 g of commercially available tetraethyl orthosilicate was
dissolved in 186 ml of ethanol and 56.8 g of titanium
tetraisopropoxide was poured into the solution. After stirring at
room temperature for 30 minutes, an aqueous solution which is
obtained by sufficiently mixing an aqueous 0.01 mol/l acetic acid
solution, prepared by dissolving 0.14 g of acetic acid in 233 ml of
pure water, with 93 ml of ethanol was added dropwise. As the
solution added dropwise, a white precipitate was produced. After
the completion of the dropwise addition, the solution was stirred
at room temperature for 1 hour, heated with stirring and then
refluxed on an oil bath at 102.degree. C. for 1 hour. The
temperature of the solution at this time was 80.degree. C. This
solution was air-cooled, filtered with a glass filer, washed with
500 ml of pure water and then filtered again. After this operation
was repeated twice, the resultant was dried under air at 60.degree.
C. for 4 hour, heated from room temperature to 550.degree. C. for
1.5 hour and then calcined at the same temperature for 3 hours to
obtain 27.4 g of a white solid. The resulting solid was ground to
obtain a titania silica powder.
[0611] The resulting titania silica powder (8.0 g) was impregnated
with a solution prepared by dissolving 1.13 g of a commercially
available ruthenium chloride hydrate (RuCl.sub.3.nH.sub.2O, Ru
content: 35.5%) in 8.2 g of water, followed by drying in air at
60.degree. C. for 1 hour to support ruthenium chloride. The
supported one was heated from room temperature to 300.degree. C.
under a mixed flow of hydrogen (50 ml/min.) and nitrogen (100
ml/min.) over 1.5 hour, reduced at the same temperature for 1 hour
and then air-cooled to room temperature to obtain 8.4 g of a
grayish brown metal ruthenium supported on titania silica
powder.
[0612] The resulting metal ruthenium supported on titania silica
powder (8.4 g) was heated from room temperature to 600.degree. C.
under air flow over 3 hours and 20 minutes and then calcined at the
same temperature for 3 hours to obtain 8.5 g of a gray powder. The
resulting powder was molded to adjust the particle size to 12 to
18.5 mesh, thereby to obtain a ruthenium oxide catalyst supported
on titania silica.
[0613] Incidentally, the calculated value of the content of
ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2+SiO.sub.2).times.100=6.2% by
weight
[0614] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2+SiO.sub.2).times.100=4.7% by weight
[0615] According to the same reaction manner as that described in
Example 2 except that the ruthenium oxide catalyst supported on
titania silica (2.5 g) thus obtained was charged in a reaction tube
without diluting with the titanium oxide carrier in the same manner
as that described in Example 2 and that the hydrogen chloride gas
(180 ml/min.) and the oxygen gas (180 ml/min.) were passed through
the reaction tube, the reaction was conducted. 1.8 Hours after the
beginning of the reaction, the formation activity of chlorine per
unit weight of the catalyst was 0.46.times.10.sup.-4
mol/min.g-catalyst.
COMPARATIVE EXAMPLE 4
[0616] A catalyst was prepared by the following process. That is,
60.3 g of chromium nitrate enneahydrate was dissolved in 600 ml of
water and the solution was heated to 45.degree. C. Then, 64.9 g of
25 wt % ammonia water was added dropwise over 1.5 hours with
stirring, followed by stirring at the same temperature for
additional 30 minutes. 3.3 liter of water was added to the formed
precipitate and, after allowing to stand overnight to cause
sedimentation, the supernatant was removed by decantation. Then,
2.7 liter of water was added, followed by stirring sufficiently for
30 minutes. The precipitate was washed by repeating this operation
five times. After the precipitate was washed, the supernatant was
removed by decantation. Then, 49 g of 20 wt % silica sol was added
and, after stirring, the mixture was evaporated to dryness at
60.degree. C. using a rotary evaporator. The resultant was dried at
60.degree. C. for 8 hours and then dried at 120.degree. C. for 6
hours to obtain a green solid. Then, this solid was calcined in air
at 600.degree. C. for 3 hours and then molded to obtain a
Cr.sub.2O.sub.3-SiO.sub.2 catalyst of 12.5 to 18 mesh.
[0617] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the Cr.sub.2O.sub.3-SiO.sub.2
catalyst thus obtained was charged in the reaction tube without
being diluted with a titanium oxide carrier in the same manner as
that described in Example 2 and that the oxygen gas (200 ml/min.)
was passed through the reaction tube and the internal temperature
was adjusted to 301.degree. C., the reaction was conducted. 3.7
Hours after the beginning of the reaction, the formation activity
of chlorine per unit weight of the catalyst was
0.19.times.10.sup.-4 mol/min.g-catalyst.
COMPARATIVE EXAMPLE 5
[0618] A catalyst was prepared by the following process. That is,
10.1 g of a spherical (1-2 mm in size) titanium oxide carrier
(CS-300S-12, manufactured by Sakai Chemical Industry Co., Ltd.) was
impregnated with a solution prepared previously by dissolving 1.34
g of commercially available ruthenium chloride
(RuCl.sub.3.nH.sub.2O, Ru content: 37.3% by weight) in 3.7 g of
pure water, and then dried at 60.degree. C. for 4 hours. As a
result, a blackish brown solid was obtained. To reduce this solid
with hydrogen, the solid was heated from room temperature to
250.degree. C. under a mixed gas flow of hydrogen (20 ml/min.) and
nitrogen (200 ml/min.) over 2 hours, and then reduced at the same
temperature for 8 hours. After the reduction, 10.3 g of a black
solid was obtained. Then, the resulting solid was heated to
350.degree. C. under air over 1 hour, and then calcined at the same
temperature for 3 hours. As a result, 10.6 g of a black ruthenium
oxide catalyst supported on titanium oxide was obtained.
Incidentally, the calculated value of the content of ruthenium
oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.1% by weight
[0619] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=4.7% by weight
[0620] X-ray diffraction analysis of the titanium oxide used was
conducted under the same conditions as those of Example 1. As a
result, the content of the rutile crystal was 0%.
[0621] According to the same reaction manner as that described in
Example 2 except that 2.5 g of the ruthenium oxide catalyst
supported on titanium oxide thus obtained was charged in the
reaction tube in the same manner as that described in Example 2 and
that the hydrogen chloride (187 ml/min.) and the oxygen gas (199
ml/min.) were passed through the reaction tube, the reaction was
conducted. 2.0 Hours after the beginning of the reaction, the
formation activity of chlorine per unit weight of the catalyst was
2.89.times.10.sup.-4 mol/min.g-catalyst.
COMPARATIVE EXAMPLE 6
[0622] A catalyst was prepared by the following process. That is,
10.0 g of a spherical (1-2 mm in size) 5 wt % supported metal
ruthenium-titanium oxide catalyst (manufactured by N.E. Chemcat
Co., Ltd.) was impregnated with an aqueous 0.5 mol/l of potassium
chloride solution until water oozed out on the surface of the
catalyst, and then dried at 60.degree. C. for 1 hour. This
operation was repeated twice. The impregnation amount of the
aqueous potassium chloride solution was 3.31 g at the first time,
and 3.24 g at the second time. The total amount was 6.55 g. The
calculated value of the molar ratio of potassium chloride to
ruthenium was 0.66. Then, the resulting solid was dried. The dried
one was heated to 350.degree. C. under air over 1 hour, and then
calcined at the same temperature for 3 hours. Then, the resulting
solid was washed with 500 ml of pure water for 30 minutes and
filtered off. This operation was repeated five times. An aqueus
silver nitrate solution was added dropwise to the filtrate and it
was confirmed that potassium chloride is not remained. After
washing, the solid was dried at 60.degree. C. for 4 hours to obtain
9.9 g of a spherical black ruthenium oxide catalyst supported on
titanium oxide. Incidentally, the calculated value of the content
of ruthenium oxide was as follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2).times.100=6.6% by weight
[0623] The calculated value of the content of ruthenium was as
follows.
Ru/(RuO.sub.2+TiO.sub.2).times.100=5.0% by weight
[0624] According to the same reaction manner as that described in
Example 2 except that the catalyst was diluted by sufficiently
mixing 2.5 g of the ruthenium oxide catalyst supported on titanium
oxide thus obtained with titanium oxide carrier and then charged in
a quartz reaction tube (inner diameter: 12 mm) and that the
hydrogen chloride (187 ml/min.) and the oxygen gas (199 ml/min.)
were passed through the reaction tube, the reaction was conducted.
2.0 Hours after the beginning of the reaction, the formation
activity of chlorine per unit weight of the catalyst was
4.03.times.10.sup.-4 mol/min.g-catalyst.
COMPARATIVE EXAMPLE 7
[0625] 40.1 g of a 6.6 wt % ruthenium oxide catalyst supported on
titanium oxide (anatase crystal) obtained in the same manner as
that described in Example 20 was charged in the same reaction tube
as that in Example 18, and then heated in the same salt bath. The
length of the catalyst bed was 9.2 cm.
[0626] Incidentally, the calculated value of the content of
ruthenium oxide as the active component (A) of the catalyst was
6.6% by weight.
[0627] According to the method for evaluation of the
controllability of the reaction temperature of Example 18, the
reaction was conducted. The hydrogen chloride gas (0.881/min.) and
the oxygen gas (0.53 1/min.) were supplied. 5.5 Hours after the
beginning of the reaction, the bath temperature became constant at
276.degree. C. and the internal temperature (hot spot) became
stable at 301.5.degree. C. The conversion of hydrogen chloride at
this time was 37%. Even after 50 minutes, the bath temperature was
constant at 277.degree. C. and the internal temperature was stable
at 302.3.degree. C. Then, the bath temperature was raised by
4.degree. C. in total over 55 minutes to make it constant at
281.degree. C. As a result, the internal temperature raised to
348.degree. C. and it became difficult to control the reaction
temperature. At the time when the internal temperature raised to
348.degree. C., supply of the reaction gas was stopped and the
reaction operation ended.
COMPARATIVE EXAMPLE 8
[0628] According to the same manner as that described in Example 20
except for using 65.3 g (51 ml) of a high purity quartz ball
(quartz glass (thermal conductivity of a solid phase at 227.degree.
C. is 1.6 W/m. .degree. C.) sphere of 2 mm in size, manufactured by
Nikkato Co.) wherein purity of SiO.sub.2 is not less than 99.99% in
place of .alpha.-alumina, a catalyst system was obtained. The
length of the catalyst bed in the same reaction tube as that in
Example 20 was 16.5 cm.
[0629] Incidentally, the calculated value of the content of
ruthenium oxide as the active component (A) of the catalyst was as
follows.
RuO.sub.2/(RuO.sub.2+TiO.sub.2(catalyst carrier component
)+SiO.sub.2) .times.100=0.86% by weight
[0630] Quartz glass used is not a component (B) because thermal
conductivity of a solid phase at 227.degree. C. is 1.6W/m. .degree.
C.
[0631] According to the same manner as that described in Example 22
except that the temperature of the electric furnace was controlled
so that the maximum temperature (hot spot) of the catalyst bed
becomes the same temperature as that in Example 22, the reaction
was conducted.
[0632] 1 Hour and 15 minutes after the beginning of the supply of
hydrogen chloride and oxygen, the temperature of the electric
furnace became constant at 297.degree. C. and the maximum
temperature (hot spot) of the catalyst bed became stable at
390.degree. C. at the point which is 4 cm from the catalyst bed
inlet and, furthermore, the temperature distribution of the
catalyst bed was as shown in FIG. 9. According to the same manner
as that described in Example 20, the formation amount of chlorine
and the amount of the non-reacted hydrogen chloride were measured.
As a result, the conversion of hydrogen chloride was 62.3% and the
formation efficiency of chlorine was 8.1 mol chlorine/l-catalyst
system.h. (Results are summarized in the Table.)
1 TABLE Formation Temperature Conversion efficiency of catalyst of
hydrogen of chlorine.sup.2) bed(.degree. C.) chloride.sup.1) (mol
chlorine/ (hot spot) (%) catalyst system .multidot. h) Example 20
391 74.9 14.9 comparative 390 62.3 8.1 Example 8 .sup.1)Conversion
of hydrogen chloride = ((mol formed chlorine per unit time .times.
2)/(mol supplied chlorine per unit time)) .times. 100
.sup.2)Formation efficiency of chlorine = (mol formed chlorine per
unit time)/(volume of charged catalyst system)
COMPARATIVE EXAMPLE 9
[0633] 121 g of a 6.6 wt % ruthenium oxide catalyst supported on
titanium oxide obtained in the same manner as that described in
Example 20 was charged in the same reaction tube as that in Example
21, and then heated in the same salt bath. The length of the
catalyst bed was 54 cm. Incidentally, the calculated value of the
content of ruthenium oxide as the active component (A) of the
catalyst was 6.6% by weight. According to the same method for
evaluation of the controllability of the reaction temperature of
Example 21, the reaction was conducted. The hydrogen.) chloride gas
(6.1 l/min.) and the oxygen gas (3.05 l/min.) where supplied.
[0634] 8.4 Hours after the beginning of the reaction, the bath
temperature became constant at 295.5.degree. C. and the internal
temperature (hot spot) became estable at 330.degree. C. Then, the
bath temperature was raiced by 5.5.degree. C. in total over 23
minutes to make it constant at 301.degree. C. As a result, the
internal temperature raised to 350.degree. C. and it became
difficult to control the reaction temperature. At the time when the
internal temperature raised to 350.degree. C., supply of the
reaction gas was stoopped and the reaction operation ended.
* * * * *