JP2003001111A - Method for manufacturing catalyst for synthesizing methacrylic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a methacrylic acid synthesis catalyst that excels in activation and selectivity of methacrylic acid. SOLUTION: A solid material A, which contains at least molybdenum, phosphorus and X (wherein, X represents at least one kind of element selected from the group consisting of potassium, rubidium, cesium and thallium), and a solid material B, which contains at least molybdenum and phosphorus, and doesn't contain X, are dry-mixed and thereafter formed, and an obtained formed material is fired at 300 to 500 deg.C. The solid material A is preferably obtained by drying an aqueous slurry containing at least molybdenum, phosphorus and X. Further the solid material B is preferably obtained by drying the aqueous slurry containing at least molybdenum and phosphorus, and not containing X.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a methacrylic acid synthesizing catalyst which is used when methacrolein is subjected to gas phase catalytic oxidation with molecular oxygen to synthesize methacrylic acid.

[0002]

2. Description of the Related Art A method for producing a catalyst containing molybdenum and phosphorus as main components, which is a typical catalyst used in the synthesis of methacrylic acid by vapor-phase catalytic oxidation of methacrolein, is disclosed, for example, in JP-A-50-101316. JP-A-53-37614, JP-A-54-103819
JP-A-57-120547, JP-A-60-60
The methods described in JP-A-239439 and JP-A No. 2-240043 are known. The method for producing the catalyst described in these documents is to dry one type of aqueous slurry containing each metal component, and after molding, the catalyst obtained by this method, the activity and The selectivity to methacrylic acid is insufficient as an industrial catalyst.

On the other hand, JP-A-5-177141 discloses that when a heteropolyacid catalyst containing molybdenum, phosphorus and cesium is prepared, molybdenum and phosphorus are added to a suspension of a heteropolyacid salt containing molybdenum, phosphorus and cesium. A method of adding a liquid catalyst raw material containing phosphorus but not cesium is disclosed. In the same publication, it is presumed that the catalyst produced by this method has a structure in which the crystal particle surface of the heteropolyacid salt containing molybdenum, phosphorus and cesium is covered with the heteropolyacid containing no cesium. However, even with the catalyst produced by such a method, the activity and the selectivity to methacrylic acid are insufficient as an industrial catalyst.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a catalyst for methacrylic acid synthesis which is excellent in activity and selectivity to methacrylic acid.

[0005]

According to the present invention, a solid material containing at least molybdenum, phosphorus and X (X represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium). A and a solid B containing at least molybdenum and phosphorus and not containing X are dry-mixed and then molded, and the obtained molded product is 300
It is a method for producing a catalyst for methacrylic acid synthesis, which is fired at ˜500 ° C.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Solid A is a solid containing at least molybdenum, phosphorus and X. Here, X represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium. Solid A
The method for preparing is not particularly limited, but various methods such as coprecipitation, evaporation to dryness, and oxide mixing can be used. In particular, it is preferably prepared by drying an aqueous slurry containing at least molybdenum, phosphorus and X. At this time, the drying method of the aqueous slurry is not particularly limited, and examples of the dryer used include a box dryer, a spray dryer, a drum dryer, a slurry dryer and the like. The solid A may be substantially solid and may contain water. The form of the solid A is not particularly limited, but powder is particularly preferable. In addition, in the process of preparing the solid A, 30
It is desirable that the step of heat treatment at 0 ° C. or higher is not included. The solid A usually has a heteropolyacid salt structure, but it does not necessarily have to have a heteropolyacid salt structure.

The raw material used for preparing the solid A is not particularly limited, and nitrates, carbonates, acetates, ammonium salts, oxides, halides and the like of each element can be used in combination. As the molybdenum raw material, for example, ammonium paramolybdate, molybdenum trioxide, molybdic acid, molybdenum chloride or the like can be used. As the phosphorus raw material, for example, phosphoric acid, phosphorous acid, phosphorus oxide, phosphorus pentachloride and the like can be used.

The solid A is not particularly limited as long as it is a complex oxide containing at least molybdenum, phosphorus and X, but its preferable elemental composition is represented by the following formula (2). Mo _a P _b Cu _c V _d X _e Y _f O _g (2) In the formula (2), Mo, P, Cu, V and O represent molybdenum, phosphorus, copper, vanadium and oxygen, and X
Is at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, Y is iron, cobalt, nickel, zinc, magnesium, calcium,
Selected from the group consisting of strontium, barium, titanium, chromium, tungsten, manganese, silver, boron, silicon, tin, lead, arsenic, antimony, bismuth, niobium, tantalum, zirconium, indium, sulfur, selenium, tellurium, lanthanum and cerium. At least 1
Represents a seed element. However, a, b, c, d, e, f and g represent the atomic ratio of each element, and when a = 12, 0.1
≦ b ≦ 3, 0.01 ≦ c ≦ 3, 0.01 ≦ d ≦ 3, 1 ≦
e ≦ 5, preferably 1.5 ≦ e ≦ 4, 0 ≦ f ≦ 3, and g is the atomic ratio of oxygen required to satisfy the atomic ratio of each component.

Although the method for preparing the solid B is not particularly limited,
As with the solid A, various methods such as a coprecipitation method, a dry evaporation method, and an oxide mixing method can be used. In particular, it is preferable to prepare by drying an aqueous slurry containing at least molybdenum and phosphorus and not containing X. At this time, the method for drying the aqueous slurry is not particularly limited, and a box dryer, a spray dryer, a drum dryer, a slurry dryer or the like can be used as in the case of the solid A. The solid B may be substantially solid, and may contain water. Further, its form is not particularly limited, but powder form is particularly preferable. Further, it is desirable that the step of heat treatment at 300 ° C. or higher is not included in the preparation process. Further, the solid B does not necessarily have the structure of a heteropolyacid or a heteropolyacid salt.

The raw materials used for preparing the solid B are not particularly limited, and as with the solid A, nitrates, carbonates, acetates, ammonium salts, oxides, halides and the like of each element may be used in combination. it can. As the molybdenum raw material, for example, ammonium paramolybdate, molybdenum trioxide, molybdic acid, molybdenum chloride or the like can be used. As the phosphorus raw material, for example, phosphoric acid, phosphorous acid, phosphorus oxide, phosphorus pentachloride and the like can be used.

The solid B is not particularly limited as long as it is a complex oxide containing at least molybdenum and phosphorus and not containing X, but its preferable elemental composition is represented by the following formula (3). Mo _a P _b Cu _c V _d Y _f O _g (3) In the formula (3), Mo, P, Cu, V and O represent molybdenum, phosphorus, copper, vanadium and oxygen, respectively.
Y is iron, cobalt, nickel, zinc, magnesium, calcium, strontium, barium, titanium, chromium, tungsten, manganese, silver, boron, silicon, tin, lead, arsenic, antimony, bismuth, niobium, tantalum, zirconium, indium, It represents at least one element selected from the group consisting of sulfur, selenium, tellurium, lanthanum and cerium. However, a, b, c, d,
e, f and g represent the atomic ratio of each element, and when a = 12, 0.1 ≦ b ≦ 3, 0.01 ≦ c ≦ 3, 0.01 ≦ d
≦ 3, 0 ≦ f ≦ 3, and g is the atomic ratio of oxygen required to satisfy the atomic ratio of each component.

The solid A and the solid B are mixed by a dry method, that is, substantially without using a liquid medium.
The method of dry mixing is not particularly limited, but a method of physically mixing the powdery solid A and the powdery solid B so as to be as uniform as possible using a mixer for powder is preferable. A preferable bulk elemental composition of the thus obtained mixture is represented by the following formula (4). Mo _a P _b Cu _c V _d X _e Y _f O _g (4) In the formula (4), Mo, P, Cu, V and O represent molybdenum, phosphorus, copper, vanadium and oxygen, respectively, and X
Is at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, Y is iron, cobalt, nickel, zinc, magnesium, calcium,
Selected from the group consisting of strontium, barium, titanium, chromium, tungsten, manganese, silver, boron, silicon, tin, lead, arsenic, antimony, bismuth, niobium, tantalum, zirconium, indium, sulfur, selenium, tellurium, lanthanum and cerium. At least 1
Represents a seed element. However, a, b, c, d, e, f and g represent the atomic ratio of each element, and when a = 12, 0.1
≦ b ≦ 3, 0.01 ≦ c ≦ 3, 0.01 ≦ d ≦ 3, 0.
01 ≦ e ≦ 3, 0 ≦ f ≦ 3, and g is the atomic ratio of oxygen required to satisfy the atomic ratio of each component.

The dry mixture of solid A and solid B is then molded. The molding method is not particularly limited, and various molding methods such as tablet molding, extrusion molding and granulation can be used. During molding, the specific surface area of the molded product, the pore volume and the pore distribution is controlled with good reproducibility, for the purpose of increasing the mechanical strength, for example, barium sulfate, inorganic salts such as ammonium nitrate, lubricants such as graphite, Celluloses,
Additives and additives such as starch, polyvinyl alcohol, organic substances such as stearic acid, hydroxide sol such as silica sol and alumina sol, whiskers, inorganic fibers such as glass fibers and carbon fibers may be appropriately added. The shape of the molded product is not particularly limited, and examples thereof include a spherical shape, a cylindrical shape, a ring shape, and a plate shape.

The molded product thus obtained has a particle size of 300 to
It is baked at 500 ° C. The firing is usually performed under the flow of an oxygen-containing gas such as air and / or under the flow of an inert gas.
The firing time is not particularly limited, but is usually 0.5 hour or more, preferably 1 to 40 hours. The catalyst obtained by calcination preferably contains a structure of heteropolyacid or heteropolyacid salt.

The existence state of each component of the catalyst thus produced, especially the existence state of X, is not clear because it is complicated. However, since the solid A containing at least molybdenum, phosphorus and X and the solid B containing at least molybdenum and phosphorus and not containing X are dry mixed, the method described in JP-A-5-177141 is used. The structure of the catalyst produced, namely molybdenum,
The crystal particle surface of the heteropolyacid salt containing phosphorus and X
This is different from the structure covered with a heteropolyacid containing no.

Next, a method for producing methacrylic acid by vapor-phase catalytic oxidation of methacrolein with molecular oxygen using the catalyst of the present invention thus obtained will be described. The methacrolein concentration of the raw material gas used for the vapor phase catalytic oxidation can be varied within a wide range, but preferably 1 to
20% by volume, particularly preferably 3 to 10% by volume. The raw material methacrolein may contain a small amount of impurities such as water and lower saturated aldehydes that do not substantially affect the reaction, but the raw material gas contains such impurities derived from methacrolein. May be.

The source gas must contain molecular oxygen, but the amount of molecular oxygen in the source gas is preferably 0.4 to 4 times mol of methacrolein, particularly 0.5 to 3 times. Molar is preferred. It is industrially advantageous to use air as the molecular oxygen source of the raw material gas, but air enriched with pure oxygen can also be used if necessary. The raw material gas is preferably diluted with an inert gas such as nitrogen or carbon dioxide, or steam. The reaction pressure of the gas phase catalytic oxidation is from atmospheric pressure to several atmospheres. The reaction temperature is generally 200 to 450 ° C, preferably 250 to 400 ° C. The contact time between the raw material gas and the catalyst is usually 1 to 9 seconds, preferably 2 to 6 seconds.

[0018]

EXAMPLES The present invention will be described below with reference to examples and comparative examples. However, "parts" in Examples and Comparative Examples mean parts by weight. The reaction test analysis was performed by gas chromatography. The conversion of methacrolein as a raw material, the selectivity of methacrylic acid produced, and the yield are defined as follows. Methacrolein reaction rate (%) = (B / A) × 100 Methacrylic acid selectivity (%) = (C / B) × 100 Methacrylic acid yield (%) = (C / A) × 100 where A is The number of moles of methacrolein supplied, B is the number of moles of reacted methacrolein, and C is the number of moles of methacrylic acid produced.

Example 1 100 parts of ammonium paramolybdate, 4.4 parts of ammonium metavanadate and 14.4 parts of potassium nitrate were dissolved in 400 parts of pure water.
While stirring this, 8.2 parts of 85% phosphoric acid was added to pure water 10
Solution was added to 1 part, and 1.1 parts of copper nitrate was further added to 1 part of pure water.
A solution dissolved in 0 part was added. Then bismuth nitrate 6.9
After adding a uniform solution of bismuth nitrate containing 7.0 parts of 60% nitric acid and 40 parts of pure water to the above mixture, the temperature was raised to 95 ° C. To this was added a solution prepared by dissolving 2.2 parts of 60% arsenic acid in 10 parts of pure water, followed by 2.1 parts of antimony trioxide and 1.6 parts of cerium dioxide. The obtained aqueous slurry was evaporated to dryness with heating and stirring, dried at 130 ° C. for 16 hours, and then pulverized to obtain a powdery solid A-1. The composition of elements other than oxygen in the solid A-1 is Mo ₁₂ P _1.5 V _0.8 Cu _{0. 1} Sb
_{It was 0.3} Bi _0.3 As _0.2 Ce _0.2 K ₃ .

Separately, ammonium paramolybdate 10
0 part and 4.4 parts of ammonium metavanadate were dissolved in 400 parts of pure water. While stirring this, a solution prepared by dissolving 8.2 parts of 85% phosphoric acid in 10 parts of pure water was added, and further a solution prepared by dissolving 1.1 parts of copper nitrate in 10 parts of pure water was added. Next, a uniform solution of bismuth nitrate containing 7.0 parts of 60% nitric acid and 40 parts of pure water was added to 6.9 parts of bismuth nitrate, and the temperature was raised to 95 ° C. after the addition. 60% arsenic acid 2.
A solution prepared by dissolving 2 parts in 10 parts of pure water was added, followed by 2.1 parts of antimony trioxide and 1.6 parts of cerium dioxide. The obtained aqueous slurry was evaporated to dryness with heating and stirring, dried at 130 ° C. for 16 hours, and then pulverized to obtain a powdery solid B-1. This solid B
The composition of elements other than oxygen of -1 is Mo ₁₂ P _1.5 V
_0.8 Cu _0.1 Sb _0.3 Bi _{0 . 3} As _0.2 Ce
It was _0.2 .

Next, 28 parts of solid A-1 and 50 parts of solid B-1 were thoroughly mixed, and then 2.3 parts of graphite was added and further well mixed. This mixture was molded into a 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, and the obtained molded product was 380 ° C. under air flow.
A catalyst was prepared by calcining for 5 hours. The composition of the elements of this catalyst excluding oxygen is Mo ₁₂ P _1.5 V _0.8 Cu _0.1
It was Sb _0.3 Bi _0.3 As _0.2 Ce _0.2 K ₁ .

This catalyst was filled in a reaction tube, and a raw material gas consisting of 5% by volume of methacrolein, 10% by volume of oxygen, 30% by volume of steam and 55% by volume of nitrogen was passed through at a reaction temperature of 290 ° C. and a contact time of 3.6 seconds. As a result, the reaction rate of methacrolein was 91.5%, the selectivity of methacrylic acid was 88.9%, and the yield of methacrylic acid was 81.3%.

Example 2 100 parts of ammonium paramolybdate, 4.4 parts of ammonium metavanadate and 9.6 parts of potassium nitrate were dissolved in 400 parts of pure water. While stirring this, a solution prepared by dissolving 8.2 parts of 85% phosphoric acid in 10 parts of pure water was added, and further 1.1 parts of copper nitrate was added to 10 parts of pure water.
Part dissolved solution was added. Next, a uniform solution of bismuth nitrate containing 7.0 parts of 60% nitric acid and 40 parts of pure water was added to 6.9 parts of bismuth nitrate, and the temperature was raised to 95 ° C. after the addition. To this was added a solution prepared by dissolving 2.2 parts of 60% arsenic acid in 10 parts of pure water, followed by 2.1 parts of antimony trioxide and 1.6 parts of cerium dioxide. The resulting aqueous slurry was evaporated to dryness with heating and stirring, then at 1300C
The powdery solid A-2 was obtained by drying for 6 hours and then pulverizing. The composition of elements other than oxygen in the solid A-2 is Mo ₁₂ P _1.5 V _0.8 Cu _0.1 Sb.
_{It was 0.3} Bi _0.3 As _0.2 Ce _0.2 K ₂ .
Further, a powdery solid B-1 was obtained in the same manner as in Example 1.

Next, 50 parts of solid A-2 and 46 parts of solid B-1 were thoroughly mixed, and then 2.9 parts of graphite was added and further well mixed. This mixture was molded into a 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, and the obtained molded product was 380 ° C. under air flow.
A catalyst was prepared by calcining for 5 hours. The composition of the elements of this catalyst excluding oxygen is Mo ₁₂ P _1.5 V _0.8 Cu _0.1
It was Sb _0.3 Bi _0.3 As _0.2 Ce _0.2 K ₁ .

When a reaction was carried out in the same manner as in Example 1 using this catalyst, the reaction rate of methacrolein was 91.6%, the selectivity of methacrylic acid was 89.0%, and the yield of methacrylic acid was 81.5.
%Met.

Comparative Example 1 100 parts of ammonium paramolybdate, 4.4 parts of ammonium metavanadate and 4.8 parts of potassium nitrate were dissolved in 400 parts of pure water. While stirring this, a solution prepared by dissolving 8.2 parts of 85% phosphoric acid in 10 parts of pure water was added, and further 1.1 parts of copper nitrate was added to 10 parts of pure water.
Part dissolved solution was added. Next, a uniform solution of bismuth nitrate containing 7.0 parts of 60% nitric acid and 40 parts of pure water was added to 6.9 parts of bismuth nitrate, and the temperature was raised to 95 ° C. after the addition. To this was added a solution prepared by dissolving 2.2 parts of 60% arsenic acid in 10 parts of pure water, followed by 2.1 parts of antimony trioxide and 1.6 parts of cerium dioxide. The resulting aqueous slurry was evaporated to dryness with heating and stirring, then at 1300C
The powdery solid A-3 was obtained by drying for 6 hours and then pulverizing.

Next, 3 parts of graphite was added to 100 parts of the solid A-3 and mixed well. This mixture was molded into a 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, and the obtained molded product was 380 in an air stream.
A catalyst was produced by calcining at ℃ for 5 hours. The composition of elements other than oxygen in this catalyst was the same as Mo ₁₂ P in Examples 1 and 2.
_1.5 V _0.8 Cu _0.1 Sb _0.3 Bi _0.3 As
_{It was 0.2} Ce _0.2 K ₁ .

When a reaction was carried out in the same manner as in Example 1 using this catalyst, the reaction rate of methacrolein was 90.0%, the selectivity of methacrylic acid was 88.2%, and the yield of methacrylic acid was 79.4.
%Met.

Comparative Example 2 100 parts of ammonium paramolybdate, 4.4 parts of ammonium metavanadate and 2.4 parts of potassium nitrate were dissolved in 400 parts of pure water. While stirring this, a solution prepared by dissolving 8.2 parts of 85% phosphoric acid in 10 parts of pure water was added, and further 1.1 parts of copper nitrate was added to 10 parts of pure water.
Part dissolved solution was added. Next, a uniform solution of bismuth nitrate containing 7.0 parts of 60% nitric acid and 40 parts of pure water was added to 6.9 parts of bismuth nitrate, and the temperature was raised to 95 ° C. after the addition. To this was added a solution prepared by dissolving 2.2 parts of 60% arsenic acid in 10 parts of pure water, followed by 2.1 parts of antimony trioxide and 1.6 parts of cerium dioxide. The resulting aqueous slurry was evaporated to dryness with heating and stirring, then at 1300C
It was dried for 6 hours and then pulverized to obtain a powdery solid A-4. The composition of elements other than oxygen in the solid A-4 is Mo ₁₂ P _1.5 V _0.8 Cu _0.1 Sb.
_{It was 0.3} Bi _0.3 As _0.2 Ce _0.2 K _0.5 . Moreover, it carried out similarly to Example 1, and obtained solid A-1.

Next, 20 parts of solid A-1 and 109 parts of solid A-4 were thoroughly mixed, and then graphite 2.9 was used.
Parts were added and mixed well. This mixture was molded into a 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, and the obtained molded product was 380 in an air stream.
A catalyst was produced by calcining at ℃ for 5 hours. The composition of elements other than oxygen of this catalyst is Mo ₁₂ P _1.5 V _0.8 Cu.
_0.1 Sb _0.3 Bi _{0. 3} As _0.2 Ce _0.2 K ₁
Met.

When a reaction was carried out in the same manner as in Example 1 using this catalyst, the reaction rate of methacrolein was 90.3%, the selectivity of methacrylic acid was 88.5%, and the yield of methacrylic acid was 79.9.
%Met.

[Comparative Example 3] A suspension C was obtained by suspending 100 parts of the solid A-1 prepared in the same manner as in Example 1 in 200 parts of pure water at 80 ° C.

Separately, ammonium paramolybdate 10
0 part and 4.4 parts of ammonium metavanadate were dissolved in 400 parts of pure water. While stirring this, a solution prepared by dissolving 8.2 parts of 85% phosphoric acid in 10 parts of pure water was added, and further a solution prepared by dissolving 1.1 parts of copper nitrate in 10 parts of pure water was added. Next, a uniform solution of bismuth nitrate containing 7.0 parts of 60% nitric acid and 40 parts of pure water was added to 6.9 parts of bismuth nitrate, and the temperature was raised to 95 ° C. after the addition. 60% arsenic acid 2.
A solution prepared by dissolving 2 parts in 10 parts of pure water was added, followed by 2.1 parts of antimony trioxide and 1.6 parts of cerium dioxide. 203 parts of the above suspension C were added to the obtained aqueous slurry.
Were mixed and evaporated to dryness with heating and stirring, then at 130 ° C.
It was dried for 16 hours and then pulverized to obtain a powdery solid substance.

Next, 3 parts of graphite was added to 100 parts of the solid material and mixed well. This mixture was molded into a ring shape having an outer diameter of 5 mm, an inner diameter of 2 mm and a length of 5 mm by a tablet molding machine, and the obtained molded product was calcined at 380 ° C. for 5 hours under air flow to produce a catalyst. The composition of elements other than oxygen of this catalyst is Mo ₁₂ P _1.5 V _0.8 Cu _0.1 S
was _{b 0.3 Bi 0.3 As 0.2 Ce 0.2} K 1.

Using this catalyst, a reaction was carried out in the same manner as in Example 1. The reaction rate of methacrolein was 90.4%, the selectivity of methacrylic acid was 88.5%, and the yield of methacrylic acid was 80.0.
%Met.

[Example 3] Ammonium paramolybdate
100 parts of ammonium, 2.8 parts of ammonium metavanadate and
And 27.6 parts of cesium nitrate were dissolved in 400 parts of pure water.
While stirring this, 8.2 parts of 85% phosphoric acid was added to pure water 10
Add the dissolved solution to 100 parts and stir at 100 ° C for 30 minutes.
It was The resulting aqueous slurry by a co-current spray dryer,
Dryer inlet temperature 300 ℃, slurry spray turntable 200
Powdered solid by drying under the condition of 00 rpm
The product A-5 was obtained. This solid A-5 contains elements other than oxygen.
The composition is Mo₁₂P_1.5V_0.5Cu_0.3Fe
_0.4Mg_0.15Zn_0.1Cs _ThreeMet.

Separately, ammonium paramolybdate 10
0 part and 2.8 parts of ammonium metavanadate were dissolved in 400 parts of pure water. While stirring this, a solution in which 8.2 parts of 85% phosphoric acid was dissolved in 10 parts of pure water was added, and the temperature was raised to 95 ° C while stirring. Then, a solution prepared by dissolving 5.1 parts of copper nitrate, 11.4 parts of ferric nitrate, 2.1 parts of zinc nitrate and 2.7 parts of magnesium nitrate in 120 parts of pure water was added. Furthermore, this mixed solution was stirred at 100 ° C. for 30 minutes. The obtained aqueous slurry is dried by a co-current type spray dryer under the conditions of a dryer inlet temperature of 300 ° C. and a slurry spray rotating disc of 20000 revolutions / minute to obtain a powdery solid B-
Got 2. The composition of elements other than oxygen in the solid B-2 is Mo ₁₂ P _1.5 V _0.5 Cu _0.3 Fe _0.4 M.
It was g _0.15 Zn _0.1 .

Next, 30 parts of solid A-5 and 50 parts of solid B-2 were thoroughly mixed, and then 2.4 parts of graphite was added and further well mixed. This mixture was molded into a ring shape having an outer diameter of 5 mm, an inner diameter of 2 mm and a length of 3 mm by a tablet molding machine, and the obtained molded product was 380 ° C. under air circulation.
A catalyst was prepared by calcining for 5 hours. The composition of elements of this catalyst excluding oxygen is Mo ₁₂ P _1.5 V _0.5 Cu _0.3.
Was _{Fe 0.4 Mg 0.1 5 Zn 0.1 Cs} 1.

When a reaction was carried out in the same manner as in Example 1 using this catalyst, the reaction rate of methacrolein was 88.9%, the selectivity of methacrylic acid was 86.6%, and the yield of methacrylic acid was 77.0.
%Met.

Comparative Example 4 100 parts of ammonium paramolybdate, 2.8 parts of ammonium metavanadate and 9.2 parts of cesium nitrate were dissolved in 400 parts of pure water. While stirring this, a solution in which 8.2 parts of 85% phosphoric acid was dissolved in 10 parts of pure water was added, and the temperature was raised to 95 ° C while stirring. Next, 3.4 parts of copper nitrate, 7.6 parts of ferric nitrate, 1.4 parts of zinc nitrate and 1.8 parts of magnesium nitrate were added to pure water 8 parts.
A solution dissolved in 0 part was added. Add 100 parts of this mixture.
The mixture was stirred at 0 ° C for 30 minutes. The obtained aqueous slurry was dried with a co-current spray dryer under the conditions of a dryer inlet temperature of 300 ° C. and a slurry spray rotating disk of 20000 rpm to obtain a powdery solid A-6.

Next, 3 parts of graphite was added to 100 parts of the solid A-6 and mixed well. This mixture was molded into a ring shape having an outer diameter of 5 mm, an inner diameter of 2 mm and a length of 3 mm with a tablet molding machine, and the obtained molded product was 380 in an air stream.
A catalyst was produced by calcining at ℃ for 5 hours. The composition of elements of this catalyst excluding oxygen is Mo ₁₂ P _1.5 V _0.5 Cu _{0.
． It was 3} Fe _0.4 Mg _0.15 Zn _0.1 Cs ₁ .

When a reaction was carried out in the same manner as in Example 1 using this catalyst, the reaction rate of methacrolein was 87.4%, the selectivity of methacrylic acid was 85.8%, and the yield of methacrylic acid was 75.0.
%Met.

[0043]

According to the present invention, it is possible to produce a catalyst for methacrylic acid synthesis which is excellent in activity and selectivity to methacrylic acid.

Continued front page    F term (reference) 4G069 AA02 AA08 BB06A BB06B                       BC03A BC03B BC05A BC06A                       BC06B BC09A BC10A BC10B                       BC12A BC13A BC18A BC19A                       BC21A BC22A BC25A BC25B                       BC26A BC26B BC27A BC27B                       BC31A BC31B BC32A BC35A                       BC35B BC42A BC43A BC43B                       BC50A BC51A BC54A BC54B                       BC55A BC56A BC58A BC59A                       BC59B BC60A BC62A BC66A                       BC66B BC67A BC68A BD03A                       BD05A BD07A BD07B BD08A                       BD09A BD10A CB17 EA04Y                       EB08 EB18Y FB07 FB30                       FC07 FC08                 4H006 AA02 AC46 BA01 BA04 BA05                       BA09 BA12 BA14 BA30 BA35                       BA81 BE30                 4H039 CA65 CC30

Claims (5)

[Claims] 1. At least molybdenum, phosphorus and X
(X represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium.) And a solid B containing at least molybdenum and phosphorus and not containing X are dry-mixed. After that, it is molded, and the molded product obtained is calcined at 300 to 500 ° C. to produce a catalyst for methacrylic acid synthesis. 2. The method for producing a catalyst for methacrylic acid synthesis according to claim 1, wherein the solid A is obtained by drying an aqueous slurry containing at least molybdenum, phosphorus and X. 3. The catalyst for methacrylic acid synthesis according to claim 1 or 2, wherein the solid B is obtained by drying an aqueous slurry containing at least molybdenum and phosphorus and not containing X. Production method. 4. The method for producing a catalyst for methacrylic acid synthesis according to claim 1, wherein the atomic ratio of molybdenum to X contained in the solid A is 12: 1.5 to 12: 4. . 5. The catalyst for methacrylic acid synthesis obtained by calcination is a composite oxide represented by the formula (1).
5. A method for producing the catalyst for methacrylic acid synthesis according to any one of 5 to 6. Mo _a P _b Cu _c V _d X _e Y _f O _g (1) (wherein Mo, P, Cu, V and O represent molybdenum, phosphorus, copper, vanadium and oxygen, respectively, and X represents potassium, rubidium, At least one element selected from the group consisting of cesium and thallium, Y is iron, cobalt, nickel, zinc, magnesium, calcium, strontium, barium, titanium, chromium, tungsten, manganese, silver, boron, silicon, tin, Lead, arsenic,
It represents at least one element selected from the group consisting of antimony, bismuth, niobium, tantalum, zirconium, indium, sulfur, selenium, tellurium, lanthanum and cerium. However, a, b, c, d, e, f and g
Represents the atomic ratio of each element, and when a = 12, 0.1 ≦ b
≦ 3, 0.01 ≦ c ≦ 3, 0.01 ≦ d ≦ 3, 0.01
≦ e ≦ 3, 0 ≦ f ≦ 3, and g is the atomic ratio of oxygen required to satisfy the atomic ratio of each component. )