Title of Invention

A METHOD FOR PRODUCING A CATALYST CONTAINING MOLYBDENUM AND PHOSPHORUS FOR USE IN SYNTHESIZING METHACRYLIC ACID

Abstract The present invention provides a method for producing a catalyst for use in synthesizing methacrylic acid which can produce methacrylic acid in high yield, the catalyst for use in synthesizing methacrylic acid which can produce methacrylic acid in high yield and a method for producing methacrylic acid in high yield through gas-phase catalytic oxidation of methacrolein with molecular oxygen. The method for producing the catalyst containing molybdenum and phosphorus for use in synthesizing methacrylic acid is composed of the steps of: preparing a slurry containing at least molybdenum and phosphorus and having specific viscosity in the range of 2.5 x 10-4 to 7.0 x 10-4 m2/s, which is a value obtained by dividing viscosity (unit: kg/(ms)) by specific gravity (unit: kg/m3); obtaining a dried material by drying the slurry; and calcining the dried material at 300 to 500°C.
Full Text

DESCRIPTION
METHOD FOR PRODUCING CATALYST FOR USE IN SYNTHESIZING
METHACRYLIC ACID
TECHNICAL FIELD
The present invention relates to a method for producing a catalyst for
use in synthesizing methacrylic acid, a catalyst for use in synthesizing
methacrylic acid and a method for producing methacrylic acid through
gas-phase catalytic oxidation of methacrolein with molecular oxygen.
BACKGROUND ART
It is publicly known that a heteropolyacid catalyst containing
molybdenum and phosphorus is effective as a catalyst for use in synthesizing
methacrylic acid through gas-phase catalytic oxidation of methacrolein. For
example, a method for producing a catalyst for use in synthesizing methacrylic
acid is proposed in Patent Document 1 wherein water content of a concentrated
or dried material of a slurry obtained by mixing compounds containing
catalyst-component elements is adjusted to 5 to 20% by mass followed by heat
treatment at 100 to 250°C. A method for producing a catalyst for use in
synthesizing methacrylic acid is proposed in Patent Document 2 wherein water
content of a concentrated or dried material of a slurry obtained by mixing
phosphomolybdic acid and compounds containing other catalyst-component
elements is adjusted to 5 to 20% by mass followed by heat treatment at 100 to
300°C.
Patent Document 1: Japanese Patent Application Laid-Open No. Sho58-51,943
Patent Document 2: Japanese Patent Application Laid-Open No. Sho58-112,050

DISCLOSURE OF INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
However, the catalysts produced by the methods described in Patent
Documents 1 and 2 are industrially insufficient in point of yield of methacrylic
acid, and hence further improvement in yield has been desired.
It is an object of the present invention to provide a method for producing
a catalyst for use in synthesizing methacrylic acid which can produce
methacrylic acid in high yield, the catalyst for use in synthesizing methacrylic
acid which can produce methacrylic acid in high yield, and a method for
producing methacrylic acid in high yield through gas-phase catalytic oxidation of
methacrolein with molecular oxygen.
MEANS FOR SOLVING PROBLEM
The first present invention is a method for producing a catalyst
containing molybdenum and phosphorus for use in synthesizing methacrylic acid,
comprising the steps of:
(a) preparing a slurry containing at least molybdenum and phosphorus
and having specific viscosity in the range of 2.5 x 10-4 to 7.0 x 10-4 m2/s, the
specific viscosity being a value obtained by dividing viscosity (unit: kg/(m-s)) by
specific gravity (unit: kg/m3);
(b) obtaining a dried material by drying the slurry; and
(c) calcining the dried material at 300 to 500°C.
Preferably, in the foregoing step (a), the slurry containing at least
molybdenum and phosphorus and having specific viscosity which is lower than a
target specific viscosity is concentrated to the point where the target specific
viscosity is obtained.

The second present invention is a catalyst containing molybdenum and
phosphorus for use in synthesizing methacrylic acid, produced by the method of
the first invention.
The third present invention is a method for producing methacrylic acid
through gas-phase catalytic oxidation of methacrolein with molecular oxygen by
using the catalyst containing molybdenum and phosphorus for use in
synthesizing methacrylic acid of the second invention.
EFFECT OF THE INVENTION
According to the first present invention, a catalyst for use in synthesizing
methacrylic acid which can produce methacrylic acid in high yield can be
produced.
By using the catalyst for use in synthesizing methacrylic acid of the
second present invention, methacrylic acid can be produced in high yield.
According to the method for producing methacrylic acid of the third
present invention, methacrylic acid can be produced in high yield through
gas-phase catalytic oxidation of methacrolein with molecular oxygen.
BEST MODE FOR CARRYING OUT THE INVENTION
The catalyst for use in synthesizing methacrylic acid which is produced
by the method of the present invention (hereinafter, also merely expressed as
catalyst) is a composite oxide containing at least molybdenum and phosphorus.
The composite oxide preferably contains a structure of heteropolyacid and/or
heteropolyacid salt. The fact that the catalyst is the composite oxide and
contains the structure of heteropolyacid and/or heteropolyacid salt can be
confirmed with XRD.
Further, the catalyst preferably contains an alkaline metal besides

molybdenum and phosphorus, and may contain, in addition to these elements,
copper, vanadium, iron, cobalt, nickel, zinc, magnesium, calcium, strontium,
barium, titan, chromium, tungsten, manganese, silver, boron, silicon, aluminum,
gallium, germanium, tin, lead, arsenic, antimony, bismuth, niobium, tantalum,
zirconium, indium, sulfur, selenium, tellurium, lanthanum, cerium, or the like.
The catalyst is preferably the composite oxide represented by the following
compositional formula (1).

In the formula (1), Mo, P, Cu, V and O represent molybdenum,
phosphorus, copper, vanadium, and oxygen, respectively; X represents at least
one element selected from the group consisting of potassium, rubidium, cesium,
and thallium; Y represents at least one element selected from the group
consisting of iron, cobalt, nickel, zinc, magnesium, calcium, strontium, barium,
titan, chromium, tungsten, manganese, silver, boron, silicon, aluminum, gallium,
germanium, tin, lead, arsenic, antimony, bismuth, niobium, tantalum, zirconium,
indium, sulfur, selenium, tellurium, lanthanum, and cerium; a, b, c, d, e, f, and g
represent atomic ratios of respective elements; when a is 12, b is in the range of
from 0.1 to 3, c is in the range of from 0.01 to 3, d is in the range of from 0.01 to 3,
e is in the range of from 0.01 to 3, f is in the range of from 0 to 3, and g
represents the atomic ratio of oxygen necessary for fulfilling the requirement of
the atomic ratio of each component above.
In the method for producing the catalyst of the present invention, a slurry
containing at least molybdenum and phosphorus and having specific viscosity in
the range of 2.5 x 10-4 to 7.0 x 10-4 m2/s, which is a value obtained by dividing
viscosity (unit: kg/(m-s)) by specific gravity (unit: kg/m3) (hereinafter, also merely
expressed as slurry), is prepared (step (a)); the slurry is dried (step (b)); and the
dried material thus obtained is calcined at 300 to 500°C (step (c)).

The slurry containing at least molybdenum and phosphorus and having
the specified specific viscosity mentioned above can be prepared, using raw
materials of respective component elements of the catalyst (hereinafter,
expressed as catalyst raw materials), with conventional coprecipitation method,
oxide mixing method, or the like. The catalyst raw materials to be used in the
preparation of the slurry are not particularly limited and nitrates, carbonates,
acetates, ammonium salts, oxides, halides, oxoacids, and oxoacid salts of
respective component elements of the catalyst can be used in combination. As
the raw material of molybdenum, for example, ammonium paramolybdate,
molybdenum trioxide, molybdic acid, and molybdenum chloride can be used.
As the raw material of phosphorus, for example, phosphoric acid, phosphorus
pentoxide, and ammonium phosphate can be used. As the solvent, for
example, water, ethyl alcohol, and acetone can be listed and water is preferably
used.
As the preferable procedure for preparing the slurry, for example, a
method of suspending in water the raw material of molybdenum such as a
molybdenum oxide or ammonium paramolybdate followed by mixing the other
catalyst raw materials with the suspension thus obtained is listed. The other
catalyst raw materials can be used as they are or by properly dissolving or
suspending them in liquid media such as water. Further, aqueous ammonia
may be added in the course of mixing the catalyst raw materials or after the
mixing.
The foregoing slurry having the specified specific viscosity, for example,
can be produced by concentrating the slurry having specific viscosity which is
lower than the target specific viscosity. Concentration means the operation of
heating the slurry and vaporizing the solvent in the slurry. The concentration,
for example, can be carried out by heating a vessel such as a reaction vessel

containing the slurry using heat source such as electric heater or steam. The
temperature of the slurry at the time of the concentration is not particularly
limited, however, it is preferably 50°C to 110°C, more preferably 90°C to 108°C,
furthermore preferably 95°C to 105°C. The viscosity and the specific gravity of
the slurry during the concentration are properly measured by sampling the slurry,
and the concentration is finished when the specific viscosity reaches the target
specific viscosity in the range of 2.5 x 10-4 to 7.0 x 10-4 m2/s, preferably in the
range of 3.0 x 10-4 to 6.5 x 10-4 m2/s. Specific viscosity is a value calculated by
dividing the viscosity (unit: kg/(ms)) by the specific gravity (unit: kg/m3).
Viscosity is measured by sampling a portion of the slurry and using B type
viscometer. The measurement of the viscosity is preferably carried out after the
slurry is stirred. Specific gravity is calculated by sampling a portion of the slurry,
measuring its mass and its volume and dividing the mass by the volume.
Measurements of the viscosity and the specific gravity of the slurry during its
concentration may be carried out either continuously or intermittently, however, it
is preferable to carry out intermittently at intervals of within 5 minutes.
"Concentration is finished" means that vaporization of water is
suppressed as far as possible by a method of, for example, stopping heating.
Concretely, it is preferable to stop heating and put the lid on the reaction vessel.
In the present invention, the prepared slurry having the specified specific
viscosity can be dried immediately, however, it can also be stored in the state of
slurry before dried. When the slurry is stored, the specific viscosity of the slurry
is kept in the range of 2.5 x 10-4 to 7.0 x 10-4 m2/s, preferably in the range of 3.0
x 10-4 to 6.5 x 10-4 m2/s. The storage time of the slurry is not particularly limited
as long as the specific viscosity of the slurry is within the foregoing range.
However, the storage time is preferably 30 days or less, more preferably 5 days
or less, because the productivity of the catalyst becomes higher as the storage

time becomes shorter.
In the present invention, the slurry having the specific viscosity in the
range of 2.5 x 10-4 to 7.0 x 10-4 m2/s is dried (step (b)). For drying, a device that
can dry the slurry in a short time such as spray dryer, drum dryer and slurry dryer
can be used. The temperature at the time of drying is not particularly limited,
however, it is preferably 120°C to 500°C, more preferably 130°C to 400°C,
furthermore preferably 140 °C to 350 °C. The drying time is not particularly
limited, however, it is preferably 0.1 second to 10 minutes, more preferably 0.3
second to 5 minutes. Drying is preferably carried out to the extent that the
water content of the dried material to be obtained becomes less than 3% by
mass. Water content of the dried material can be measured with Kett Moisture
Tester by sampling a portion of it.
Subsequently, the dried material thus obtained is calcined at 300 to
500°C, preferably at 300 to 450°C. The calcination is ordinarily carried out under
the flow of oxygen-containing gas such as air and/or under the flow of inert gas.
The calcination time is ordinarily 0.5 hour or more, preferably 1 to 40 hours.
When the molded catalyst is produced, the calcined material obtained by
calcining the dried material without modification may be molded, however, it is
preferable to previously mold the dried material and then calcine the molded
article thus obtained. The method of molding is not particularly limited and
various molding methods such as tablet molding, extrusion molding and
granulation can be used. When molding is carried out, additives or filling
materials such as inorganic salts which include barium sulfate and ammonium
sulfate; lubricants which include graphite; organic materials which include
cellulose, starch, polyvinyl alcohol, and stearic acid; hydroxyl sols which include
silica sol and alumina sol; and inorganic fibers which include whisker, glass fiber,
and carbon fiber may be properly added with the view of producing molded

articles having a uniform specific surface area, pore volume, and pore
distribution in good reproducibility, improving mechanical strength of the molded
articles, or the like. The shape of the molded article is not particularly limited
and spherical shape, cylindrical shape, ring shape or plate shape can be listed.
The reason why the catalyst that can produce methacrylic acid in high
yield can be produced by carrying out the above-mentioned procedure is not
clear, however, it is presumed that an intermediate of the crystal structure which
functions advantageously in gas-phase catalytic oxidation reaction of
methacrolein be formed when the specific viscosity of the slurry is in the
foregoing specified range.
Next, the method for producing methacrylic acid through gas-phase
catalytic oxidation of methacrolein with molecular oxygen by using the catalyst of
the present invention thus obtained will be explained.
In the gas-phase catalytic oxidation (hereinafter, also merely expressed
as reaction), the raw gas containing at least methacrolein and molecular oxygen
is contacted with the catalyst. Ordinarily, a tubular reactor filled with the catalyst
is used for the reaction. Industrially, a multitubular reactor is used.
Concentration of methacrolein in the raw gas to be used in the reaction
can be set in a wide range, however, it is preferably 1 to 20% by volume,
particularly preferably 3 to 10% by volume. The raw methacrolein sometimes
contains a small amount of impurities such as water, lower saturated aldehydes,
and the like which do not substantially affect the reaction, and the raw gas may
also contain those impurities originating from methacrolein.
The amount of molecular oxygen in the raw gas is preferably 0.4 to 4
times by mole as much as that of methacrolein, particularly preferably 0.5 to 3
times by mole. As a source of molecular oxygen in the raw gas, using air is
industrially advantageous, however if necessary, pure oxygen-enriched air can

be used. Further, the raw gas is preferably diluted with an inert gas such as
nitrogen or carbon dioxide, steam, or the like.
The reaction pressure is preferably from atmospheric pressure to 5 atm,
more preferably from atmospheric pressure to 3 atm. The reaction temperature
is preferably 200 to 450°C, more preferably 250 to 400°C. The contact time of
the raw gas with the catalyst is preferably 1.5 to 15 seconds, more preferably 2
to 7 seconds.
EXAMPLES
Hereinafter, the present invention will be explained with reference to
Examples and Comparative Examples. The term "part(s)" in the Examples and
Comparative Examples means part(s) by mass. Quantitative analysis of the
raw gas and the products were carried out with gas chromatography.
Conversion of the raw methacrolein, selectivity to and per pass yield of the
product methacrylic acid are defined as follows:
Conversion of methacrolein (%) = (B/A) x 100;
Selectivity to methacrylic acid (%) = (C/B) x 100; and
Per pass yield of methacrylic acid (%) = (C/A) x 100.
In these formulae, A represents mole number of methacrolein supplied,
B represents mole number of methacrolein reacted and C represents mole
number of methacrylic acid produced.
In the Examples and Comparative Examples, viscosity (kg/(m-s)) of the
slurry was measured by B type viscometer after sampling a portion of the slurry,
and sufficiently stirring the sample not to segregate the solids constituent.
Specific gravity (kg/m3) of the slurry was calculated by sampling a portion of the
slurry, measuring its volume (m3) and its mass (kg) and dividing the mass by the
volume. During concentration of the slurry, these measurement were carried
out at intervals of 5 minutes. Specific viscosity (m2/s) was calculated by

dividing the viscosity (kg/(m.s)) by the specific gravity (kg/m3). Water content of
the dried material was measured with Kett Moisture Tester.
The fact that the catalyst is a composite oxide and contains the structure
of heteropolyacid and/or its salt was confirmed with XRD.
Example 1
To 400 parts of pure water, 100 parts of molybdenum trioxide, 7.3 parts
of 85% by mass aqueous phosphoric acid, 4.2 parts of vanadium pentoxide, 0.9
part of copper oxide, and 0.2 part of iron oxide were added and stirred under
reflux condition for 5 hours. The resultant liquid was cooled to 50°C and 37.4
parts of 29% by mass aqueous ammonia was dropped to it and stirred for 15
minutes. Subsequently, a solution obtained by dissolving 9.0 parts of cesium
nitrate in 30 parts of pure water was dropped to it and stirred for 15 minutes to
obtain a slurry.
The slurry was heated to 101°C and the concentration was started while
it was stirred. At the beginning of the concentration, the viscosity of the slurry
was 0.03 kg/(m-s), the specific gravity was 1.25 x 103 kg/m3, and the specific
viscosity was 2.4 x 10-5 m2/s. The temperature was kept at 101°C during the
concentration, and heating was stopped and the concentration was finished
when the viscosity of the slurry was 0.70 kg/(m-s), the specific gravity was 1.56 x
103 kg/m3, and the specific viscosity was 4.5 x 10-4 m2/s. The time spent for the
concentration was 2 hours.
The slurry right after the concentration was dried with a spray dryer at
the inlet temperature of 300°C and the outlet temperature of 120°C. The water
content of the dried material thus obtained was 0.9% by mass. To 100 parts of
the dried material, 2 parts of graphite was added and the mixture thus obtained
was molded to ring shape having an outer diameter of 5 mm, an inner diameter
of 2 mm, and a length of 5 mm with a tablet molding machine. The molded

articles thus obtained were calcined at 375°C for 10 hours under air flow and a
composite oxide catalyst having the composition of Mo12P1.1Cu0.2V0.8Cs0.8Fe0.05
(oxygen and its atomic ratio were abbreviated, and the same hereinafter) and
containing the structure of heteropolyacid and its salt was obtained.
The catalyst was filled in a reactor and mixed gas composed of 5% of
methacrolein, 10% of oxygen, 30% of water vapor, and 55% of nitrogen
(volume%) was passed through it with the reaction pressure of 1013 hPa
(pressure at the exit of the reactor), the reaction temperature of 285°C, and the
contact time of 3.6 seconds to carry out the reaction for synthesizing methacrylic
acid. The result is shown in Table 1.
Example 2
The same procedure as in Example 1 was carried out except that the
concentration was finished when the viscosity of the slurry was 0.53 kg/(ms), the
specific gravity was 1.52 x 103 kg/m3, and the specific viscosity was 3.5 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Example 3
The same procedure as in Example 1 was carried out except that the
concentration was finished when the viscosity of the slurry was 0.88 kg/(m.s), the
specific gravity was 1.60 x 103 kg/m3, and the specific viscosity was 5.5 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Comparative Example 1
The same procedure as in Example 1 was carried out except that the
concentration was finished when the viscosity of the slurry was 1.30 kg/(m.s), the
specific gravity was 1.63 x 103 kg/m3, and the specific viscosity was 8.0 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize

methacrylic acid. The result is shown in Table 1.
Comparative Example 2
The same procedure as in Example 1 was carried out except that the
concentration was finished when the viscosity of the slurry was 1.50 kg/(m.s), the
specific gravity was 1.67 x 103 kg/m3, and the specific viscosity was 9.0 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Comparative Example 3
The same procedure as in Example 1 was carried out except that the
concentration was finished when the viscosity of the slurry was 0.27 kg/(m.s), the
specific gravity was 1.35 x 103 kg/m3, and the specific viscosity was 2.0 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Comparative Example 4
The same procedure as in Example 1 was carried out except that the
concentration was finished when the viscosity of the slurry was 0.10 kg/(ms), the
specific gravity was 1.25 x 103 kg/m3, and the specific viscosity was 8.0 x 10-5
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Example 4
In 200 parts of pure water, 100 parts of ammonium paramolybdate was
dissolved, and to the resultant solution, 3.4 parts of ammonium methavanadate,
a solution obtained by dissolving 8.2 parts of 85% by mass aqueous phosphoric
acid in 30 parts of pure water, a solution obtained by dissolving 1.1 parts of
copper nitrate in 30 parts of pure water, and a solution obtained by dissolving 3.8
parts of iron nitrate in 10 parts of pure water were added in this order, and the
resultant liquid was heated to 90°C while stirred, and kept at 90°C while stirred

for 5 hours. To the resultant liquid, a solution obtained by dissolving 9.2 parts of
cesium nitrate in 100 parts of pure water was added and stirred for 15 minutes to
obtain a slurry.
The slurry was heated to 101°C and the concentration was started while
it was stirred. At the beginning of the concentration, the viscosity of the slurry
was 0.02 kg/(ms), the specific gravity was 1.22 x 103 kg/m3, and the specific
viscosity was 1.6 x 10-5 m2/s. The temperature was kept at 101°C during the
concentration, and heating was stopped and the concentration was finished
when the viscosity of the slurry was 0.68 kg/(m.s), the specific gravity was 1.58 x
103 kg/m3 and the specific viscosity was 4.3 x 10-4 m2/s. The time spent for the
concentration was 2.5 hours.
The slurry right after the concentration was dried with a drum dryer at the
temperature of 300°C. The water content of the dried material thus obtained
was 1.0% by mass. To 100 parts of the dried material, 2 parts of graphite was
added and the mixture thus obtained was molded to ring shape having an outer
diameter of 5 mm, an inner diameter of 2 mm, and a length of 5 mm with a tablet
molding machine. The molded articles thus obtained were calcined at 380°C
for 6 hours under air flow and a composite oxide catalyst having the composition
of Mo12P1.5Cu0.1V0.6Cs1Fe0.2 and containing the structure of heteropolyacid and
its salt was obtained.
The catalyst was filled in a reactor and mixed gas composed of 5% of
methacrolein, 10% of oxygen, 30% of water vapor, and 55% of nitrogen
(volume%) was passed through it with the reaction pressure of 1013 hPa
(pressure at the exit of the reactor), the reaction temperature of 285°C, and the
contact time of 3.6 seconds to carry out the reaction for synthesizing methacrylic
acid. The result is shown in Table 1.
Example 5

The same procedure as in Example 4 was carried out except that the
concentration was finished when the viscosity of the slurry was 0.85 kg/(m.s), the
specific gravity was 1.60 x 103 kg/m3, and the specific viscosity was 5.3 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Comparative Example 5
The same procedure as in Example 4 was carried out except that the
concentration was finished when the viscosity of the slurry was 0.26 kg/(ms), the
specific gravity was 1.37 x 103 kg/m3, and the specific viscosity was 1.9 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Comparative Example 6
The same procedure as in Example 4 was carried out except that the
concentration was finished when the viscosity of the slurry was 1.30 kg/(m.s), the
specific gravity was 1.65 x 103 kg/m3, and the specific viscosity was 7.9 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Example 6
To 800 parts of pure water, 100 parts of molybdenum trioxide, 3.1 parts
of vanadium pentoxide, and 6.7 parts of 85% by mass aqueous phosphoric acid
were added and stirred under reflux condition for 6 hours. To the liquid thus
obtained, 2.4 parts of copper acetate was added and further stirred under reflux
condition for 3 hours. The resultant liquid was cooled to 40°C and a solution
obtained by dissolving 11.2 parts of cesium bicarbonate in 100 parts of pure
water was dropped to it and a solution obtained by dissolving 5.6 parts of
ammonium carbonate in 100 parts of pure water was further dropped to it at
40°C and stirred for 15 minutes to obtain a slurry.

The slurry was heated to 101°C and the concentration was started while
it was stirred. At the beginning of the concentration, the viscosity of the slurry
was 0.02 kg/(m.s), the specific gravity was 1.11 x 103 kg/m3, and the specific
viscosity was 1.8 x 10-5 m2/s. The temperature was kept at 101°C during the
concentration, and heating was stopped and the concentration was finished
when the viscosity of the slurry was 0.59 kg/(ms), the specific gravity was 1.31 x
103 kg/m3, and the specific viscosity was 4.5 x 10-4 m2/s. The time spent for the
concentration was 2.3 hours.
The slurry right after the concentration was dried with a spray dryer at
the inlet temperature of 300°C and the outlet temperature of 120°C. The water
content of the dried material thus obtained was 0.8% by mass. To 100 parts of
the dried material, 2 parts of graphite was added and the mixture thus obtained
was molded to ring shape having an outer diameter of 5 mm, an inner diameter
of 2 mm, and a length of 5 mm with a tablet molding machine. The molded
articles thus obtained were calcined at 380°C for 5 hours under air flow and a
composite oxide catalyst having the composition of Mo12P1Cu0.2V0.6Cs1 and
containing the structure of heteropolyacid and its salt was obtained.
The catalyst was filled in a reactor and mixed gas composed of 5% of
methacrolein, 10% of oxygen, 30% of water vapor, and 55% of nitrogen
(volume%) was passed through it with the reaction pressure of 1013 hPa
(pressure at the exit of the reactor), the reaction temperature of 285°C, and the
contact time of 3.6 seconds to carry out the reaction for synthesizing methacrylic
acid. The result is shown in Table 1.
Example 7
The same procedure as in Example 6 was carried out except that the
concentration was finished when the viscosity of the slurry was 0.80 kg/(m.s), the
specific gravity was 1.33 x 103 kg/m3, and the specific viscosity was 6.0 x 10-4

m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Comparative Example 7
The same procedure as in Example 6 was carried out except that the
concentration was finished when the viscosity of the slurry was 0.25 kg/(m.s), the
specific gravity was 1.25 x 103 kg/m3, and the specific viscosity was 2.0 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.
Comparative Example 8
The same procedure as in Example 6 was carried out except that the
concentration was finished when the viscosity of the slurry was 1.30 kg/(m.s), the
specific gravity was 1.41 x 103 kg/m3, and the specific viscosity was 9.2 x 10-4
m2/s, to produce the catalyst of the same composition and to synthesize
methacrylic acid. The result is shown in Table 1.



WE CLAIM:
1. A method for producing a catalyst containing molybdenum and
phosphorus for use in synthesizing methacrylic acid, comprising the
steps of:
(a) preparing a slurry containing at least molybdenum and phosphorus
and having specific viscosity which is lower than a target specific
viscosity is concentrated to the point where the target specific viscosity in
the range of 2.5x10-4 to 7.0x10-4 m2/s, is obtained, the specific viscosity
being a value obtained by dividing viscosity (unit:kg/(m.s)) by specific
gravity (unit: kg/m3);
(b) obtaining a dried material by drying the slurry; and
(c)calcining the dried material at 300 to 500°C.
2. The method as claimed in claim 1 for producing a catalyst containing
molybdenum and phosphorus for producing methacrylic acid through
gas-phase catalytic oxidation of methacrolein with molecular oxygen.



ABSTRACT


The present invention provides a method for producing a catalyst for use
in synthesizing methacrylic acid which can produce methacrylic acid in high yield,
the catalyst for use in synthesizing methacrylic acid which can produce
methacrylic acid in high yield and a method for producing methacrylic acid in
high yield through gas-phase catalytic oxidation of methacrolein with molecular
oxygen. The method for producing the catalyst containing molybdenum and
phosphorus for use in synthesizing methacrylic acid is composed of the steps of:
preparing a slurry containing at least molybdenum and phosphorus and having
specific viscosity in the range of 2.5 x 10-4 to 7.0 x 10-4 m2/s, which is a value
obtained by dividing viscosity (unit: kg/(ms)) by specific gravity (unit: kg/m3);
obtaining a dried material by drying the slurry; and calcining the dried material at
300 to 500°C.

Documents:

00075-kolnp-2007-correspondence-1.1.pdf

00075-kolnp-2007-correspondence-1.2.pdf

00075-kolnp-2007-correspondence-1.3.pdf

00075-kolnp-2007-international search authority report-1.1.pdf

00075-kolnp-2007-others document.pdf

00075-kolnp-2007-p.a.pdf

0075-kolnp-2007 abstract.pdf

0075-kolnp-2007 claims.pdf

0075-kolnp-2007 correspondence others.pdf

0075-kolnp-2007 description (complete).pdf

0075-kolnp-2007 form-1.pdf

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0075-kolnp-2007 form-5.pdf

0075-kolnp-2007 international publication.pdf

0075-kolnp-2007 international search authority report.pdf

0075-kolnp-2007 pct form.pdf

0075-kolnp-2007 priority document.pdf

75-KOLNP-2007-(22-10-2013)-CLAIMS.pdf

75-KOLNP-2007-(22-10-2013)-CORRESPONDENCE.pdf

75-KOLNP-2007-(22-10-2013)-FORM-1.pdf

75-KOLNP-2007-(22-10-2013)-FORM-2.pdf

75-KOLNP-2007-CANCELLED PAGES.pdf

75-KOLNP-2007-CORRESPONDENCE 1.1.pdf

75-KOLNP-2007-CORRESPONDENCE.pdf

75-KOLNP-2007-DESCRIPTION (COMPLETE) 1.1.pdf

75-KOLNP-2007-ENGLISH TRANSLATION.pdf

75-KOLNP-2007-EXAMINATION REPORT REPLY RECIEVED.pdf

75-KOLNP-2007-EXAMINATION REPORT.pdf

75-KOLNP-2007-FORM 1-1.1.pdf

75-kolnp-2007-form 18.pdf

75-KOLNP-2007-FORM 2-1.1.pdf

75-KOLNP-2007-FORM 26.pdf

75-KOLNP-2007-FORM 3-1.1.pdf

75-KOLNP-2007-FORM 5-1.1.pdf

75-KOLNP-2007-GRANTED-ABSTRACT.pdf

75-KOLNP-2007-GRANTED-CLAIMS.pdf

75-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

75-KOLNP-2007-GRANTED-FORM 1.pdf

75-KOLNP-2007-GRANTED-FORM 2.pdf

75-KOLNP-2007-GRANTED-FORM 3.pdf

75-KOLNP-2007-GRANTED-FORM 5.pdf

75-KOLNP-2007-GRANTED-SPECIFICATION-COMPLETE.pdf

75-KOLNP-2007-INTERNATIONAL PUBLICATION.pdf

75-KOLNP-2007-INTERNATIONAL SEARCH REPORT & OTHERS.pdf

75-KOLNP-2007-OTHERS 1.1.pdf

75-KOLNP-2007-OTHERS.pdf

75-KOLNP-2007-PETITION UNDER RULE 137.pdf

75-KOLNP-2007-PETITION UNDER RULE-137.pdf

75-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf


Patent Number 258003
Indian Patent Application Number 75/KOLNP/2007
PG Journal Number 48/2013
Publication Date 29-Nov-2013
Grant Date 27-Nov-2013
Date of Filing 05-Jan-2007
Name of Patentee MITSUBISHI RAYON CO. LTD.
Applicant Address 6-41, KONAN 1-CHOME, MINATO-KU, TOKYO 108-8506
Inventors:
# Inventor's Name Inventor's Address
1 TOMOKI FUKUI C/O CORPORATE RESEARCH LABORATORIES,MITSUBISHI RAYON CO.,LTD., 20-1, MIYUKICHO,OTAKE-SHI,HIROSHIMA 739-0693
2 TOMOMICHI HINO C/O OTAKE PLANTS, MITSUBISHI RAYON CO.,LTD., 20-1, MIYUKICHO,OTAKE-SHI, HIROSHIMA 739-0693
3 HIROYUKI NAITOU C/O CORPORATE RESEARCH LABORATORIES,MITSUBISHI RAYON CO.,LTD., 20-1, MIYUKICHO,OTAKE-SHI,HIROSHIMA 739-0693
PCT International Classification Number B01J 37/00
PCT International Application Number PCT/JP2005/011590
PCT International Filing date 2005-06-24
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2004-189888 2004-06-28 Japan