U.S. patent application number 10/372262 was filed with the patent office on 2003-08-14 for complex oxide catalyst and process for preparation of acrylic acid.
Invention is credited to Nakamura, Daisuke, Tanimoto, Michio, Yunoki, Hiromi.
Application Number | 20030153786 10/372262 |
Document ID | / |
Family ID | 18401274 |
Filed Date | 2003-08-14 |
United States Patent
Application |
20030153786 |
Kind Code |
A1 |
Tanimoto, Michio ; et
al. |
August 14, 2003 |
Complex oxide catalyst and process for preparation of acrylic
acid
Abstract
A catalyst which is a complex oxide catalyst represented by the
following general formula (1):
Mo.sub.aV.sub.bW.sub.cCu.sub.dA.sub.eB.sub.fC.sub.gD.sub.hE.sub.iO.sub.x
(1) (in which Mo is molybdenum; V is vanadium, W is tungsten, Cu is
copper, A is at least an element selected from antimony, niobium
and tin; B is at least an element selected from alkaline earth
metals; C is at least an element selected from silicon, aluminum,
titanium and zirconium; D is at least an element selected from
phosphorus, tellurium, cerium, lead, arsenic and zinc; E is at
least an element selected from Group IA and Group IIIb elements of
the periodic table, boron, iron, bismuth, cobalt, nickel and
manganese; and O is oxygen; a, b, c, d, e, f, g, h, i and x denote
the atomic ratios of Mo, V, W, Cu, A, B, C, D, E and O,
respectively; and where a=12, 2.ltoreq.b.ltoreq.15,
0.ltoreq.c.ltoreq.10, 0<d.ltoreq.6, 0.ltoreq.e.ltoreq.6,
0<f.ltoreq.10, 0<g.ltoreq.10, 0.ltoreq.h.ltoreq.5,
0.ltoreq.i.ltoreq.5, and x is a numerical value determined by the
extents of oxidation of the other elements) which is characterized
by being formed of a complex oxide which is prepared by using, as
at least a part of the supply sources of components B and C, a
compound containing both of the components B and C is provided. The
catalyst is useful for vapor phase catalytic oxidation, in
particular, is suitable as a catalyst for preparing acrylic acid by
vapor phase catalytic oxidation of acrolein.
Inventors: |
Tanimoto, Michio;
(Himeji-shi, JP) ; Nakamura, Daisuke; (Himeji-shi,
JP) ; Yunoki, Hiromi; (Himeji-shi, JP) |
Correspondence
Address: |
SHERMAN & SHALLOWAY
413 North Washington Street
Alexandria
VA
22314
US
|
Family ID: |
18401274 |
Appl. No.: |
10/372262 |
Filed: |
February 25, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10372262 |
Feb 25, 2003 |
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09729433 |
Dec 5, 2000 |
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6545177 |
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Current U.S.
Class: |
562/535 ;
502/254; 502/311 |
Current CPC
Class: |
C07C 51/252 20130101;
B01J 23/8885 20130101; B01J 23/002 20130101; B01J 23/8877 20130101;
B01J 2523/00 20130101; C07C 51/252 20130101; C07C 57/04 20130101;
B01J 2523/00 20130101; B01J 2523/17 20130101; B01J 2523/22
20130101; B01J 2523/31 20130101; B01J 2523/41 20130101; B01J
2523/53 20130101; B01J 2523/55 20130101; B01J 2523/68 20130101;
B01J 2523/69 20130101; B01J 2523/00 20130101; B01J 2523/17
20130101; B01J 2523/24 20130101; B01J 2523/31 20130101; B01J
2523/41 20130101; B01J 2523/53 20130101; B01J 2523/55 20130101;
B01J 2523/68 20130101; B01J 2523/69 20130101; B01J 2523/845
20130101; B01J 2523/00 20130101; B01J 2523/12 20130101; B01J
2523/17 20130101; B01J 2523/23 20130101; B01J 2523/25 20130101;
B01J 2523/31 20130101; B01J 2523/41 20130101; B01J 2523/55
20130101; B01J 2523/68 20130101; B01J 2523/69 20130101; B01J
2523/00 20130101; B01J 2523/13 20130101; B01J 2523/17 20130101;
B01J 2523/22 20130101; B01J 2523/31 20130101; B01J 2523/41
20130101; B01J 2523/55 20130101; B01J 2523/68 20130101; B01J
2523/69 20130101; B01J 2523/842 20130101; B01J 2523/00 20130101;
B01J 2523/17 20130101; B01J 2523/22 20130101; B01J 2523/41
20130101; B01J 2523/47 20130101; B01J 2523/53 20130101; B01J
2523/55 20130101; B01J 2523/68 20130101; B01J 2523/69 20130101 |
Class at
Publication: |
562/535 ;
502/254; 502/311 |
International
Class: |
C07C 051/16; C07C
051/235; B01J 021/08; B01J 021/12; B01J 021/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 8, 1999 |
JP |
349,067/99 |
Claims
1. A catalyst which is a complex oxide catalyst represented by the
following general formula (1):
Mo.sub.aV.sub.bW.sub.cCu.sub.dA.sub.eB.sub-
.fC.sub.gD.sub.hE.sub.iO.sub.x (1) (in which Mo is molybdenum; V is
vanadium, W is tungsten, Cu is copper, A is at least an element
selected from antimony, niobium and tin; B is at least an element
selected from alkaline earth metals; C is at least an element
selected from silicon, aluminum, titanium and zirconium; D is at
least an element selected from phosphorus, tellurium, cerium, lead,
arsenic and zinc; E is at least an element selected from Group IA
and Group IIIb elements of the periodic table, boron, iron,
bismuth, cobalt, nickel and manganese; and O is oxygen; a, b, c, d,
e, f, g, h, i and x denote the atomic ratios of Mo, V, W, Cu, A, B,
C, D, E and O, respectively; and where a=12, 2b.ltoreq.15,
0.ltoreq.c.ltoreq.10, 0<d.ltoreq.6, 0.ltoreq.e.ltoreq.6,
0.ltoreq.f.ltoreq.10, 0.ltoreq.g.ltoreq.10, 0.ltoreq.h.ltoreq.5,
0i.ltoreq.5, and x is a numerical value determined by the extents
of oxidation of the other elements) which is characterized by being
formed of a complex oxide which is prepared by using, as at least a
part of the supply sources of components B and C, a compound
containing both of the components B and C.
2. A complex oxide catalyst as described in claim 1, in which the
component B is at least an element selected from magnesium,
calcium, strontium and barium.
3. A complex oxide catalyst as described in claim 1 or 2, in which
the component C is at least an element selected from silicon and
aluminum.
4. A complex oxide catalyst as described in any one of claims 1-3,
in which the compound containing both of the components B and C is
heat-treated at 500-2000.degree. C.
5. A process for preparing acrylic acid through oxidation of
acrolein at vapor phase with molecular oxygen or a molecular
oxygen-containing gas in the presence of a catalyst, which is
characterized in that the complex oxide catalyst of claim 1 is used
as the catalyst.
Description
FIELD OF INDUSTRIAL UTILIZATION
[0001] This invention relates to complex oxide catalysts and
production process of acrylic acid. More particularly, the
invention relates to complex oxide catalysts suitable for use in
producing acrylic acid from acrolein by vapor-phase catalytic
oxidation reaction, and to a producing process of acrylic acid from
acrolein using said catalysts.
PRIOR ART
[0002] A large number of improved catalysts for preparing acrylic
acid through vapor phase catalytic oxidation reaction of acrolein
have been proposed. For example, Japanese Patent Publication No.
12129/69 described a catalyst formed of molybdenum, vanadium and
tungsten; Publication No. 11371/74, that formed of molybdenum,
vanadium, copper, tungsten and chromium; Publication No. 25914/75,
that formed of molybdenum and vanadium; and Laid-open (Kokai)
Patent Application, Kokai No. 85091/77, that formed of molybdenum,
vanadium, copper and at least one element of antimony and
germanium.
[0003] However, these conventional catalysts are not fully
satisfactory for industrial working, because of such defects that
the yield of the object product, i.e., acrylic acid, is
insufficient and deterioration rate in activity is high, leading to
short catalyst life. Therefore, development of catalysts which
excel in stability and enable acrylic acid production at high yield
over prolonged periods has been in demand.
[0004] The applicant has disclosed the catalysts containing
molybdenum, vanadium and alkaline earth metals in Laid-open (Kokai)
Patent Application, Kokai No. 117419/74, which catalysts, however,
are still open to improvements in respect of acrylic acid yield and
catalyst life.
PROBLEM TO BE SOLVED BY THE INVENTION
[0005] Accordingly, one of the objects of the present invention is
to provide complex oxide catalysts, in particular, those which are
suitable for producing acrylic acid through vapor phase catalytic
oxidation of acrolein.
[0006] Another object of the present invention is to provide a
process for preparing acrylic acid at high yield over prolonged
periods, by oxidizing acrolein in the presence of catalyst at vapor
phase with molecular oxygen or a molecular oxygen-containing
gas.
MEANS TO SOLVE THE PROBLEM
[0007] We have discovered that the desired catalysts excelling in
activity, selectivity and also catalyst life and which exhibit
stable performance over prolonged periods can be obtained in the
occasion of preparing a complex oxide catalysts expressed by the
following general formula (1):
Mo.sub.aV.sub.bW.sub.cCu.sub.dA.sub.eB.sub.fC.sub.gD.sub.hE.sub.iO.sub.x
(1)
[0008] (in which the components and their ratios are as later
identified),
[0009] when a compound containing both components B and C is used
as at least a part of supply sources of components B and C; and
that the use of this catalyst enables production of acrylic acid
from acrolein at high yield over prolonged periods. Based on these
discoveries the present invention is completed.
[0010] Namely, the present invention relates to a complex oxide
catalyst which is expressed by the following general formula
(1):
Mo.sub.aV.sub.bW.sub.cCu.sub.dA.sub.eB.sub.fC.sub.gD.sub.hE.sub.iO.sub.x
(2)
[0011] (in which Mo is molybdenum; V is vanadium, W is tungsten, Cu
is copper, A is at least an element selected from antimony, niobium
and tin; B is at least an element selected from alkaline earth
metals; C is at least an element selected from silicon, aluminum,
titanium and zirconium; D is at least an element selected from
phosphorus, tellurium, cerium, lead, arsenic and zinc; E is at
least an element selected from Group IA and Group IIIb elements of
the periodic table, boron, iron, bismuth, cobalt, nickel and
manganese; and O is oxygen; a, b, c, d, e, f, g, h, i and x denote
the atomic ratios of Mo, V, W, Cu, A, B, C, D, E and O,
respectively; and where a=12, 2.ltoreq.b.ltoreq.15,
0.ltoreq.c.ltoreq.10, 0<d.ltoreq.6 (preferably
0.05.ltoreq.d.ltoreq.6), 0.ltoreq.e.ltoreq.6, 0<f.ltoreq.10
(preferably 0.01.ltoreq.f.ltoreq.10), 0.ltoreq.g.ltoreq.10
(preferably 0.01.ltoreq.g.ltoreq.10), 0.ltoreq.h.ltoreq.5,
0.ltoreq.i.ltoreq.5, and x is a numerical value determined by the
extents of oxidation of the other elements)
[0012] which is characterized in that a compound containing both of
the components B and C is used as at least a part of the supply
sources of components B and C at the time of the catalyst
preparation.
EMBODIMENTS OF THE INVENTION
[0013] Those complex oxide catalysts which are represented by the
general formula (1) are per se known as disclosed in said Kokai No.
117,419/74. In the complex oxide catalysts of the invention,
preferably antimony and tin are used as the component A; magnesium,
calcium, strontium and barium, as the component B; silicon and
aluminum, as the component C; phosphorus, tellurium and zinc; as
the component D; sodium, potassium, iron, cobalt, nickel and boron,
as the component E; respectively.
[0014] The characteristic feature of the invention lies in the use
of a compound containing both components B and C (which is
hereafter referred to as a B/C components--containing compound) as
at least a part of supply sources (starting compounds) of
components B and C in the occasion of preparing the complex oxide
catalysts of the present invention. The reason why the complex
oxide catalysts of excellent performance are obtained through such
a practice is not yet clear. At the present time we presume that
whereby improved stability of the component B contributes to the
better performance, while the scope of this invention should never
be restricted by this presumption.
[0015] The volume ratio of a B/C components--containing compound in
the supply sources of components B and C (i.e., total volume of the
starting material of component B and that of component C) is 0.5/1
to 1/1, preferably 0.8/1 to 1/1, in terms of the atomic ratio. In
particular, it is preferred to supply the total amount of the
component B in the catalyst from a B/C components--containing
compound.
[0016] As the supply sources for Mo, V, W, Cu, components A, D and
E; any compounds which contain the named individual elements and
which produce the corresponding oxides upon calcination can be
used.
[0017] As B/C components--containing compounds, any of marketed
compounds (preferably oxides) which contain both components B and C
can be used as they are. Examples of such marketed oxides include
barium aluminate (2BaO.Al.sub.2O.sub.3.5H.sub.2O), magnesium
silicate (Mg.sub.2Si.sub.3O.sub.8.5H.sub.2O), calcium silicate
(CaSiO.sub.3), barium titanate (BaTiO.sub.3), strontium titanate
(SrTiO.sub.3), calcium titanate (CaTiO.sub.3), calcium zirconate
(CaZrO.sub.3) and the like. Other than these commercial products,
oxides containing both components B and C can be prepared through,
for example, the following procedures: {circle over (1)} dissolve
or disperse a component B--containing compound and a component
C--containing compound in water, dewater and give such treatments
like drying, and thereafter calcine at prescribed temperatures,
preferably at 500-2000.degree. C.; {circle over (2)} thoroughly mix
a component B--containing oxide with a component C--containing
oxide and calcine the mixture at prescribed temperatures,
preferably at 500-2000.degree. C.; {circle over (3)} calcine a B/C
components--containing compound at prescribed temperatures,
preferably at 500-2000.degree. C.
[0018] Said B/C components--containing compounds are preferably
used in pulverized state to an average particle diameter of not
greater than 200 .mu.m, more advantageously not greater than 100
.mu.m, and most advantageously, not greater than 50 .mu.m.
[0019] Where either of the components B and C comprises more than
one element, it is sufficient for the B/C components--containing
compound to contain at least one of the elements as the component B
or C. The B/C components--containing compound may also contain a
component other than the components B and C, e.g., component E.
Obviously, such a compound is useful also as a supply source of the
component E.
[0020] The complex oxide catalysts of the invention can be prepared
by the methods generally practiced for preparing this kind of
complex oxide catalysts, except that a B/C components--containing
compound is used as at least a part of the supply sources of the
components B and C.
[0021] Shape of the complex oxide catalysts of the invention is not
critical. They may be molded into any optional forms such as ring,
sphere, column, tablet and the like, with an average diameter of
1-15 mm, preferably 3-10 mm. In preparing the catalysts, those well
known additives having the effect of improving the strength and
attrition resistance of catalysts, such as inorganic fibers, e.g.,
glass fiber or various whiskers may be added. Also for controlling
the catalyst properties with good reproducibility, additives
generally known as powder binder such as ammonium nitrate,
cellulose, starch, polyvinyl alcohol, stearic acid and the like may
be used.
[0022] While the complex oxide catalysts of the invention are each
useful by itself (as molded catalyst), they are preferably used in
the form supported on inert carriers such as alumina,
silica-alumina, silicon carbide, silicon nitride, titanium dioxide,
aluminium sponge and the like (as supported catalyst). In the
latter case, suitable supported ratio (%) of the complex oxide
expressed by the general formula (1) ([(weight of the complex
oxide)/(weight of the inert carrier+weight of the complex
oxide)].times.100) is 10-70%, preferably 15-50%.
[0023] Production of acrylic acid from acrolein according to the
present invention can be performed by any of known methods, except
that one of the so far described complex oxide catalysts should be
used as the catalyst. The apparatus and operating conditions in
carrying out the production are not critical. That is, as the
reactor, an ordinary fixed bed reactor, fuidable bed reactor or
moving bed reactor can be used, and the reaction can be carried out
under the conditions conventionally employed for production of
acrylic acid from acrolein through vapor phase catalytic oxidation
reaction. For example, a gaseous mixture of 1-15 volume % of
acrolein, 0.5-25 volume % of oxygen, 1-30 volume % of steam and
20-80 volume % of an inert gas like nitrogen, is contacted with a
complex oxide catalyst of the invention at temperatures ranging
from 200 to 400.degree. C., under a pressure of 0.1-1 MPa and at a
space velocity of 300-5,000 h.sup.-1 (STP) to produce acrylic
acid.
[0024] Besides such gaseous mixtures of acrolein, oxygen and inert
gas, acrolein-containing gaseous mixtures which are obtained
through direct oxidation of propylene may also be used as the
starting gas, if necessary after adding air or oxygen and steam.
Presence of such side products as acrylic acid, acetic acid, carbon
oxide and propane or unreacted propylene in the acrolein-containing
gaseous mixtures obtained upon direct oxidation of propylene is in
no way detrimental to the catalysts used in the process of the
invention.
EFFECT OF THE INVENTION
[0025] According to the invention, high-activity and
high-performance catalysts are obtainable with good
reproducibility. Moreover, because the complex oxide catalysts of
the invention maintain the high activity levels over prolonged
periods, acrylic acid can be stably produced at high yields over
prolonged periods according to the process of the invention.
EXAMPLES
[0026] Hereinafter the invention is explained more specifically
referring to working Examples, it being understood that the
Examples incur no restricting effect on the invention.
[0027] In the Examples, the acrolein conversion, acrylic acid
selectivity and acrylic acid yield were calculated according to the
following formulae:
[0028] acrolein conversion (%)=[(mol number of reacted
acrolein)/(mol number of fed acrolein)].times.100
[0029] acrylic acid selectivity (%)=[(mol number of formed acrylic
acid)/(mol number of reacted acrolein)].times.100
[0030] acrylic acid yield (%)=[(mol number of formed acrylic
acid)/(mol number of fed acrolein)].times.100
Example 1
[0031] [Preparation of Mg/Si--Al-Containing Compound]
[0032] Into 200 ml of pure water, 53 g of magnesium nitrate and 7.8
g of aluminium nitrate were dissolved under heating and stirring.
To the solution 93 g of 20% by weight silica sol was added, mixed
and evaporated to dryness under heating to provide a solid matter.
The solid was heat-treated at temperatures elevated stagewisely,
followed by 3 hours' calcination at 1,400.degree. C. The product
was pulverized to a powder (1) having an average particle diameter
of 30 .mu.m.
[0033] [Preparation of Catalyst]
[0034] Into 2,000 ml of pure water, 350 g of ammonium
paramolybdate, 106 g of ammonium metavanadate and 44.6 g of
ammonium paratungstate were dissolved under heating and stirring.
Separately, 87.8 g of cupric nitrate and 12 g of antimony trioxide
were added to 200 g of pure water under heat and stirring. Thus
obtained two liquids were mixed, 11.2 g of the powder (1) was added
to the liquid mixture and together poured into a porcelain
evaporator on hot water bath. Then, 1,200 ml of a silica-alumina
spherical carrier having an average particle diameter of 5 mm was
added, followed by evaporation to dryness under stirring to have
the catalyst deposited on the carrier. The carrier-supported
catalyst was calcined at 400.degree. C. for 6 hours to provide
Catalyst (1). The composition of metallic elements (excepting
oxygen, as in all of hereafter indicated compositions) of this
Catalyst (1) was as follows:
Mo.sub.12V.sub.5.5W.sub.1Cu.sub.2,2Sb.sub.0.5Mg.sub.0.5Si.sub.0.75Al.sub.0-
.05.
[0035] The supported ratio was 23.4%.
[0036] [Oxidation Reaction]
[0037] A stainless steel reaction tube of 25 mm in diameter was
charged with 1,000 ml of thus obtained Catalyst (1), and into which
a gaseous mixture of 5 volume % of acrolein, 5.5 volume % of
oxygen, 25 volume % of steam and 64.5 volume % of inert gas
comprising nitrogen and the like was introduced. The reaction was
carried out at 260.degree. C. and at a space velocity (SV) of 1,500
h.sup.-1 (STP). The catalyst performance at the initial period and
after 8,000 hours' reaction was as shown in Table 1.
Comparative Example 1
[0038] Catalyst (2) of the same composition to that of Catalyst (1)
was prepared in the identical manner in Example 1, except that
"Mg/Si--Al-containing compound" was not prepared but each the same
amount to that used in Example 1 of magnesium nitrate, silica sol
and aluminum nitrate were used as they ware. Using this Catalyst
(2), the oxidation reaction was run under identical conditions with
those of Example 1. The result was as shown in Table 1.
Example 2
[0039] [Preparation of Sr/Si--Al-Containing Compound]
[0040] To 74.4 g of 20 weight % silica sol, 10.7 g of strontium
oxide, 0.6 g of cobalt nitrate and 10.5 g of aluminum oxide were
added, mixed and evaporated to dryness under heating to form a
solid matter. The solid was heat-treated at temperatures elevated
stagewisely, followed by 3 hours' calcination at 1,500.degree. C.
Pulverizing the product, a powder (2) having an average particle
diameter of 30 .mu.m was obtained.
[0041] [Preparation of Catalyst]
[0042] Into 2,000 ml of pure water, 350 g of ammonium
paramolybdate, 116 g of ammonium metavanadate and 53.5 g of
ammonium paratungstate were dissolved under heating and stirring.
Separately, into 200 g of pure water, 99.8 g of cupric nitrate and
12 g of antimony trioxide were added under heating and stirring.
The so formed two liquids were mixed, 28.9 g of the powder (2) was
added, and together poured into a porcelain evaporator on hot water
bath. Then 1,200 ml of a silica-alumina spherical carrier having an
average particle diameter of 5 mm was added, followed by
evaporation to dryness under stirring to have the catalyst
deposited on the carrier. The carrier-supported catalyst was
calcined at 400.degree. C. for 6 hours to provide Catalyst (3). The
composition of the metallic elements in this Catalyst (3) was as
follows:
Mo.sub.12V.sub.6W.sub.1.2Cu.sub.2.5Sb.sub.0.5Sr.sub.0.5Si.sub.1.2Al.sub.1C-
o.sub.0.01.
[0043] The supported ratio was 24.8%.
[0044] [Oxidation Reaction]
[0045] The reaction was carried out under identical conditions with
those in Example 1, except that Catalyst (1) was replaced with
Catalyst (3). The result was as shown in Table 1.
Example 3
[0046] [Preparation of Ca--Ba/Si--Al-Containing Compound]
[0047] Into 200 ml of pure water, 48.8 g of calcium nitrate, 54 g
of barium nitrate and 0.9 g of sodium nitrate were dissolved under
heating and stirring. To this solution 335 g of 20 weight % silica
sol and 33.7 g of aluminum oxide were added, mixed and evaporated
to dryness under heating to provide a solid matter. Thus obtained
solid was heat-treated at temperatures elevated stagewisely,
followed by 3 hours' calcination at 1,400.degree. C. Pulverizing
the product, a powder (3) having an average particle diameter of 30
.mu.m was obtained.
[0048] [Preparation of Catalyst]
[0049] Into 2,000 ml of pure water, 350 g of ammonium
paramolybdate, 96.6 g of ammonium metavanadate and 44.6 g of
ammonium paratungstate were dissolved under heating and stirring.
Separately, 99.8 g of cupric nitrate was dissolved in 200 g of pure
water under heating and stirring. Thus formed two solutions were
mixed, to which 115.5 g of the powder (3) was added and together
poured into a porcelain evaporator on hot water bath. Then 1,200 ml
of a silica-alumina spherical carrier having an average particle
diameter of 5 mm was added and evaporated to dryness to have the
catalyst deposited on the carrier, followed by 6 hours' calcination
at 400.degree. C. to provide Catalyst (4). The composition of the
metallic elements of this Catalyst (4) was as follows:
Mo.sub.12V.sub.5W.sub.1Cu.sub.2.5Ca.sub.1Ba.sub.1Si.sub.5.4Al.sub.3.2Na.su-
b.0.05.
[0050] The supported ratio was 26.7%.
[0051] [Oxidation Reaction]
[0052] The reaction was carried out under identical conditions with
those in Example 1, except that Catalyst (1) was replaced with
Catalyst (4). The result was as shown in Table 1.
Example 4
[0053] [Preparation of Mg/Si--Al-Containing Compound]
[0054] Into 400 ml of pure water, 12.7 g of magnesium nitrate, 0.2
g of potassium nitrate and 1.0 g of iron nitrate were dissolved
under heating and stirring. Into this solution 220 g of 20 wt %
silica sol and 1.8 g of aluminum oxide were added, mixed and
evaporated to dryness under heating to provide a solid matter. The
solid was heat-treated under temperatures raised stagewisely,
followed by 3 hours' calcination at 1,200.degree. C. The product
was pulverized to provide a powder (4) having an average particle
diameter of 30 .mu.m.
[0055] [Preparation of Catalyst]
[0056] Into 2,000 ml of pure water, 350 g of ammonium
paramolybdate, 116 g of ammonium metavanadate and 67 g of ammonium
paratungstate were dissolved under heating and stirring.
Separately, 99.8 g of cupric nitrate was dissolved in 200 g of pure
water under heating and stirring. Thus formed two solutions were
mixed, and to which 186 g of the powder (4) was added and together
put into a porcelain evaporator on hot water bath. Then 1,200 ml of
a silica-alumina spherical carrier having an average diameter of 5
mm was added, followed by evaporation to dryness under stirring to
have the catalyst deposited on the carrier. The supported catalyst
was calcined at 400.degree. C. for 6 hours to provide Catalyst (5).
The composition of the metallic elements in this Catalyst (5) was
as follows:
Mo.sub.12V.sub.6W.sub.1.5Cu.sub.2.5Mg.sub.0.2Si.sub.0.3Al.sub.0.02K.sub.0.-
01Fe.sub.0.01.
[0057] The supported ratio was 23.8%.
[0058] [Oxidation Reaction]
[0059] The reaction was carried out under identical conditions with
those in Example 1, except that Catalyst (1) was replaced with
Catalyst (5). The result was as shown in Table 1.
Example 5
[0060] [Preparation of Mg/Si-Containing Compound]
[0061] One-hundred (100) g of magnesium silicate manufactured by
Nakarai Tesqu Co. was calcined at 1,500.degree. C. for 3 hours to
obtain a powder (5).
[0062] [Preparation of Catalyst]
[0063] Into 2,000 ml of pure water, 350 g of ammonium
paramolybdate, 96.6 g of ammonium metavanadate and 53.5 of ammonium
paratungstate were dissolved under heating and stirring.
Separately, 87.8 g of cupric nitrate, 13.0 of titanium dioxide and
4.8 g of antimony trioxide were added to 200 g of pure water under
heating and stirring. Thus obtained two liquids were mixed, 51.7 g
of the powder (5) was added to the liquid mixture and together put
into a porcelain evaporator on hot water bath. Then 1,200 ml of a
silica-alumina spherical carrier having an average particle
diameter of 5 mm was added and evaporated to dryness under stirring
to have the catalyst deposited on the carrier. The supported
catalyst was then calcined at 400.degree. C. for 6 hours to provide
Catalyst (6). The composition of the metallic elements of this
Catalyst (6) was as follows:
Mo.sub.12V.sub.5W.sub.1.2Cu.sub.2.2Sb.sub.0.2Mg.sub.2.4Si.sub.3.6Ti.sub.1.
[0064] The supported ratio was 25.0%.
[0065] [Oxidation Reaction]
[0066] The reaction was carried out under identical conditions with
those in Example 1, except that Catalyst (1) was replaced with
Catalyst (6). The result was as shown in Table 1.
1 TABLE 1 Acrylic Reaction Acrolein Acid Acrylic Catalyst Temp.
conversion Selectivity Acid Yield No. (.degree. C.) (%) (%) (%)
Example 1 (1) Initial stage of reaction 260 99.1 96.0 95.1 After
8,000 hrs. 268 99.2 95.8 95.0 Comparative (2) Initial stage of
reaction 260 97.0 93.8 91.0 Example 1 After 8,000 hrs. 291 97.8
93.1 91.1 Example 2 (3) Initial stage of reaction 260 99.6 95.6
95.2 After 8,000 hrs. 267 99.4 95.4 94.8 Example 3 (4) Initial
stage of reaction 260 99.0 95.4 94.4 After 8,000 hrs. Example 4 (5)
Initial stage of reaction 260 99.0 95.8 94.8 After 8,000 hrs. 271
99.2 95.7 94.9 Example 5 (6) Initial stage of reaction 260 99.1
95.2 94.3 After 8,000 hrs. 274 99.0 94.9 94.0
* * * * *