U.S. patent application number 11/816584 was filed with the patent office on 2009-01-22 for palladium-containing catalyst, method for producing same, and method for producing alpha, beta-unsaturated carboxylic acid.
This patent application is currently assigned to Mitsubishi Rayon co., Ltd.. Invention is credited to Yoshiyuki Himeno, Toshiki Matsui, Wataru Ninomiya, Ken Ooyachi, Toshiya Yasukawa.
Application Number | 20090023952 11/816584 |
Document ID | / |
Family ID | 36916514 |
Filed Date | 2009-01-22 |
United States Patent
Application |
20090023952 |
Kind Code |
A1 |
Yasukawa; Toshiya ; et
al. |
January 22, 2009 |
PALLADIUM-CONTAINING CATALYST, METHOD FOR PRODUCING SAME, AND
METHOD FOR PRODUCING ALPHA, BETA-UNSATURATED CARBOXYLIC ACID
Abstract
Disclosed is a palladium-containing catalyst which enables to
produce an .alpha.,.beta.-unsaturated carboxylic acid in high
selectivity from an olefin or an .alpha.,.beta.-unsaturated
aldehyde. Also disclosed are a method for producing such a catalyst
and a method for producing an .alpha.,.beta.-unsaturated carboxylic
acid using such a catalyst. Specifically disclosed is a
palladium-containing catalyst containing 0.001 to 0.25 mole of
antimony element to 1 mole of palladium element or a
palladium-containing catalyst containing palladium element which
composes a metal, tellurium element, and bismuth element.
Inventors: |
Yasukawa; Toshiya;
(Hiroshima, JP) ; Matsui; Toshiki; (Hiroshima,
JP) ; Ooyachi; Ken; (Hiroshima, JP) ; Himeno;
Yoshiyuki; (Hiroshima, JP) ; Ninomiya; Wataru;
(Hiroshima, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Mitsubishi Rayon co., Ltd.
Tokyo
JP
|
Family ID: |
36916514 |
Appl. No.: |
11/816584 |
Filed: |
February 17, 2006 |
PCT Filed: |
February 17, 2006 |
PCT NO: |
PCT/JP2006/302795 |
371 Date: |
August 17, 2007 |
Current U.S.
Class: |
562/524 ;
502/215; 502/339 |
Current CPC
Class: |
B01J 27/0576 20130101;
C07C 45/35 20130101; C07C 45/34 20130101; C07C 47/21 20130101; B01J
37/0201 20130101; C07C 45/34 20130101; B01J 37/16 20130101; C07C
57/04 20130101; C07C 47/232 20130101; C07C 47/22 20130101; C07C
45/34 20130101; B01J 35/002 20130101; B01J 23/6447 20130101; C07C
45/35 20130101; C07C 51/252 20130101; B01J 21/08 20130101; C07C
51/252 20130101; B01J 23/6445 20130101 |
Class at
Publication: |
562/524 ;
502/339; 502/215 |
International
Class: |
C07C 51/16 20060101
C07C051/16; B01J 23/44 20060101 B01J023/44; B01J 27/057 20060101
B01J027/057; B01J 23/64 20060101 B01J023/64 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2005 |
JP |
2005-042494 |
Mar 4, 2005 |
JP |
2005-060545 |
Nov 11, 2005 |
JP |
2005-327362 |
Claims
1. A palladium-containing catalyst for producing an
.alpha.,.beta.-unsaturated carboxylic acid from an olefin or an
.alpha.,.beta.-unsaturated aldehyde, comprising 0.001 to 0.25 mole
of antimony element to 1 mole of palladium element.
2. The palladium-containing catalyst according to claim 1, further
comprising 0.001 to 0.4 mole of tellurium element to 1 mole of
palladium element.
3. A palladium-containing catalyst for producing an
.alpha.,.beta.-unsaturated carboxylic acid from an olefin or an
.alpha.,.beta.-unsaturated aldehyde, comprising palladium element
which composes a metal, tellurium element, and bismuth element.
4. A method for producing the palladium-containing catalyst of
claim 1 comprising: reducing a compound containing palladium
element in an oxidized state with a reducing agent; and reducing a
compound containing antimony element in an oxidized state with a
reducing agent.
5. A method for producing the palladium-containing catalyst of
claim 3 comprising: reducing a compound containing palladium
element in an oxidized state, a compound containing tellurium
element in an oxidized state, and a compound containing bismuth
element in an oxidized state with a reducing agent.
6. A method for producing an .alpha.,.beta.-unsaturated carboxylic
acid comprising: carrying out oxidation of an olefin or an
.alpha.,.beta.-unsaturated aldehyde with molecular oxygen in a
liquid-phase using the palladium-containing catalyst of claim
1.
7. A method for producing the palladium-containing catalyst of
claim 2 comprising: reducing a compound containing palladium
element in an oxidized state with a reducing agent; and reducing a
compound containing antimony element in an oxidized state with a
reducing agent.
8. A method for producing an .alpha.,.beta.-unsaturated carboxylic
acid comprising: carrying out oxidation of an olefin or an
.alpha.,.beta.-unsaturated aldehyde with molecular oxygen in a
liquid-phase using the palladium-containing catalyst of claim
2.
9. A method for producing an .alpha.,.beta.-unsaturated carboxylic
acid comprising: carrying out oxidation of an olefin or an
.alpha.,.beta.-unsaturated aldehyde with molecular oxygen in a
liquid-phase using the palladium-containing catalyst of claim 3.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for producing a
palladium-containing catalyst to produce an
.alpha.,.beta.-unsaturated carboxylic acid from an olefin or an
.alpha.,.beta.-unsaturated aldehyde, and a method for producing the
palladium-containing catalyst, and a method for producing the
.alpha.,.beta.-unsaturated carboxylic acid.
BACKGROUND ART
[0002] There are many industrially useful materials among
.alpha.,.beta.-unsaturated carboxylic acids. For example, acrylic
acid and methacrylic acid are quite largely used for raw materials
of synthetic resins and the like.
[0003] As a method for producing an .alpha.,.beta.-unsaturated
carboxylic acid, a method of liquid-phase oxidation of an olefin or
an .alpha.,.beta.-unsaturated aldehyde with molecular oxygen has
been researched. As a catalyst for producing the
.alpha.,.beta.-unsaturated carboxylic acid through liquid-phase
oxidation of the olefin or the .alpha.,.beta.-unsaturated aldehyde
with molecular oxygen, for example, a palladium-containing catalyst
is proposed in Patent Document 1. Further, as the catalyst for
producing the .alpha.,.beta.-unsaturated carboxylic acid through
liquid-phase oxidation of the olefin with molecular oxygen, a
palladium-containing catalyst which contains an intermetallic
compound between palladium and lead, bismuth, thallium or mercury
is proposed in Patent Document 2.
[0004] As a palladium-containing catalyst suitable for producing
benzyl acetate, though not for producing a carboxylic acid, a
catalyst having an atomic ratio of palladium/bismuth being 3/1.4 to
3/0.8 for producing a carboxylic acid ester is proposed in Patent
Document 3. A catalyst having an atomic ratio of palladium/bismuth
being 2.5 to 3.5 for producing benzyl acetate is proposed in Patent
Document 4. [0005] Patent Document 1: Japanese Patent Application
Laid-Open No. 2004-141,863 [0006] Patent Document 2: Japanese
Patent Application Laid-Open No. Sho 56-59,722 [0007] Patent
Document 3: Japanese Patent Application Laid-Open No. Hei
10-263,399 [0008] Patent Document 4: Japanese Patent Application
Laid-Open No. Hei 10-7,616
DISCLOSURE OF INVENTION
Problem to be Solved by the Invention
[0009] However, selectivities to the target
.alpha.,.beta.-unsaturated carboxylic acid in a liquid-phase
oxidation using the palladium-containing catalysts described in
Patent Documents 1 and 2 were not sufficient and a further
improvement of the selectivity has been desired. Further, when the
catalysts described in Patent Documents 3 and 4 were used as a
substitute for the catalyst for producing the
.alpha.,.beta.-unsaturated carboxylic acid through liquid-phase
oxidation of the olefin or the .alpha.,.beta.-unsaturated aldehyde
with molecular oxygen, the selectivities to the
.alpha.,.beta.-unsaturated carboxylic acid were, in many cases, not
high.
[0010] Further, in the liquid-phase oxidations using the foregoing
catalysts, a large amount of carbon dioxide was formed as a
by-product. Consequently, a catalyst which can suppress the
selectivity to carbon dioxide has been desired because the
selectivity to the .alpha.,.beta.-unsaturated carboxylic acid was
lowered as the selectivity to carbon dioxide became high.
[0011] Therefore, it is an object of the present invention to
provide a palladium-containing catalyst which enables to produce an
.alpha.,.beta.-unsaturated carboxylic acid in high selectivity from
an olefin or an .alpha.,.beta.-unsaturated aldehyde. It is another
object of the present invention to provide a method for producing
such a catalyst. It is also another object of the present invention
to provide a method for producing an .alpha.,.beta.-unsaturated
carboxylic acid using such a catalyst.
Means for Solving the Problem
[0012] One aspect of the present invention is a
palladium-containing catalyst for producing an
.alpha.,.beta.-unsaturated carboxylic acid from an olefin or an
.alpha.,.beta.-unsaturated aldehyde, in which the
palladium-containing catalyst is either the following (i) or the
following (ii).
[0013] (i) a palladium-containing catalyst including 0.001 to 0.25
mole of antimony element to 1 mole of palladium element,
[0014] (ii) a palladium-containing catalyst including palladium
element which composes a metal, tellurium element, and bismuth
element.
[0015] The palladium-containing catalyst of the foregoing (i) may
further include 0.001 to 0.4 mole of tellurium element to 1 mole of
palladium element. The palladium-containing catalyst of the
foregoing (i) can be produced by a method comprising the steps of
reducing a compound containing palladium element in an oxidized
state with a reducing agent, and reducing a compound containing
antimony element in an oxidized state with a reducing agent.
[0016] The palladium-containing catalyst of the foregoing (ii) can
be produced by a method comprising the step of reducing a compound
containing palladium element in an oxidized state, a compound
containing tellurium element in an oxidized state, and a compound
containing bismuth element in an oxidized state with a reducing
agent.
[0017] Further, another aspect of the present invention is a method
for producing an .alpha.,.beta.-unsaturated carboxylic acid,
comprising the step of:
[0018] carrying out oxidation of an olefin or an
.alpha.,.beta.-unsaturated aldehyde with molecular oxygen in a
liquid-phase using the foregoing palladium-containing catalyst.
EFFECT OF THE INVENTION
[0019] According to the present invention, a palladium-containing
catalyst which enables to produce an .alpha.,.beta.-unsaturated
carboxylic acid in high selectivity from an olefin or an
.alpha.,.beta.-unsaturated aldehyde can be provided. Further, the
.alpha.,.beta.-unsaturated carboxylic acid can be produced in high
selectivity by using the palladium-containing catalyst. Further, a
formation of carbon dioxide which is a by-product can be
reduced.
BEST MODE FOR CARRYING OUT THE INVENTION
[0020] The palladium-containing catalyst of the present invention
(hereinafter, also abbreviated to "catalyst") is a catalyst for
producing the .alpha.,.beta.-unsaturated carboxylic acid through
liquid-phase oxidation of the olefin or the
.alpha.,.beta.-unsaturated aldehyde with molecular oxygen
(hereinafter, also abbreviated to "liquid-phase oxidation").
(The First Embodiment of the Palladium-Containing Catalyst)
[0021] The first embodiment of the palladium-containing catalyst of
the present invention is the one comprising 0.001 to 0.25 mole of
antimony element to 1 mole of palladium element. It is preferable
that the catalyst further comprise 0.001 to 0.4 mole of tellurium
element to 1 mole of palladium element.
[0022] It is preferable that palladium element contained in the
catalyst be in a metallic state of 0 valence sate. It is preferable
that antimony element contained in the catalyst be in an oxidized
state of +3, +4, or +5 valence state, or in a metallic state of 0
valence state. It is preferable that tellurium element contained in
the catalyst in some cases be in an oxidized state of +6 or +4
valence state, or in a metallic state of 0 valence state.
[0023] The catalyst becomes capable of producing the
.alpha.,.beta.-unsaturated carboxylic acid in high selectivity from
the olefin or the .alpha.,.beta.-unsaturated aldehyde by adjusting
the number of moles of antimony element to 1 mole of palladium
element in the catalyst (namely, molar ratio of antimony element to
palladium element: Sb/Pd) to a predetermined range. The Sb/Pd is
preferably 0.005 to 0.25 and more preferably 0.01 to 0.23. Further,
the catalyst becomes capable of producing the
.alpha.,.beta.-unsaturated carboxylic acid in higher selectivity
from the olefin or the .alpha.,.beta.-unsaturated aldehyde by
adjusting the number of moles of tellurium element to 1 mole of
palladium element in the catalyst (namely, molar ratio of tellurium
element to palladium element: Te/Pd) to a predetermined range. The
Te/Pd is preferably 0.005 to 0.35 and more preferably 0.01 to 0.3.
The Sb/Pd and Te/Pd are adjustable by a compounding ratio of a
palladium compound, an antimony compound, and tellurium compound to
be used in the production of the palladium-containing catalyst and
the like.
[0024] The Sb/Pd can be calculated from masses and atomic weights
of antimony element and palladium element contained in the
catalyst. The masses of antimony element and palladium element
contained in the catalyst can be quantitatively determined by
elemental analysis. Further, in the case that the catalyst is
produced by a method like pore-filling method in which
substantially the whole amounts of palladium element and antimony
element contained in raw materials of palladium and antimony are
contained in the catalyst, masses of both the elements may be
calculated from a palladium content and a compounding amount of the
raw material of palladium to be used and a antimony content and a
compounding amount of the raw material of antimony to be used. The
Te/Pd can be quantitatively determined by the same method.
[0025] As the method for quantitatively determining the masses of
palladium element and antimony element in the catalyst by elemental
analysis, a method in which the following treatment A liquid and
treatment B liquid are prepared and analyzed can be listed. Mass of
tellurium element can be measured in the same way.
Preparation of a Treatment A Liquid:
[0026] Into a Teflon (registered trademark) decomposition tube, 0.2
g of the catalyst and predetermined amounts of concentrated nitric
acid, concentrated sulfuric acid, and hydrogen peroxide aqueous
solution are introduced, and a dissolving treatment is carried out
using a microwave digestion device (MARS5 (trade name) manufactured
by CEM Corporation). The resultant sample is filtrated and a
filtrate and washing water after used in washing are gathered and
filled up to a calibration mark on a measuring flask to make a
treatment A liquid.
Preparation of a Treatment B Liquid:
[0027] A filter paper on which the insoluble residue of the
treatment A liquid has been gathered is transferred into a platinum
crucible and is heated and burnt to ashes, and lithium metaborate
is added to it and fused with a gas burner. After cooled,
hydrochloric acid and a small amount of water are added to the
crucible, and after the fused material is dissolved, the resultant
solution is filled up to a calibration mark on a measuring flask to
make a treatment B liquid.
[0028] Each mass of antimony element and palladium element
contained in the treatment A liquid thus obtained and the treatment
B liquid thus obtained is determined quantitatively with ICP atomic
emission spectrometer (IRIS-Advantage (trade name) manufactured by
Thermo Elemental Co., Ltd.), and the mass of each element in the
catalyst can be obtained from a sum of masses of each element in
both the liquids.
[0029] Further, the catalyst of the present invention mentioned
above may be a nonsupported type, however, it is preferably a
supported type in which palladium element and antimony element, or
palladium element, antimony element, and tellurium element are
supported on a carrier. As the carrier, for example, activated
carbon, carbon black, silica, alumina, magnesia, calcia, titania or
zirconia can be listed. Among them, silica, alumina, magnesia,
calcia, titania or zirconia is more preferable, and silica, titania
or zirconia is particularly preferable. The carrier can be used
alone or two or more kinds of these carriers can be used. As the
case of two or more kinds of these carriers are used, for example,
a mixture such as a mixed oxide obtained by mixing silica and
alumina, and a complex oxide such as silica-alumina which is a
complex oxide can be listed.
[0030] A preferable specific surface area of the carrier cannot be
absolutely affirmed because it is variable depending on a kind of
carrier and the like. In the case of silica, the specific surface
area is preferably 50 m.sup.2/g or more and more preferably 100
m.sup.2/g or more, and preferably 1,500 m.sup.2/g or less and more
preferably 1,000 m.sup.2/g or less. As the specific surface area of
the carrier becomes smaller, a catalyst in which its useful
components (palladium element, antimony element) are supported more
on its surface can be produced, and as the specific surface area of
the carrier becomes larger, a catalyst in which its useful
components are supported more can be produced.
[0031] The pore volume of the carrier is not particularly limited,
however, it is preferably 0.1 cc/g or more and more preferably 0.2
cc/g or more, and preferably 2.0 cc/g or less and more preferably
1.5 cc/g or less.
[0032] The shape or size of the carrier is variable depending on
the shape or size of a reactor and not particularly limited, and
for example, various shapes such as powder, particle, sphere, and
pellet can be listed. Among them, particle and sphere which can be
easily operated in filtration and the like are preferable. In the
case that the carrier is powder or particle, the particle diameter
(median diameter) is preferably 0.5 .mu.m or more and more
preferably 1.0 .mu.m or more, and preferably 200 .mu.m or less and
more preferably 100 .mu.m or less. As the particle diameter of the
carrier becomes larger, separation of a catalyst and a reaction
liquid becomes easier, and as the particle diameter of the carrier
becomes smaller, dispersibility of the catalyst in the reaction
liquid becomes better.
[0033] In the case of a supported type catalyst, a total loading
ratio of palladium element and antimony element to a carrier is
preferably 0.1 to 40% by mass to the mass of the carrier before
these elements are supported, more preferably 0.5 to 30% by mass,
and furthermore preferably 1.0 to 20% by mass.
[0034] A loading ratio in the case of a supported type catalyst can
be calculated from the mass of each element obtained by the
foregoing method and the like and the mass of the carrier to be
used. Further, the mass of the carrier can also be quantitatively
determined by the following method. Namely, the catalyst is
transferred into a platinum crucible and fused after sodium
carbonate is added. To the resultant mixture, distilled water is
added to make a homogeneous solution and a quantitative
determination of a specific element in the resultant solution is
carried out with ICP atomic emission spectrometry. For example, in
the case of silica carrier, Si element is quantitatively
determined.
[0035] The catalyst of the present invention may contain another
metal element other than palladium element, antimony element, and
tellurium element. As the other metal element, for example,
platinum, rhodium, ruthenium, iridium, gold, silver, osmium,
copper, lead, bismuth, thallium, or mercury can be listed. One kind
or two or more kinds of the other metal elements can be included.
From the viewpoint of realizing high catalyst activity, the total
amount of palladium element, antimony element, and tellurium
element among the metal elements contained in the catalyst is
preferably 60% by mass or more and more preferably 80% by mass or
more.
[0036] The method for producing the catalyst of the present
invention will be explained.
[0037] The catalyst of the present invention can be suitably
produced by a method having a step of reducing a compound
containing palladium element in its oxidized state by a reducing
agent (hereinafter, also expressed as "Pd reducing step") and a
step of reducing a compound containing antimony element in its
oxidized state by a reducing agent (hereinafter, also expressed as
"Sb reducing step"). In the case of producing the catalyst further
containing tellurium element, the catalyst of the present invention
can be suitably produced by a method having the Pd reducing step,
the Sb reducing step, and a step of adding a compound containing
tellurium element (hereinafter, also expressed as "Te adding
step"). A step of reducing the compound containing tellurium
element may also be carried out after the Te adding step.
[0038] As the palladium compound containing palladium element in
its oxidized state (hereinafter, also expressed as "raw Pd"), for
example, a palladium salt, a palladium oxide, or a palladium oxide
alloy can be listed, and among them, the palladium salt is
preferable. As the palladium salt, for example, palladium chloride,
palladium acetate, palladium nitrate, palladium sulfate,
tetraamminepalladium chloride, or palladium bis(acetylacetonate)
can be listed, and among them, palladium chloride, palladium
acetate, palladium nitrate, or tetraamminepalladium chloride is
preferable.
[0039] As the antimony compound containing palladium element in its
oxidized state (hereinafter, also expressed as "raw Sb"), for
example, an antimony salt, antimony alkoxide, metaantimonic acid or
its salt, an organic antimony compound, or an antimony oxide can be
listed. As the antimony salt, for example, antimony fluoride,
antimony chloride, antimony bromide, antimony iodide, antimony
acetate, potassium antimonyl tartrate, antimony tartrate, or
antimony sulfide can be listed. As the antimony alkoxide, for
example, antimony methoxide, antimony ethoxide, antimony
isopropoxide, antimony butoxide, or antimony ethylene glycoxide can
be listed. As the metaantimonic acid salt, for example, ammonium
metaantimonate can be listed. As the organic antimony compound, for
example, triphenyl antimony can be listed. Among them, antimony
tartrate, ammonium metaantimonate, or the like is preferable.
[0040] As the tellurium compound containing tellurium element
(hereinafter, also expressed as "raw Te"), tellurium metal, a
tellurium salt, telluric acid or its salt, tellurous acid or its
salt, a tellurium oxide, or the like can be listed. As the
tellurium salt, for example, hydrogen telluride, tellurium
tetrachloride, tellurium dichloride, tellurium hexafluoride,
tellurium tetraiodide, tellurium tetrabromide, or tellurium
dibromide can be listed. As the tellurate, for example, sodium
tellurate or potassium tellurate can be listed. As the tellurite,
for example, sodium tellurite or potassium tellurite can be listed.
Among them, telluric acid or its salt, tellurous acid or its salt,
or a tellurium oxide is preferable. Tellurium element contained in
the raw Te may be in its oxidized state, reduced state, or metallic
state because reduction of the raw Te is not necessarily
indispensable.
[0041] Further, it is possible to use a compound containing two or
more kinds of palladium element, antimony element, and tellurium
element as a raw material of the catalyst, other than the method of
using the foregoing compounds. Concretely, for example, a
palladium-tellurium complex PdX.sub.n(TeRR').sub.4-n can be listed.
In the PdX.sub.n(TeRR').sub.4-n, Pd represents palladium, X
represents fluorine, chlorine, brome, or iodine, Te represents
tellurium, and each of R and R' independently represents an alkyl
group, and n represents an integer of 0 to 3. Further, it is also
possible to use a compound containing both of palladium element in
its oxidized state and antimony element in its oxidized state.
[0042] The foregoing raw Pd and raw Sb are properly selected and
used as the raw materials for producing the catalyst. The
compounding amounts of these compounds are properly selected so
that an Sb/Pd and loading ratios become predetermined values. In
the case of producing a catalyst containing tellurium element, the
foregoing raw Te is properly selected and used as the raw material
for producing the catalyst. The compounding amount of the raw Te is
properly selected so that a Te/Pd and loading ratios become
predetermined values.
[0043] Further, in the case of producing a catalyst containing
another metal element other than palladium element, antimony
element, and tellurium element, a compound containing the other
metal element (hereinafter, also expressed as "another raw
material") may be simultaneously used. As "another raw material",
for example, a metal, a metal oxide, a metal salt, a metal oxoacid,
and a metal oxoacid salt, which contains the other metal element,
can be listed.
[0044] A Pd reduction step and an Sb reduction step may be carried
out simultaneously or separately. When the respective reduction
steps are carried out separately, the order of the Pd reduction
step and the Sb reduction step is arbitrary. In the case that a Te
adding step is carried out, the Te adding step can be carried out
simultaneously with the Pd reduction step and/or the Sb reduction
step, or can be carried out in an arbitrary order. Further, in the
case that a catalyst containing another metal element other than
palladium element, antimony element, and tellurium element is
produced and a step of reducing "another raw material" in its
oxidized state with a reducing agent is carried out, the reducing
step can be carried out simultaneously with the Pd reduction step,
and/or the Sb reduction step, and/or Te adding step, or can be
carried out in an arbitrary order.
[0045] In the case of producing a supported type catalyst, it is
preferable to carry out the foregoing reduction step in the
presence of a carrier. As a method of reduction at the time of
producing the supported type catalyst, for example,
(1) a method in which a raw material containing a metal element in
its oxidized state is first supported on a carrier and then the
metal element is reduced by bringing the resultant carrier into
contact with a reducing agent; (2) a method in which a reducing
agent is brought into contact with a solution or slurry which
includes a raw material containing a metal atom in its oxidized
state, while the solution or slurry is in contact with a carrier,
and thereby the metal element is, at the same time, reduced and
supported on the carrier; and (3) a method in which the other metal
raw material is added after the method (2) is carried out; can be
listed. Among them, the reduction method (1) is preferable because
a catalyst having high dispersion of metal elements is easily
obtainable.
[0046] As the reduction method (1), a method in which firstly a
carrier is impregnated with a solution in which one kind or two or
more kinds of a raw Pd, a raw Sb, a raw Te, and "another raw
material" (hereinafter, collectively also expressed as "metal raw
materials") are dissolved in a solvent, and secondly the resultant
system is subjected to heat treatment to change the metal raw
materials into metal oxides, and then the metal oxides is reduced
by bringing the metal oxides supported on the carrier into contact
with a reducing agent is preferable. Further, in this method, it is
also possible to separately provide a step in which the metal raw
materials are supported on the carrier by evaporating the solvent
previous to the heat treatment.
[0047] In the method of producing the catalyst by impregnating the
solution to the carrier, a method in which the solvent is
evaporated after the carrier is soaked into the solution or a
method, what is called pore-filling method, in which the solvent is
evaporated after an amount of the solution equivalent to the pore
volume of the carrier is absorbed in the carrier is preferable. The
solvent of the solution is not particularly limited as long as it
can dissolve the metal raw materials. As the solvent for the metal
raw materials, for example, water; an organic carboxylic acid such
as acetic acid or valeric acid; an inorganic acid such as nitric
acid or hydrochloric acid; an alcohol such as ethanol, 1-propanol,
2-propanol, n-butanol or t-butanol; a ketone such as acetone,
methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone; a
hydrocarbon such as heptane, hexane or cyclohexane can be listed.
The solvent can be used alone or in combination of a plurality of
these solvents. As the solvent, water or the organic carboxylic
acid is preferable from the viewpoint of solubility of the metal
raw materials and the reducing agent or dispersibility of the
carrier.
[0048] As an operation of impregnation of the solution to the
carrier, it is possible to carry out the operation only once using
the solution containing all the metal raw materials, however, it is
also possible to carry out the operations in a plurality of times
using a plurality of the solutions. In the case of carrying out the
operations in a plurality of times, each operation of impregnation
after the first one may be carried out after any one of evaporation
of the solvent, heat treatment, or reduction of the preceding
operation. The order of supporting the metal elements is not
particularly limited.
[0049] A temperature of the heat treatment is preferably a
decomposition temperature at which the metal raw materials change
into metal oxides or above. A temperature of the heat treatment may
be the time which is sufficient for at least one part of the metal
raw materials to change into metal oxides and is preferably 1 to 12
hours.
[0050] As the reduction method (2), for example, a method in which
one kind or two or more kinds of the metal raw materials are
reduced by bringing a reducing agent into contact with a solution
or slurry in which the metal raw materials are dissolved or
dispersed, while the solution or slurry is impregnated to a
carrier, or a method in which the metal raw materials are reduced
by bringing the reducing agent into contact with the foregoing
solution or slurry while the carrier is dispersed in the solution
or slurry can be listed.
[0051] As an operation of bringing the reducing agent into contact
with the system to be reduced, it is possible to carry out the
operation only once using the solution containing all the metal raw
materials, however, it is also possible to carry out the operations
in a plurality of times using a plurality of the solutions. In the
case of carrying out the operations in a plurality of times, in
each reducing treatment after the first one, the carrier subjected
to the reducing treatment in the preceding reducing treatment is
used. The order of supporting the metal elements is not
particularly limited.
[0052] As the reduction method (3), for example, a method in which
a solution or slurry in which the other metal raw material is
separately dissolved or dispersed in a solvent such as water is
added to the solution or slurry existing after the metal raw
materials are reduced with the reducing agent in the presence of
the carrier is preferable. As the solvent for the solution or
slurry to be added, water is preferable, however, various organic
solvents as mentioned above may be used. A reducing agent may be
added again after the addition of the other metal raw material.
[0053] In the case of carrying out the reducing treatments in a
plurality of times, a kind of a reducing agent, a reducing
temperature and reducing time, or a kind of solvent in the case of
carrying out the reducing treatments in a liquid phase can be
properly set at each time independently.
[0054] In the present invention, it is preferable to reduce the raw
Pd at first by bringing a reducing agent into contact with a
solution of the raw Pd while the solution of the raw Pd and the
carrier are in contact with each other, and then to add to the
resultant system a solution in which the raw Sb (and the raw Te) is
dissolved in water or a slurry in which the raw Sb (and the raw Te)
is dispersed in water. Subsequently, the raw Sb (and the raw Te)
can be reduced, when it is needed.
[0055] The reducing agent to be used in the reduction is not
particularly limited, and for example, hydrazine, formaldehyde,
sodium borohydride, hydrogen, formic acid, a formic acid salt,
ethylene, propylene, 1-butene, 2-butene, isobutylene,
1,3-butadiene, 1-heptene, 1-hexene, 2-hexene, cyclohexene, allyl
alcohol, methacryl alcohol, acrolein, or methacrolein can be
listed. Among them, hydrazine, formaldehyde, hydrogen, formic acid,
or a formic acid salt is preferable. Further, two or more of these
reducing agents can be used together.
[0056] As the solvent to be used in the reduction in a liquid
phase, water is preferable, however, depending on dispersibility of
a carrier, an organic solvent like an alcohol such as ethanol,
1-propanol, 2-propanol, n-butanol, or t-butanol; a ketone such as
acetone, methyl ethyl ketone, methyl isobutyl ketone, or
cyclohexanone; an organic acid such as acetic acid, n-valeric acid,
or isovaleric acid; or a hydrocarbon such as heptane, hexane, or
cyclohexane can be used alone or in combination of a plurality of
these kinds. It is also possible to use a mixed solvent of water
and these solvents.
[0057] In the case that the reducing agent is gas, it is preferable
to carry out reduction in a pressure device such as an autoclave so
as to increase the solubility of the gas into a solution. On this
occasion, it is preferable to pressurize the inside of the pressure
device with the reducing agent. The pressure is preferably 0.1 to 1
MPa (gauge pressure; hereinafter, pressure being expressed in gauge
pressure).
[0058] Further, in the case that the reducing agent is a liquid,
there is no limitation to a device for carrying out reduction and
the reduction can be carried out by adding the reducing agent into
a solution. The amount of the reducing agent is not particularly
limited at this time, however, it is preferably 1 to 100 moles to 1
mole of palladium in its oxidized state.
[0059] The reduction temperature and the reduction time are
variable depending on metal raw materials or metal oxides which are
the objects to be reduced, reducing agents, and the like, however,
the reduction temperature is preferably -5 to 150.degree. C. and
more preferably 15 to 80.degree. C.
[0060] The reduction time is preferably 0.1 to 4 hours, more
preferably 0.25 to 3 hours, and furthermore preferably 0.5 to 2
hours.
[0061] When a supported type catalyst is produced using metal raw
materials to which reduction is not needed, the metal raw materials
may be supported on the carrier on which the foregoing reduction
has been carried out.
[0062] It is preferable to wash the resultant catalyst with water,
an organic solvent, or the like. Through the washing with water, an
organic solvent, or the like, impurities originated from metal raw
materials such as chlorides, acetate group, nitrate group, or
sulfate group, or those originated from reducing agents are
removed. The washing method and the number of times of washing are
not particularly limited, however, it is preferable to carry out
the washing to the extent that the impurities can be sufficiently
removed because it is apprehended that some impurities may impede
the liquid-phase oxidation reaction. The catalyst washed may be
directly used to the reaction after recovered by filtration,
centrifugation, or the like. Further, in the case that a Pd
reduction step and an Sb reduction step are carried out in separate
steps, it is also preferable to carry out washing between the
steps.
[0063] Further, the recovered catalyst may be dried. The drying
method is not particularly limited, however, it is preferable to
dry the recovered catalyst in air or in inert gas using dryer. It
is also possible to activate the dried catalyst before it is used
in the reaction, when it is needed. The method of activation is not
particularly limited, however, for example, a method in which heat
treatment of the catalyst is carried out under a reducing
atmosphere of hydrogen flow can be listed. According to this
method, oxide layer on the surface of palladium element or antimony
element and impurities that has not been removed in washing can be
removed.
(The Second Embodiment of the Palladium-Containing Catalyst)
[0064] The palladium-containing catalyst of the present invention
is the one comprising palladium element which composes a metal,
tellurium element, and bismuth element. The palladium-containing
catalyst becomes capable of producing an .alpha.,.beta.-unsaturated
carboxylic acid in high selectivity from an olefin or an
.alpha.,.beta.-unsaturated aldehyde by causing the catalyst to have
such a composition.
[0065] The fact that the palladium-containing catalyst comprises
palladium element that composes a metal can be measured with XRD
measurement, XPS (X ray photoelectron spectroscopy), and the like.
In XRD measurement, there exists a peak corresponding to (111) face
of palladium metal at about 40 degrees of X-ray diffraction angle
(2.theta.) in an X-ray powder diffraction pattern using Cu-K.alpha.
line. This peak is usually observed at 40.11 degrees, however, it
may shift toward lower angle by forming an alloy or an
intermetallic compound between palladium element in its metallic
state and tellurium element and/or bismuth element. In the present
invention, it is defined that the catalyst comprises palladium
element which composes a metal when a peak is observed at 39.0
degrees or above and 40.11 degrees or below as an X-ray diffraction
angle (2.theta.). It is preferable that the palladium element which
composes a metal be forming an alloy or an intermetallic compound
with tellurium element and/or bismuth element as mentioned above,
and it is more preferable that the catalyst comprise palladium
element having the X-ray diffraction angle (2.theta.) of 39.2
degrees or above. Further, it is preferable that the catalyst
comprise palladium element having the X-ray diffraction angle
(2.theta.) of 40.0 degrees or below, and more preferable that the
catalyst comprise palladium element having the X-ray diffraction
angle (2.theta.) of 39.9 degrees or below.
[0066] The molar ratio of tellurium element to palladium element
(Te/Pd) in the palladium-containing catalyst needs to exceed 0, and
it is preferably 0.002 or more, and more preferably 0.003 or more,
and the Te/Pd is preferably 0.30 or less, and more preferably 0.25
or less. The Te/Pd can be adjusted by a compounding ratio of each
raw material of palladium element and tellurium element, which is
used in the production of the palladium-containing catalyst as will
be mentioned later.
[0067] The chemical state of tellurium element contained in the
palladium-containing catalyst is not particularly limited and may
be either a metallic state or an oxidized state, however, tellurium
element is preferably in a metallic state because the electronic
state of palladium element which composes a metal is more changed.
Further, it is more preferable that tellurium element be forming an
alloy or an intermetallic compound with palladium element because a
proportion of palladium element, the electronic state of which has
drastically changed, becomes high by being adjacent to tellurium
element.
[0068] The molar ratio of bismuth element to palladium element
(Bi/Pd) in the palladium-containing catalyst needs to exceed 0, and
it is preferably 0.002 or more, and more preferably 0.003 or more,
and the Bi/Pd is preferably 0.26 or less, more preferably 0.10 or
less, and particularly preferably 0.06 or less. The Bi/Pd can be
adjusted by a compounding ratio of each raw material of palladium
element and bismuth element, which is used in the production of the
palladium-containing catalyst as will be mentioned later.
[0069] The chemical state of bismuth element contained in the
palladium-containing catalyst is not particularly limited and may
be either a metallic state or an oxidized state, however, bismuth
element is preferably in a metallic state because the electronic
state of palladium element which composes a metal is more changed.
Further, it is more preferable that bismuth element be forming an
alloy or an intermetallic compound with palladium element because a
proportion of palladium element, the electronic state of which has
drastically changed, becomes high by being adjacent to bismuth
element.
[0070] The sum of the Te/Pd and the Bi/Pd (i.e. (Te+Bi)/Pd) in the
palladium-containing catalyst needs to exceed 0, and it is
preferably 0.004 or more, and more preferably 0.006 or more, and
preferably 0.4 or less, and more preferably 0.3 or less to more
raise the selectivity to an .alpha.,.beta.-unsaturated carboxylic
acid and to more reduce the by-production of carbon dioxide.
[0071] The Te/Pd, Bi/Pd, and (Te+Bi)/Pd can be calculated from
masses and atomic weights of palladium element, tellurium element,
and bismuth element contained in the palladium-containing catalyst
which has been prepared. The masses of palladium element, tellurium
element, and bismuth element contained in the palladium-containing
catalyst can be measured by the following method.
Preparation of a Treatment A Liquid:
[0072] In the case that the carrier contains silica, the
palladium-containing catalyst, concentrated nitric acid, and 48% by
mass fluoric acid are introduced into a Teflon (registered
trademark) decomposition tube, and a dissolving treatment is
carried out using a microwave digestion device. In the case that
the carrier does not contain silica, the palladium-containing
catalyst, concentrated nitric acid, concentrated sulfuric acid, and
hydrogen peroxide aqueous solution are introduced into a Teflon
(registered trademark) decomposition tube, and a dissolving
treatment is carried out using a microwave digestion device. The
resultant sample is filtrated and a filtrate and washing water
after used in washing are gathered and filled up to a calibration
mark on a measuring flask to make a treatment A liquid.
Preparation of a Treatment B Liquid:
[0073] In the case that there is insoluble residue in the foregoing
treatment, a filter paper on which the insoluble residue has been
gathered is transferred into a platinum crucible and is heated and
burnt to ashes, and lithium metaborate is added to it and fused
with a gas burner. After cooled, hydrochloric acid and a small
amount of water are added to the crucible, and after the fused
material is dissolved, the resultant solution is filled up to a
calibration mark on a measuring flask to make a treatment B
liquid.
[0074] Each mass of palladium element, tellurium element and
bismuth element contained in the treatment A liquid and the
treatment B liquid is determined quantitatively with ICP atomic
emission spectrometer, and the mass of each element in the
palladium-containing catalyst can be obtained from a sum of masses
of each element in both the liquids.
[0075] The palladium-containing catalyst of the present invention
may contain another metal element. For example, a noble metal
element such as platinum, rhodium, ruthenium, iridium, gold,
silver, or osmium; and a base metal element such as antimony,
thallium, or lead can be listed. Two or more kinds of the other
metal elements can also be included. From the viewpoint of
realizing high catalyst activity, the total amount of palladium
element, tellurium element, and bismuth element among the metal
elements contained in the palladium-containing catalyst is
preferably 50% by mass or more.
[0076] The palladium-containing catalyst of the present invention
may be a nonsupported type, however, it is preferably a supported
type in which palladium element, tellurium element, and bismuth
element are supported on a carrier. As the carrier, for example,
activated carbon, carbon black, silica, alumina, magnesia, calcia,
titania or zirconia can be listed. Among them, silica, titania or
zirconia is preferable. A preferable specific surface area of the
carrier cannot be absolutely affirmed because it is variable
depending on a kind of carrier and the like. In the case of silica,
the specific surface area is preferably 50 m.sup.2/g or more and
more preferably 100 m.sup.2/g or more, and preferably 1,500
m.sup.2/g or less and more preferably 1,000 m.sup.2/g or less. As
the specific surface area of the carrier becomes smaller in the
above range, a catalyst in which its useful components (palladium
element, tellurium element, and bismuth element) are supported more
on its surface can be produced, and as the specific surface area of
the carrier becomes larger in the above range, a catalyst in which
its useful components are supported more can be produced.
[0077] In the case of a supported type catalyst, a total loading
ratio of palladium element, tellurium element, and bismuth element
is preferably 0.1% by mass or more to the mass of the carrier
before these elements are supported, more preferably 1% by mass or
more, furthermore preferably 2% by mass or more, and particularly
preferably 4% by mass or more, and preferably 40% by mass or less
to the mass of the carrier before these elements are supported,
more preferably 30% by mass or less, furthermore preferably 20% by
mass or less, and particularly preferably 15% by mass or less.
[0078] The palladium-containing catalyst of the present invention
can be produced using each metal of palladium element, tellurium
element, and bismuth element, an alloy of these elements, or a
compound containing these elements as a raw material. Among them,
the compound containing these elements is preferable as a raw
material because a high-activity catalyst in which useful
components are highly dispersed on a carrier can be easily
prepared.
[0079] The raw material of palladium element is not particularly
limited and palladium metal, a palladium salt, a palladium oxide,
or the like can be listed, however, among them, a palladium salt is
preferable. As a palladium salt, for example, palladium chloride,
palladium acetate, palladium nitrate, palladium sulfate,
tetraamminepalladium chloride, or palladium bis(acetylacetonate)
can be listed, and among them, palladium chloride, palladium
acetate, palladium nitrate, or tetraamminepalladium chloride is
preferable, and palladium nitrate is particularly preferable.
[0080] The raw material of tellurium element is not particularly
limited and tellurium metal, a tellurium salt, telluric acid or its
salt, tellurous acid or its salt, a tellurium oxide, or the like
can be listed. As the tellurium salt, for example, hydrogen
telluride, tellurium tetrachloride, tellurium dichloride, tellurium
hexafluoride, tellurium tetraiodide, tellurium tetrabromide, or
tellurium dibromide can be listed. As the tellurate, for example,
sodium tellurate or potassium tellurate can be listed. As the
tellurite, for example, sodium tellurite or potassium tellurite can
be listed. Among them, telluric acid or its salt, tellurous acid or
its salt, or a tellurium oxide is preferable.
[0081] The raw material of bismuth element is not particularly
limited and bismuth metal, a bismuth salt, an organic bismuth
compound, a bismuth oxide, or the like can be listed. As the
bismuth salt, for example, bismuth(III) acetate, bismuth(III)
acetate oxide, bismuth(III) bromide, basic bismuth(III) carbonate,
bismuth(III) chloride, bismuth(III) fluoride, bismuth(III) iodide,
basic bismuth(III) nitrate, bismuth(III) nitrate, bismuth(III)
oxychloride, bismuth(III) phosphate, or bismuth(III) sulfate can be
listed. As the organic bismuth compound, for example, triphenyl
bismuth can be listed. Among them, the bismuth oxide or bismuth
nitrate is preferable.
[0082] The foregoing raw materials of palladium element, tellurium
element, and bismuth element are properly selected as the raw
materials and used for producing the palladium-containing catalyst.
The compounding ratios of these compounds are properly selected so
that each molar ratio of palladium element, tellurium element and
bismuth element in the palladium-containing catalyst becomes an
objective value.
[0083] It is preferable to produce the palladium-containing
catalyst by selecting a compound containing palladium element in an
oxidized state, a compound containing tellurium element in an
oxidized state, and a compound containing bismuth element in an
oxidized state as raw materials of palladium element, tellurium
element and bismuth element, respectively, and mixing them, and
reducing the resultant mixture with a reducing agent.
[0084] Further, in the case of producing a supported type catalyst,
it can be achieved by causing the foregoing raw materials to be
supported on a carrier. The amount of the carrier to be used is
properly selected so as to obtain a catalyst having an objective
loading ratio.
[0085] The method for supporting the raw materials on a carrier is
not particularly limited and, for example, a precipitation method,
an ion-exchange method, an impregnation method, or a sedimentation
method can be listed. In the case of the impregnation method, the
raw materials of palladium element, tellurium element, and bismuth
element may be simultaneously impregnated and supported, or any of
the raw materials may be impregnated and supported, and then the
rest of the raw materials may be impregnated and supported.
[0086] Further, it may be carried out, after supporting the raw
materials of palladium element, tellurium element, and bismuth
element on a carrier, to subject the resultant carrier to heat
treatment to change it into the carrier on which palladium oxide,
tellurium oxide, and bismuth oxide are supported. As the
temperature range of the heat treatment, 200.degree. C. or above is
preferable and 300.degree. C. or above is more preferable, and
800.degree. C. or below is preferable and 700.degree. C. or below
is more preferable. The time of the heat treatment is not
particularly limited, however, it is preferably within the range
from 1 to 12 hours.
[0087] Subsequently, the palladium-containing catalyst is produced
by reducing palladium element in its oxidized state, tellurium
element in its oxidized state, and bismuth element in its oxidized
state, which are supported on the carrier, with a reducing
agent.
[0088] The reducing agent to be used is not particularly limited,
and for example, hydrazine, formaldehyde, sodium borohydride,
hydrogen, formic acid, a formic acid salt, ethylene, propylene,
1-butene, 2-butene, isobutylene, 1,3-butadiene, 1-heptene,
2-heptene, 1-hexene, 2-hexene, cyclohexene, allyl alcohol,
methallyl alcohol, acrolein, or methacrolein can be listed. Two or
more of these reducing agents can also be used together. When the
reduction is carried out in a gas-phase, hydrogen is preferable as
a reducing agent. Further, when the reduction is carried out in a
liquid phase, hydrazine, formaldehyde, formic acid, or a formic
acid salt is preferable as a reducing agent.
[0089] As the solvent to be used in the reduction in a liquid
phase, water is preferable, however, depending on dispersibility of
a carrier in the case of a supported type catalyst, an organic
solvent like an alcohol such as ethanol, 1-propanol, 2-propanol,
n-butanol, or t-butanol; a ketone such as acetone, methyl ethyl
ketone, methyl isobutyl ketone, or cyclohexanone; an organic acid
such as acetic acid, n-valeric acid, or isovaleric acid; or a
hydrocarbon such as heptane, hexane, or cyclohexane can be used
alone or in combination of plurality of these kinds. It is also
possible to use a mixed solvent of water and these solvents.
[0090] In the case that the reducing agent is a gas, it is
preferable to carry out reduction in a pressure device such as
autoclave so as to increase the solubility of the gas into a
solution. On this occasion, the inside of the pressure device is
pressurized with the reducing agent. The pressure is preferably 0.1
MPa or more and 1 MPa or less.
[0091] Further, in the case that the reducing agent is a liquid,
there is no limitation to a device for carrying out reduction and
the reduction can be carried out by adding the reducing agent into
a solution. On this occasion, the amount of the reducing agent to
be used is not particularly limited, however, it is preferably 1
mole or more and 100 moles or less to 1 mole of palladium in its
oxidized state.
[0092] The reduction temperature and the reduction time are
variable depending on reducing agents and the like, however, the
reduction temperature is preferably -5.degree. C. or above and more
preferably 15.degree. C. or above, and preferably 150.degree. C. or
below and more preferably 80.degree. C. or below. The reduction
time is preferably 0.1 hour or more, more preferably 0.25 hour or
more, and furthermore preferably 0.5 hour or more, and preferably 4
hours or less, more preferably 3 hours or less, and furthermore
preferably 2 hours or less.
[0093] It is preferable to wash the palladium-containing catalyst
prepared by the reduction with water, a solvent, or the like.
Through the washing with water, a solvent, or the like, impurities
originated from raw materials such as chlorides, acetate group,
nitrate group, or sulfate group, or those originated from reducing
agents are removed. The washing method and the number of times of
washing are not particularly limited, however, it is preferable to
carry out the washing to the extent that the impurities can be
sufficiently removed because it is apprehended that some impurities
may impede the liquid-phase oxidation reaction of a olefin or an
.alpha.,.beta.-unsaturated aldehyde. The catalyst washed may be
directly used to the reaction after recovered by filtration,
centrifugation, or the like.
[0094] Further, the recovered catalyst may be dried. The drying
method is not particularly limited, however, usually the recovered
catalyst is dried in air or in an inert gas using dryer. It is also
possible to activate the dried catalyst before it is used in the
liquid-phase oxidation reaction, when it is needed. The method of
activation is not particularly limited, however, for example, a
method in which heat treatment of the catalyst is carried out under
a reducing atmosphere of hydrogen flow can be listed. According to
this method, oxide layer on the surface of palladium element and
impurities that has not removed in washing can be removed. The
physical properties of the prepared catalyst can be confirmed with
BET specific surface area measurement, XRD measurement, CO pulse
adsorption method, TEM measurement, XPS measurement, and the
like.
[0095] Metal palladium by itself exhibits an activity as an
oxidation catalyst, however, it is not sufficient for the activity
of the reaction of producing an .alpha.,.beta.-unsaturated
carboxylic acid through oxidation of an olefin or an
.alpha.,.beta.-unsaturated aldehyde and a large quantity of carbon
dioxide as a by-product is formed. On the other hand, when bismuth
element having a different electronegativity from that of palladium
element is present, an electronic state of palladium element
changes through the function of bismuth element. Further, when
tellurium element having a different electronegativity from both of
palladium element and bismuth element is present, an electronic
state of palladium element further changes through the function of
tellurium element. As a result, the activity of the main reaction
in which an olefin or an .alpha.,.beta.-unsaturated aldehyde is
oxidized to produce an .alpha.,.beta.-unsaturated carboxylic acid
is raised while a side reaction in which carbon dioxide is formed
is suppressed.
(Method for Producing an .alpha.,.beta.-Unsaturated Carboxylic
Acid)
[0096] In the next place, a method for producing the
.alpha.,.beta.-unsaturated carboxylic acid through liquid-phase
oxidation of the olefin or the .alpha.,.beta.-unsaturated aldehyde
with molecular oxygen using the palladium-containing catalyst of
the present invention will be explained.
[0097] As the olefin which is a raw material, for example,
propylene, isobutylene, or 2-butene can be listed, and among them,
propylene or isobutylene is suitable. Two or more olefins can also
be used together. The olefin which is a raw material may contain a
small amount of a saturated hydrocarbon or a lower saturated
aldehyde or both of them as impurities.
[0098] The .alpha.,.beta.-unsaturated carboxylic acid to be
produced from the olefin is the one having the same carbon skeleton
as the olefin has. Concretely, in the case that the raw material is
propylene, acrylic acid is produced, and in the case that the raw
material is isobutylene, methacrylic acid is produced. Further,
usually, an .alpha.,.beta.-unsaturated aldehyde is simultaneously
obtained from the olefin. The .alpha.,.beta.-unsaturated aldehyde
has the same carbon skeleton as the olefin has. For example, in the
case that the raw material is propylene, acrolein is obtained, and
in the case that the raw material is isobutylene, methacrolein is
obtained.
[0099] As the .alpha.,.beta.-unsaturated aldehyde which is a raw
material, for example, acrolein, methacrolein, crotonaldehyde
(.beta.-methylacrolein), or cinnamaldehyde (.beta.-phenylacrolein)
can be listed. Among them, acrolein or methacrolein is suitable.
Two or more .alpha.,.beta.-unsaturated aldehydes can also be used
together. The .alpha.,.beta.-unsaturated aldehyde which is a raw
material may contain a small amount of a saturated hydrocarbon or a
lower saturated aldehyde or both of them as impurities.
[0100] The .alpha.,.beta.-unsaturated carboxylic acid to be
produced from the .alpha.,.beta.-unsaturated aldehyde is the one in
which the aldehyde group of the .alpha.,.beta.-unsaturated aldehyde
has changed into the carboxyl group. Concretely, in the case that
the raw material is acrolein, acrylic acid is obtained, and in the
case that the raw material is methacrolein, methacrylic acid is
obtained.
[0101] As a raw material of the liquid-phase oxidation, either an
olefin or an .alpha.,.beta.-unsaturated aldehyde or a mixture of
both of them may be used.
[0102] The liquid-phase oxidation reaction may be carried out by
either a continuous type operation or a batch type operation,
however, the continuous type operation is industrially preferable
in consideration of the productivity.
[0103] The source of molecular oxygen to be used in the
liquid-phase oxidation reaction is preferably air because it is
economical, however, pure oxygen or a mixed gas of pure oxygen and
air can be used, and if necessary, a diluted mixed gas in which air
or pure oxygen is diluted with nitrogen, carbon dioxide or water
vapor can also be used. It is preferable that such a molecular
oxygen-containing gas be ordinarily supplied into a reaction vessel
such as an autoclave under the pressurized state.
[0104] As the solvent to be used in the liquid phase oxidation
reaction, for example, it is preferable to use at least one organic
solvent selected from the group consisting of t-butanol,
cyclohexanol, acetone, methyl ethyl ketone, methyl isobutyl ketone,
acetic acid, propionic acid, n-butyric acid, isobutyric acid,
n-valeric acid, isovaleric acid, ethyl acetate, and methyl
propionate. Among them, at least one organic solvent selected from
the group consisting of t-butanol, methyl isobutyl ketone, acetic
acid, propionic acid, n-butyric acid, isobutyric acid, n-valeric
acid, and isovaleric acid is more preferable. Further, it is
preferable to cause water to coexist with the solvent to produce an
.alpha.,.beta.-unsaturated carboxylic acid in higher selectivity.
The amount of water to coexist is not particularly limited, and it
is preferably 2% by mass or more to the total mass of the solvent
and water, and more preferably 5% by mass or more, and preferably
70% by mass or less, and more preferably 50% by mass or less. In
the case of a mixed solvent of two or more kinds, the mixed solvent
is preferably homogeneous, but it may be heterogeneous.
[0105] The total concentration of the olefin and the
.alpha.,.beta.-unsaturated aldehyde which are the raw materials of
the liquid-phase oxidation reaction is preferably 0.1% by mass or
more to the solvent existing in the reactor, and more preferably
0.5% by mass or more, and preferably 30% by mass or less, and more
preferably 20% by mass or less.
[0106] The amount of the molecular oxygen to be used is preferably
0.1 mole or more to 1 mole of the total of the olefin and the
.alpha.,.beta.-unsaturated aldehyde which are the raw materials of
the liquid-phase oxidation reaction, more preferably 0.2 mole or
more, and furthermore preferably 0.3 mole or more, and preferably
20 moles or less, more preferably 15 moles or less, and furthermore
preferably 10 moles or less.
[0107] It is preferable that the catalyst be used in a suspended
state in the reaction liquid of the liquid-phase oxidation,
however, the catalyst may be used in a fixed bed. The amount of the
catalyst to be used is preferably 0.1% by mass or more to the
liquid existing in the reactor, more preferably 0.5% by mass or
more, and furthermore preferably 1% by mass or more, and preferably
30% by mass or less, more preferably 20% by mass or less, and
furthermore preferably 15% by mass or less.
[0108] The reaction temperature and the reaction pressure are
properly selected according to the solvent and the raw material to
be used. The reaction temperature is preferably 30.degree. C. or
more, and more preferably 50.degree. C. or more, and preferably
200.degree. C. or less, and more preferably 150.degree. C. or less.
Further, the reaction pressure is preferably atmospheric pressure
(0 MPa) or more, and more preferably 0.5 MPa or more, and
preferably 10 MPa or less, and more preferably 5 MPa or less.
EXAMPLES
[0109] Hereinafter, the present invention will be more concretely
explained by way of Examples and Comparative Examples, however, the
present invention is not limited to these Examples. In the
following Examples and Comparative Examples, "part(s)" means
"part(s) by mass".
(XRD Measurement)
[0110] The measurement was performed with RU-200A (trade name)
manufactured by Rigaku Corporation. The measuring conditions are:
X-ray; Cu-K.alpha./40 kV/100 mA, Scan speed; 4.degree./min.
(Analysis of Raw Materials, Products, and by-Products in the
Production of an .alpha.,.beta.-Unsaturated Carboxylic Acid)
[0111] The analysis of raw materials, products, and by-products in
the production of an .alpha.,.beta.-unsaturated carboxylic acid was
carried out using gas chromatography. Now, conversion of an olefin,
selectivity to an .alpha.,.beta.-unsaturated aldehyde to be
produced, selectivity to an .alpha.,.beta.-unsaturated carboxylic
acid to be produced and selectivity to carbon dioxide to be
produced as a by-product are defined in the following.
Conversion of an olefin (%)=(B/A).times.100 Selectivity to an
.alpha.,.beta.-unsaturated aldehyde (%)=(C/B).times.100 Selectivity
to an .alpha.,.beta.-unsaturated carboxylic acid
(%)=(D/B).times.100 Selectivity to carbon dioxide
(%)=(E/B).times.100
[0112] In these formulae, A represents number of moles of an olefin
supplied, B represents number of moles of an olefin reacted, C
represents number of moles of an .alpha.,.beta.-unsaturated
aldehyde produced, D represents number of moles of an
.alpha.,.beta.-unsaturated carboxylic acid produced, and E
represents (number of moles of carbon dioxide produced as a
by-product)/(number of carbon atoms in an olefin which is a raw
material (4 in the case of isobutylene)).
Example 1
Preparation of Catalyst
[0113] To an aqueous solution obtained by dissolving 0.26 part of
tartaric acid in 2.3 parts of pure water, 0.05 part of antimony
oxide was dispersed and the resultant mixture was stirred for 30
minutes at 60.degree. C. To the resultant homogeneous solution, 3.3
parts of palladium nitrate nitric acid solution (manufactured by
Tanaka Kikinzoku International K.K., palladium element content:
22.65% by mass) was added, and to the resultant aqueous solution,
pure water was further added to obtain, in all, 10.2 parts of the
resultant solution. This solution was added to 15.0 parts of a
particle silica carrier (specific surface area of 450 m.sup.2/g,
pore volume of 0.68 cc/g, median diameter of 53.58 .mu.m) little by
little and the resultant mixture was shaken while these operations
were repeated until the whole amount of the solution was added. The
carrier on which the solution was impregnated with such a
pore-filling method as described above was held at 100.degree. C.
in air for 3 hours, and calcined at 450.degree. C. in air for 3
hours to obtain a silica carrier on which palladium element and
antimony element were supported.
[0114] The silica carrier thus obtained was added to 40.0 parts of
37% by mass formaldehyde aqueous solution. Then a reduction
treatment was carried out by heating the system to 70.degree. C.
and keeping it at 70.degree. C. for 2 hours while stirring. Then
the system was filtrated under reduced pressure and filtrated while
washed with 1,000 parts of hot water. Thereafter, the resultant
system was dried at 100.degree. C. for 2 hours under nitrogen flow
to obtain a supported palladium-containing catalyst in which
reduced palladium element and reduced antimony element were
supported on the silica carrier. The Sb/Pd in the catalyst was
0.05. The loading ratio of palladium element was 5.0% by mass and
the loading ratio of antimony element was 0.26% by mass in this
catalyst. Here, a loading ratio means a ratio of a mass of each
element to a mass of a carrier in a catalyst. In the XRD
measurement of this catalyst, a peak was detected at around
2.theta. of 39.880 degrees.
[0115] In Examples 1 to 4 and Comparative Example 2, masses of
palladium element, antimony element, and tellurium element, which
were used in calculating Sb/Pd, Te/Pd, and a loading ratio of each
element, were calculated from a palladium element content and a
compounding amount of the raw material of palladium to be used, an
antimony element content and a compounding amount of the raw
material of antimony to be used, and a tellurium element content
and a compounding amount of the raw material of tellurium to be
used. The mass of the carrier in the catalyst was quantitatively
determined as follows. At first, the catalyst was introduced into a
platinum crucible and fused after sodium carbonate was added. Then,
to the resultant mixture, distilled water was added to make a
homogeneous solution and a quantitative determination of Si atom in
the sample solution was carried out with ICP atomic emission
spectrometry.
(Evaluation of Reaction)
[0116] Into an autoclave, 10.5 parts of the catalyst obtained by
the above-mentioned method and 75 parts of 75% by mass t-butanol
aqueous solution as a reaction solvent were introduced and the
autoclave was shut tight. Subsequently, 2.0 parts of isobutylene
was introduced into it, and the system was stirred (number of
revolutions: 1,000 rpm) and heated to 90.degree. C. After the
heating was finished, nitrogen was introduced into the autoclave to
the internal pressure of 2.4 MPa and then air was introduced into
it to the internal pressure of 4.8 MPa and the reaction was
started. Each time when the internal pressure dropped by 0.15 MPa
the internal pressure: 4.65 MPa), oxygen was introduced into it by
0.15 MPa to adjust the internal pressure to 4.8 MPa (hereinafter,
expressed also as "oxygen introduction operation"), and this
operation was repeated 4 times during the reaction. The time taken
from the start of the reaction to the first oxygen introduction
operation was 4 minutes. After the fourth introduction of oxygen,
when the internal pressure dropped to 4.65 MPa, the reaction was
finished.
[0117] After the reaction was finished, the inside materials of the
autoclave were cooled by putting the autoclave into an ice bath. A
gas-sampling bag was attached to the gas outlet of the autoclave
and the gas outlet was opened and the emerging gas was collected
while the internal pressure of the reactor was released. The
reaction liquid containing catalyst was taken out from the
autoclave and the catalyst was separated by membrane filter and the
reaction liquid was recovered. The recovered reaction liquid and
the sampled gas were analyzed with gas chromatography and
conversion and selectivity were calculated. The results are shown
in Table 1.
Example 2
Preparation of Catalyst
Step 1:
[0118] To 3.3 parts of palladium nitrate nitric acid solution
(manufactured by Tanaka Kikinzoku International K.K., palladium
element content: 22.65% by mass), pure water was further added to
obtain, in all, 10.2 parts of the resultant aqueous solution. This
aqueous solution was added to 15.0 parts of a particle silica
carrier, which is the same as that used in Example 1, little by
little and the resultant mixture was shaken while these operations
were repeated until the whole amount of the solution was added. The
carrier on which the solution was impregnated by such a
pore-filling method as described above was calcined at 450.degree.
C. in air for 3 hours to obtain a silica carrier on which palladium
oxide was supported.
Step 2:
[0119] To 2.3 parts of pure water in which 0.52 part of tartaric
acid was dissolved, 0.10 part of antimony oxide was dispersed and
the resultant mixture was stirred for 30 minutes at 60.degree. C.
The homogeneous solution thus obtained was added to the silica
carrier obtained in the step 1, on which palladium oxide was
supported, little by little and the resultant mixture was shaken
while these operations were repeated until the whole amount of the
solution was added. A silica carrier containing palladium element
and antimony element was obtained by impregnating the solution by
such a pore-filling method as described above.
[0120] The silica carrier thus obtained was added to 40.0 parts of
37% by mass formaldehyde aqueous solution. Then a reduction
treatment was carried out by heating the system to 70.degree. C.
and keeping it at 70.degree. C. for 2 hours while stirring. Then
the system was filtrated under reduced pressure and filtrated while
washed with 1,000 parts of hot water. Thereafter, the resultant
system was dried at 100 C for 2 hours under nitrogen flow to obtain
a supported palladium-containing catalyst in which reduced
palladium element and reduced antimony element were supported on
the silica carrier. The Sb/Pd in the catalyst was 0.10. The loading
ratio of palladium element was 5.0% by mass and the loading ratio
of antimony element was 0.53% by mass in this catalyst. In the XRD
measurement of this catalyst, a peak was detected at around
2.theta. of 39.700 degrees.
(Evaluation of Reaction)
[0121] The same procedure of evaluation of reaction as in Example 1
was carried out except that 10.6 parts of the catalyst obtained by
the above-mentioned method was used. The time taken from the start
of the reaction to the first oxygen introduction operation was 3
minutes. The results are shown in Table 1.
Example 3
Preparation of Catalyst
[0122] The same procedure as in Example 1 was carried out except
that the amount of antimony oxide used was changed to 0.15 part and
the amount of tartaric acid used was changed to 0.78 part and a
palladium-containing catalyst was obtained. The Sb/Pd in the
catalyst was 0.15. The loading ratio of palladium element was 5.0%
by mass and the loading ratio of antimony element was 0.79% by mass
in this catalyst. In the XRD measurement of this catalyst, a peak
was detected at around 2.theta. of 39.600 degrees.
(Evaluation of Reaction)
[0123] The same procedure of evaluation of reaction as in Example 1
was carried out using the catalyst obtained by the above-mentioned
method. The time taken from the start of the reaction to the first
oxygen introduction operation was 6 minutes. The results are shown
in Table 1.
Example 4
Preparation of Catalyst
[0124] To 2.3 parts of pure water in which 0.30 part of tartaric
acid was dissolved, 0.07 part of antimony oxide was dispersed and
the resultant mixture was stirred for 30 minutes at 60.degree. C.
To the resultant homogeneous solution, 4.5 parts of palladium
nitrate nitric acid solution (manufactured by Tanaka Kikinzoku
Kogyo K.K., palladium element content: 22.65% by mass) was added.
The resultant aqueous solution was added to 5.0 parts of a particle
silica carrier (specific surface area of 450 m.sup.2/g, pore volume
of 0.68 cc/g, median diameter of 53.58 .mu.m) little by little and
the resultant mixture was shaken while these operations were
repeated until the whole amount of the solution was added. The
carrier on which the solution was impregnated by such a
pore-filling method as described above was calcined at 450.degree.
C. in air for 3 hours to obtain a silica carrier on which palladium
element and antimony element were supported.
[0125] The silica carrier thus obtained was added to 70 parts of
37% by mass formaldehyde aqueous solution. Then a reduction
treatment was carried out by heating the system to 70.degree. C.
and keeping it at 70.degree. C. for 2 hours while stirring. Then
the system was filtrated under reduced pressure and filtrated while
washed with 1,000 parts of hot water. After the washing, a silica
carrier on which palladium element and antimony element subjected
to reducing treatment were supported was obtained. Further, this
silica carrier was dispersed in 50.0 parts of pure water, and a
telluric acid aqueous solution obtained by dissolving 0.06 part of
telluric acid in 5.0 parts of pure water was dropped to this
dispersed solution thus obtained. Then a treatment was carried out
by heating the system to 70.degree. C. and keeping it at 70.degree.
C. for 2 hours while stirring. Then the system was filtrated under
reduced pressure and filtrated while washed with 1,000 parts of hot
water. Thereafter, the resultant system was dried at 100.degree. C.
for 2 hours under nitrogen flow to obtain a supported
palladium-containing catalyst in which reduced palladium element,
reduced antimony element, and reduced tellurium element were
supported on the silica carrier. The Sb/Pd was 0.05 and Te/Pd was
0.05 in the catalyst. The loading ratio of palladium element was
20.0% by mass, the loading ratio of antimony element was 1.14% by
mass, and the loading ratio of tellurium element was 1.20% by mass
in this catalyst. In the XRD measurement of this catalyst, a peak
was detected at around 2.theta. of 39.870 degrees.
(Evaluation of Reaction)
[0126] Into an autoclave, 3.0 parts of the catalyst obtained by the
above-mentioned method and 75 parts of 75% by mass t-butanol
aqueous solution as a reaction solvent were introduced and the
autoclave was shut tight. Subsequently, 2.0 parts of isobutylene
was introduced into it, and the system was stirred (number of
revolutions: 1,000 rpm) and heated to 90.degree. C. After the
heating was finished, nitrogen was introduced into the autoclave to
the internal pressure of 2.4 MPa and then air was introduced into
it to the internal pressure of 4.8 MPa and the reaction was
started. Each time when the internal pressure dropped by 0.10 MPa
(the internal pressure: 4.70 MPa), oxygen was introduced into it by
0.10 MPa to adjust the internal pressure to 4.8 MPa (hereinafter,
also expressed as "oxygen introduction operation"), and this
operation was repeated 8 times during the reaction. The time taken
from the start of the reaction to the first oxygen introduction
operation was 2 minutes. After the eighth introduction of oxygen,
when the internal pressure dropped to 4.70 MPa, the reaction was
finished.
[0127] After the reaction was finished, the inside materials of the
autoclave were cooled by putting the autoclave into an ice bath. A
gas-sampling bag was attached to the gas outlet of the autoclave
and the gas outlet was opened and the emerging gas was collected
while the internal pressure of the reactor was released. The
reaction liquid containing catalyst was taken out from the
autoclave and the catalyst was separated by membrane filter and the
reaction liquid was recovered. The recovered reaction liquid and
the sampled gas were analyzed with gas chromatography and
conversion and selectivity were calculated. The results are shown
in Table 1.
Comparative Example 1
Preparation of Catalyst
[0128] To 2.16 parts of palladium nitrate solution (manufactured by
N. E. Chemcat Corporation: nitric acid aqueous acidic solution
containing 23.2% by mass palladium nitrate), pure water was further
added to obtain, in all, 6.8 parts of the resultant solution. This
solution was added to 10.0 parts of a particle silica carrier
(specific surface area of 450 m.sup.2/g, pore volume of 0.68 cc/g)
little by little and the resultant mixture was shaken while these
operations were repeated until the whole amount of the solution was
added. The solution was thus impregnated to the carrier with such a
pore-filling method as described above, and evaporation of the
resultant carrier was carried out. Subsequently, calcination of the
resultant carrier was carried out at 450.degree. C. in air for 3
hours. The catalyst precursor thus obtained was added to 20 parts
of 37% by mass formaldehyde aqueous solution. Then the system was
heated to 70.degree. C., kept at 70.degree. C. for 2 hours while
stirred, filtrated under reduced pressure and filtrated while
washed with 1,000 parts of hot water to obtain a silica supported
palladium-containing catalyst. The loading ratio of palladium
element was 5.0% by mass in this catalyst. Here, a loading ratio
means a ratio of a mass of each element to a mass of a carrier in a
catalyst. In the XRD measurement of this catalyst, a peak was
detected at 2.theta. of 39.48 degrees and it was confirmed that the
catalyst contained palladium element which composed a metal.
[0129] In Examples 5 to 8, Comparative Example 1, and Comparative
Examples 3 to 5, Te/Pd, Bi/Pd, and a loading ratio of each element
were calculated from masses and atomic weights of palladium
element, tellurium element, and bismuth element contained in the
catalyst after preparation, and a mass of a carrier. The masses of
palladium element, tellurium element, and bismuth element contained
in the catalyst were measured by the following method.
Preparation of a Treatment Liquid:
[0130] Into a Teflon (registered trademark) decomposition tube, 1
part of the catalyst, 50 parts of 62% by mass nitric acid aqueous
solution, and 50 parts of 48% by mass hydrofluoric acid aqueous
solution were introduced and a dissolving treatment was carried out
using a microwave digestion device (MARS5 (trade name) manufactured
by CEM Corporation).
[0131] Each mass of palladium element, tellurium element, and
bismuth element contained in the homogeneous solution thus obtained
was determined quantitatively with ICP atomic emission spectrometer
(IRIS-Advantage (trade name) manufactured by Thermo Elemental Co.,
Ltd.), and each mass was estimated as the mass of each element in
the catalyst. The mass of the carrier in the catalyst was
quantitatively determined as follows. At first, the catalyst was
introduced into a platinum crucible and fused after sodium
carbonate was added. Then, to the resultant mixture, distilled
water was added to make a homogeneous solution and a quantitative
determination of Si atom in the sample solution was carried out
with ICP atomic emission spectrometry.
(Evaluation of Reaction)
[0132] The total amount of the catalyst (0.5 part as palladium
element) obtained by the above-mentioned method and 75 parts of 75%
by mass t-butanol aqueous solution as a reaction solvent were
introduced into an autoclave and the autoclave was shut tight.
Subsequently, 2.0 parts of isobutylene was introduced into it, and
the system was stirred (number of revolutions: 1,000 rpm) and
heated to 90.degree. C. After the heating was finished, nitrogen
was introduced into the autoclave to the internal pressure of 2.4
MPa and then compressed air was introduced into it to the internal
pressure of 4.8 MPa. When the internal pressure dropped by 0.15 MPa
(the internal pressure: 4.65 MPa), oxygen was introduced into it by
0.15 MPa, and this operation was repeated during the reaction. The
reaction was finished when the reaction time was 60 minutes.
[0133] After the reaction was finished, the inside of the autoclave
was cooled by an ice bath. A gas-sampling bag was attached to the
gas outlet of the autoclave and the gas outlet was opened and the
emerging gas was collected while the internal pressure of the
reactor was released. The reaction liquid containing catalyst was
taken out from the autoclave and the catalyst was separated by
membrane filter and the reaction liquid was recovered. The
recovered reaction liquid and the sampled gas were analyzed with
gas chromatography and conversion and selectivity were calculated.
The results are shown in Table 1 and Table 2.
Comparative Example 2
Preparation of Catalyst
[0134] The same procedure as in Example 1 was carried out except
that the amount of antimony oxide used was changed to 0.31 part and
the amount of tartaric acid used was changed to 1.55 part and a
palladium-containing catalyst was obtained. The Sb/Pd in the
catalyst was 0.30. The loading ratio of palladium element was 5.0%
by mass and the loading ratio of antimony element was 1.62% by mass
in this catalyst. In the XRD measurement of this catalyst, a peak
was detected at around 2.theta. of 39.500 degrees.
(Evaluation of Reaction)
[0135] The same procedure of evaluation of reaction as in Example 1
was carried out except that 10.7 parts of the catalyst obtained by
the above-mentioned method was used. However, after the reaction
was started, it took a longer time for the internal pressure to
drop to reach 4.65 MPa, to be more precise, the time taken from the
start of the reaction to the first oxygen introduction operation
was 45 minutes. Consequently, the reaction was finished when 60
minutes had passed from the start of the reaction (oxygen
introduction operation being only once), because it was understood
that the catalyst had a lower activity than that of Example 1. The
results are shown in Table 1.
TABLE-US-00001 TABLE 1 Conversion Selectivity Selectivity Reaction
of to to Sb/Pd Te/Pd time isobutylene methacrolein methacrylic acid
(molar ratio) (molar ratio) (min) (%) (%) (%) Ex. 1 0.05 0 74 67.0
17.3 43.3 Ex. 2 0.1 0 90 56.5 14.8 57.4 Ex. 3 0.15 0 120 60.5 18.8
50.1 Ex. 4 0.05 0.05 50 81.4 19.0 47.4 Comp. 0 0 60 52.8 15.7 33.8
Ex. 1 Comp. 0.3 0 60 2.2 12.7 1.7 Ex. 2
[0136] As illustrated above, an .alpha.,.beta.-unsaturated
carboxylic acid can be produced in higher selectivity by using the
palladium-containing catalyst of the present invention.
Example 5
Preparation of Catalyst
[0137] To 0.0228 part of bismuth nitrate pentahydrate, 10 times the
mass of bismuth nitrate pentahydrate of 62% by mass nitric acid
aqueous solution was added to make a homogeneous solution. To this
solution, 0.151 part of telluric acid and 10 times the mass of
telluric acid of distilled water were added to make a homogeneous
solution. To this solution, 2.16 parts of palladium nitrate
solution (manufactured by N. E. Chemcat Corporation: nitric acid
aqueous acidic solution containing 23.2% by mass palladium nitrate)
was added and pure water was further added to obtain, in all, 6.8
parts of the resultant solution. This solution was added to 10.0
parts of a particle silica carrier (specific surface area of 450
m.sup.2/g, pore volume of 0.68 cc/g) little by little and the
resultant mixture was shaken while these operations were repeated
until the whole amount of the solution was added. The solution was
thus impregnated to the carrier by such a pore-filling method as
described above, and evaporation of the resultant carrier was
carried out. Subsequently, calcination of the resultant carrier was
carried out at 450.degree. C. in air for 3 hours. The catalyst
precursor thus obtained was added to 20 parts of 37% by mass
formaldehyde aqueous solution. Then the system was heated to
70.degree. C., kept at 70.degree. C. for 2 hours while stirred,
filtrated under reduced pressure and filtrated while washed with
1,000 parts of hot water to obtain a silica supported
palladium-containing catalyst. The Te/Pd was 0.14 and Bi/Pd was
0.01 in the catalyst. The loading ratio of palladium element was 5%
by mass, the loading ratio of tellurium element was 0.84% by mass,
and the loading ratio of bismuth element was 0.1% by mass in this
catalyst. In the XRD measurement of this catalyst, a peak was
detected at 2.theta. of 39.66 degrees and it was confirmed that the
catalyst contained palladium element which composed a metal.
(Evaluation of Reaction)
[0138] The total amount of the catalyst (0.5 part as palladium
element) obtained by the above-mentioned method and 75 parts of 75%
by mass t-butanol aqueous solution as a reaction solvent were
introduced into an autoclave and the autoclave was shut tight.
Subsequently, 2.0 parts of isobutylene was introduced into it, and
the system was stirred (number of revolutions: 1,000 rpm) and
heated to 90.degree. C. After the heating was finished, nitrogen
was introduced into the autoclave to the internal pressure of 2.4
MPa and then compressed air was introduced into it to the internal
pressure of 4.8 MPa. When the internal pressure dropped by 0.15 MPa
(the internal pressure: 4.65 MPa), oxygen was introduced into it by
0.15 MPa, and this operation was repeated during the reaction. The
reaction was finished when the reaction time was 60 minutes.
[0139] After the reaction was finished, the inside of the autoclave
was cooled by an ice bath. A gas-sampling bag was attached to the
gas outlet of the autoclave and the gas outlet was opened and the
emerging gas was collected while the internal pressure of the
reactor was released. The reaction liquid containing catalyst was
taken out from the autoclave and the catalyst was separated by
membrane filter and the reaction liquid was recovered. The
recovered reaction liquid and the sampled gas were analyzed with
gas chromatography and conversion and selectivity were calculated.
The results are shown in Table 2.
Example 6
Preparation of Catalyst
[0140] The same procedure as in Example 5 was carried out except
that the amount of bismuth nitrate pentahydrate used was changed to
0.0570 part and the amount of telluric acid used was changed to
0.135 part and a palladium-containing catalyst was obtained. The
Te/Pd was 0.125 and Bi/Pd was 0.025 in the catalyst. The loading
ratio of palladium element was 5% by mass, the loading ratio of
tellurium element was 0.75% by mass, and the loading ratio of
bismuth element was 0.25% by mass in this catalyst. In the XRD
measurement of this catalyst, a peak was detected at 2.theta. of
39.50 degrees and it was confirmed that the catalyst contained
palladium element which composed a metal.
(Evaluation of Reaction)
[0141] The same procedure of evaluation of reaction as in Example 5
was carried out using the catalyst obtained by the above-mentioned
method. The results are shown in Table 2.
Example 7
Preparation of Catalyst
[0142] The same procedure as in Example 5 was carried out except
that the amount of bismuth nitrate pentahydrate used was changed to
0.0912 part and the amount of telluric acid used was changed to
0.119 part and a palladium-containing catalyst was obtained. The
Te/Pd was 0.11 and Bi/Pd was 0.04 in the catalyst. The loading
ratio of palladium element was 5% by mass, the loading ratio of
tellurium element was 0.66% by mass, and the loading ratio of
bismuth element was 0.39% by mass in this catalyst. In the XRD
measurement of this catalyst, a peak was detected at 2.theta. of
39.54 degrees and it was confirmed that the catalyst contained
palladium element which composed a metal.
(Evaluation of Reaction)
[0143] The same procedure of evaluation of reaction as in Example 5
was carried out using the catalyst obtained by the above-mentioned
method. The results are shown in Table 2.
Example 8
Preparation of Catalyst
[0144] The same procedure as in Example 5 was carried out except
that the amount of bismuth nitrate pentahydrate used was changed to
0.114 part and the amount of telluric acid used was changed to
0.108 part and a palladium-containing catalyst was obtained. The
Te/Pd was 0.10 and Bi/Pd was 0.05 in the catalyst. The loading
ratio of palladium element was 5% by mass, the loading ratio of
tellurium element was 0.6% by mass, and the loading ratio of
bismuth element was 0.49% by mass in this catalyst. In the XRD
measurement of this catalyst, a peak was detected at 2.theta. of
39.48 degrees and it was confirmed that the catalyst contained
palladium element which composed a metal.
(Evaluation of Reaction)
[0145] The same procedure of evaluation of reaction as in Example 5
was carried out using the catalyst obtained by the above-mentioned
method. The results are shown in Table 2.
Comparative Example 3
Preparation of Catalyst
[0146] The same procedure as in Example 5 was carried out except
that the amount of bismuth nitrate pentahydrate used was changed to
0.114 part and telluric acid was not used, and a
palladium-containing catalyst was obtained. The Bi/Pd in the
catalyst was 0.05. The loading ratio of palladium element was 5% by
mass and the loading ratio of bismuth element was 0.49% by mass in
this catalyst. In the XRD measurement of this catalyst, a peak was
detected at 2.theta. of 39.70 degrees and it was confirmed that the
catalyst contained palladium element which composed a metal.
(Evaluation of Reaction)
[0147] The same procedure of evaluation of reaction as in Example 5
was carried out using the catalyst obtained by the above-mentioned
method. The results are shown in Table 2.
Comparative Example 4
Preparation of Catalyst
[0148] The same procedure as in Example 5 was carried out except
that, to 0.752 part of bismuth nitrate pentahydrate, 4 times the
mass of bismuth nitrate pentahydrate of 62% by mass nitric acid
aqueous solution was added to make a homogeneous solution, and
further, telluric acid was not used, and a palladium-containing
catalyst was obtained. The Bi/Pd in the catalyst was 0.33. The
loading ratio of palladium element was 5% by mass and the loading
ratio of bismuth element was 3.24% by mass in this catalyst. In the
XRD measurement of this catalyst, a peak was detected at 2.theta.
of 39.00 degrees and it was confirmed that the catalyst contained
palladium element which composed a metal.
(Evaluation of Reaction)
[0149] The same procedure of evaluation of reaction as in Example 5
was carried out using the catalyst obtained by the above-mentioned
method. The results are shown in Table 2.
Comparative Example 5
Preparation of Catalyst
[0150] The same procedure as in Example 5 was carried out except
that bismuth nitrate pentahydrate was not used and the amount of
telluric acid used was changed to 0.162 part, and a
palladium-containing catalyst was obtained. The Te/Pd in the
catalyst was 0.15. The loading ratio of palladium element was 5% by
mass and the loading ratio of tellurium element was 0.9% by mass in
this catalyst. In the XRD measurement of this catalyst, a peak was
detected at 2.theta. of 39.20 degrees and it was confirmed that the
catalyst contained palladium element which composed a metal.
(Evaluation of Reaction)
[0151] The same procedure of evaluation of reaction as in Example 5
was carried out using the catalyst obtained by the above-mentioned
method. The results are shown in Table 2.
TABLE-US-00002 TABLE 2 Conversion Selectivity Selectivity
Selectivity of to to to Te/Pd Bi/Pd isobutylene methacrolein
methacrylic acid carbon dioxide (molar ratio) (molar ratio) (%) (%)
(%) (%) Ex. 5 0.14 0.01 68.0 21.6 46.1 2.8 Ex. 6 0.125 0.025 77.1
19.8 51.8 2.4 Ex. 7 0.11 0.04 68.9 29.2 45.3 2.9 Ex. 8 0.10 0.05
72.1 25.0 46.3 3.8 Comp. 0 0 52.8 15.7 33.8 6.0 Ex. 1 Comp. 0 0.05
56.8 21.5 39.3 4.6 Ex. 3 Comp. 0 0.33 20.1 17.2 0.6 4.3 Ex. 4 Comp.
0.15 0 67.8 17.3 44.5 5.5 Ex. 5
[0152] As illustrated above, an .alpha.,.beta.-unsaturated
carboxylic acid can be produced in higher selectivity and a small
amount of carbon dioxide was formed as a by-product by using the
palladium-containing catalyst of the present invention.
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