JP3347246B2 - Method for producing catalyst for the synthesis of unsaturated aldehydes and unsaturated carboxylic acids - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to propylene, isobutylene, tertiary butyl alcohol (hereinafter abbreviated as TBA) or methyl tertiary butyl ether (hereinafter M).
Abbreviated as TBE. The present invention relates to a method for producing a catalyst used for synthesizing the corresponding unsaturated aldehyde and unsaturated carboxylic acid by gas-phase catalytic oxidation of the above) using molecular oxygen.

[0002]

2. Description of the Related Art Conventionally, a catalyst used for producing acrolein and acrylic acid by gas-phase catalytic oxidation of propylene, and a catalyst used for producing methacrolein and methacrylic acid by gas-phase catalytic oxidation of isobutylene, TBA or MTBE. Numerous proposals have been made for catalysts used for the above and methods for producing such catalysts. For example, in order to improve catalyst performance, a method of adding an organic compound such as aniline, methylamine, pentaerythritol or the like at the time of catalyst preparation for the purpose of controlling catalyst pores is disclosed in JP-A-58-98143 and JP-A-398143. It is disclosed in JP-A-109946.

[0003] Since these compounds remove the organic compound added when the catalyst is heat-treated, there is an advantage that the pore size of the catalyst can be freely controlled by changing the size of the organic compound used. However, sintering of the catalyst by combustion of the organic compound and reduction of the catalyst by the organic compound occur at the heat treatment stage, so that the heat treatment as the catalyst activation treatment becomes complicated and the reproducibility of the catalyst production is poor. have. Also, a method of adding starch is disclosed in JP-A-63-315.
147, JP-A-4-4048 and the like. As these examples show, there is currently a need for the development of an easy, reproducible and simple catalyst production method that freely controls the catalyst pore distribution, that is, improves the catalyst performance. It is.

[0004]

SUMMARY OF THE INVENTION The present invention is to provide a gas phase catalytic oxidation of propylene, isobutylene, TBA or MTBE using molecular oxygen to thereby obtain the corresponding unsaturated aldehyde and unsaturated carboxylic acid. An object of the present invention is to provide a simple and easy method for producing a catalyst.

[0005]

Means for Solving the Problems In order to maximize the catalyst performance, the present inventors have studied the possibility of controlling the catalyst pore distribution without adding an organic substance as in the prior art. As a result of intensive research, they found a technology that can control the pore distribution of the molded body by controlling the particle size distribution and shape of the raw material powder used in the wet shaping method of the catalyst,
Furthermore, they found a method for producing a catalyst having a more effective pore structure in a catalytic reaction by using hollow spherical particles in the course of the research, and completed the present invention.

That is, the present invention provides at least molybdenum, which is used when propylene, isobutylene, TBA or MTBE is subjected to gas phase catalytic oxidation using molecular oxygen to synthesize the corresponding unsaturated aldehyde and unsaturated carboxylic acid, respectively. In a method for producing a catalyst containing bismuth and iron, a mixed solution or an aqueous slurry containing a catalyst component is dried into hollow spherical particles having an average particle diameter of 1 to 250 μm using a spray dryer, and then calcined, and the obtained spherical particles are dried. After extruding the calcined powder with water and / or alcohol,
A method for producing a catalyst for synthesizing unsaturated aldehydes and unsaturated carboxylic acids, comprising drying and heat-treating or heat-treating.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a mixed solution or an aqueous slurry containing a catalyst component is prepared, dried using a spray drier into hollow spherical particles having an average particle diameter of 1 to 250 μm, and then calcined. After adding the water and / or alcohol to the obtained spherical particle fired powder and extruding it, drying and heat treatment,
Alternatively, the heat treatment is required.

The hollow spherical particles used in the present invention have an average particle size of 1 to 250 μm, preferably 5 to 220 μm, and particularly preferably 10 to 20 μm.
The range is 0 μm. The average particle diameter of the hollow spherical particles is 1
If it is less than μm, an appropriate pore size required for the oxidation reaction by the catalyst of the present invention cannot be obtained, and the yield of the reaction target product is significantly reduced. Conversely, when the average particle diameter of the hollow spherical particles exceeds 250 μm, the number of contact points between the spherical particles per unit volume decreases, and the mechanical strength of the molded catalyst decreases, which is not practical.

In the spray drying method employed in the present invention, when a mixed solution or an aqueous slurry containing a catalyst component is sprayed and discharged into hot air, droplets are easily formed into spheres due to surface tension. The spraying method includes a rotating disk type and a pressure type nozzle type. This spherical droplet has several hundreds
The drying period in hot air of ° C. is on the order of seconds. This instantaneous drying process also has a constant-rate drying period in which free water on the surface evaporates and a reduced-rate drying period in which internal moisture evaporates. In the constant-rate drying period, the surface dries instantaneously, whereas in the reduced-rate drying period, the water inside evaporates at a stretch after the constant-rate drying period, resulting in hollow spherical particles.

Therefore, in order to obtain hollow spherical particles,
Since it is necessary to go through each of the constant rate drying period and the decreasing rate drying period, an appropriate spray condition and drying temperature are selected and the operation is performed. In the present invention, a rotating disk method is employed as a method for producing hollow spherical particles. In the rotating disk method, the residence time of the sprayed droplets is very short compared to the pressure type nozzle method, and the hollow disk is used because a mechanism that passes the constant rate drying period described above and then the reduced rate drying period is used. A spherical dry powder is obtained. In order to prepare the hollow spherical dry particles using the spray drying method, for example, see “Ceramic Manufacturing Process-Preparation and Molding of Powder-” edited by The Ceramic Society of Japan, p. 3
7, edited by Kagaku Kogyo Co., Ltd. Separate volume Chemical Industry 34-2 New Supplementary Edition 2 "Drying" Industrial Operation Series No. 2 p. It can be obtained by drying conditions as shown at 99.

In the present invention, not only the voids between the spherical particles but also the hollow spherical particles obtained by the spray drying method are subjected to wet molding without destroying the hollow particles. By utilizing the pores of the hollow particles, a catalyst having better catalytic performance can be obtained.

The hollow spherical particles obtained by the spray drying method are then fired. 200 to 50 as firing temperature
A range of 0 ° C. is appropriate. Water and / or alcohol are added to the obtained calcined powder of the catalyst spherical particles, kneaded, and then wet shaping is performed. In kneading, an organic binder such as gelatin, cellulose, methylcellulose, ethylcellulose, hydroxypropylcellulose and the like can be added in addition to water and / or alcohol. It is also possible to further add diatomaceous earth, silica sol, silica gel, bentonite, kaolin, etc. as a shaping reinforcing agent, as well as glass fibers, asbestos, ceramic fibers, carbon fibers and the like.

As the shaping method, there are generally known extrusion molding, rounding, rolling granulation, supporting and the like. Extrusion molding can be performed into an arbitrary shape such as a ring shape, a column shape, and a star shape.

Next, the wet molded product is dried. As the drying method, it is also possible to use a method of drying in a dryer, but preferably a drying method of matching the drying speed of the inside and the outer surface of the shaped body using a humidity drying method or a microwave or the like It is valid. Further, it is also possible to perform a preliminary drying using a humidity drying method or a microwave or the like, followed by a main drying using a dryer or the like.

[0015] The shaped catalyst thus obtained is 300
Heat treatment is performed again at a temperature in the range of ６650 ° C. to use as a catalyst. Note that heat treatment may be performed without the drying step.

[0016] The present invention relates to compounds of the general formula _{Mo a Bi b Fe c A d} X e Y f Z g Si h O i ( respectively in Mo, Bi, Fe, Si and O wherein molybdenum, bismuth, iron, silicon and oxygen A is at least one selected from the group consisting of cobalt and nickel.
X represents at least one element selected from the group consisting of chromium, lead, manganese, calcium, magnesium, niobium, silver, barium, tin, tantalum and zinc; Y represents phosphorus, boron, Sulfur, selenium, tellurium,
Z represents at least one element selected from the group consisting of cerium, tungsten, antimony and titanium, and Z represents at least one element selected from the group consisting of lithium, sodium, potassium, rubidium, cesium and thallium. a, b, c, d, e, f, g, h and i represent the atomic ratio of each element, and when a = 12, b = 0.01
-3, c = 0.01-5, d = 1-12, e = 0-8,
f = 0 to 5, g = 0.001 to 2, h = 0 to 20, and i is the number of oxygen atoms necessary to satisfy the valence of each component. ) Can be preferably used for the catalyst having the composition represented by the formula (1).

The method for producing the catalyst powder used in the present invention does not need to be limited to a special method. Unless a significant uneven distribution of components is involved, well-known precipitation methods and oxide mixing methods are conventionally used. And various other methods can be used.

As the raw material of the catalyst component, oxides, sulfates, nitrates, carbonates, hydroxides, ammonium salts, halides and the like of each element can be used in combination. For example, as a molybdenum raw material, ammonium paramolybdate, molybdenum trioxide and the like can be used.

To synthesize unsaturated aldehydes and unsaturated carboxylic acids using the catalyst obtained in the present invention, molecular oxygen is added to propylene, isobutylene, TBA or MTBE as a raw material, and gaseous oxygen is added in the presence of the catalyst. Perform phase contact oxidation. The molar ratio of propylene, isobutylene, TBA or MTBE to oxygen is preferably from 1: 0.5 to 3. The source gas is preferably diluted with an inert gas for use. Although it is economical to use air as the oxygen source, air enriched with pure oxygen can be used if necessary. The reaction pressure is preferably from normal pressure to several atmospheres. The reaction temperature can be selected in the range of 200 to 450 ° C, but is particularly preferably in the range of 250 to 400 ° C.

[0020]

EXAMPLES Hereinafter, a method for producing a catalyst according to the present invention and a reaction example using the obtained catalyst will be specifically described. In the description, the conversion of the starting olefin, TBA or MTBE, and the selectivity of the unsaturated aldehyde and unsaturated carboxylic acid to be formed are defined as follows. In the description, “parts” means parts by weight. The analysis was based on gas chromatography.

[0021]

(Equation 1)

[0022]

(Equation 2)

[0023]

(Equation 3)

[Example 1] 500 parts of ammonium paramolybdate, 6.2 parts of ammonium paratungstate and 1.4 parts of potassium nitrate were added to 1000 parts of water and heated and stirred (Solution A). Separately, 60 parts nitric acid 41.9 in 600 parts of water
Then, 103.0 parts of bismuth nitrate was added and dissolved. To this, 95.3 parts of ferric nitrate, 398.3 parts of cobalt nitrate and 35.1 parts of zinc nitrate were sequentially added, and 400 parts of water was further added to dissolve (solution B).

After adding Liquid B to Liquid A to form an aqueous slurry,
Add 20.6 parts of antimony trioxide and heat and stir.
RO JAPAN "Spray Dryer (Drying Chamber SD-1
2.5 type, sprayer rotating disk wheel model SL-24-1
20), the rotating disk is rotated at 22,000 rpm, and the slurry previously prepared so that the inlet temperature is 450 ° C. and the outlet temperature is 150 ° C. is supplied, and the average particle diameter is 75.3.
μm hollow spherical particles were obtained. The obtained hollow spherical particles were subjected to a rotary kiln at 300 ° C. in an air atmosphere for 1 hour.
Heat treatment was performed for a time to obtain a fired catalyst powder.

15 parts of methylcellulose and 150 parts of water were added to 500 parts of the calcined powder of the catalyst, mixed and kneaded, and the mixture was kneaded with a piston extruder to form a cylindrical cylinder having an outer diameter of 6 mm, an inner diameter of 3 mm and a length of 5 mm. Was extruded. The extruded catalyst was dried at 105 ° C. for 2 hours. The obtained dry molded catalyst was subjected to a heat treatment at 530 ° C. for 3 hours in an air atmosphere. The composition of the elements other than oxygen (the same applies hereinafter) in the catalyst molded body thus obtained was as follows. Mo ₁₂ W _0.1 Bi _0.9 Fe _1.0 Sb _0.6 Co _5.8 Zn
_0.5 K _0.06

The molded catalyst is filled in a stainless steel reaction tube, and a raw material mixture gas of propylene 5%, oxygen 12%, steam 10% and nitrogen 73% (vol%) passes through the catalyst layer in a contact time of 3.6 seconds. And reacted at 310 ° C. As a result, the conversion of propylene was 99.3%, the selectivity of acrolein was 90.1%, and the selectivity of acrylic acid was 6.9%. In addition, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that the hollow spherical particles maintained a spherical shape.

[Embodiment 2] In Embodiment 1, "NIR
O Japan "spray dryer (drying chamber SD-4.
0 type, sprayer rotary disk wheel type FU-11 type), the rotary disk is rotated at 18,000 rpm, and the slurry previously prepared so that the inlet temperature is 450 ° C. and the outlet temperature is 150 ° C. Sintering, molding, and the like were performed in the same manner as in Example 1, except that hollow spherical particles having an average particle size of 8.8 μm were obtained by feeding.
Drying, heat treatment and reaction were performed. As a result, the conversion of propylene was 99.3% and the selectivity of acrolein was 90.3%.
% And selectivity for acrylic acid was 6.8%. In addition, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that although the hollow spherical particles were extremely partially broken, the hollow spherical particles generally maintained a spherical shape.

[Embodiment 3] In Embodiment 1, "NIR
O JAPAN "Spray dryer (drying chamber SD-2)
5.0 type, sprayer rotating disk wheel model SL-24-1
20), the rotating disk is rotated at 18,000 rpm, and the slurry previously prepared so that the inlet temperature is 450 ° C. and the outlet temperature is 150 ° C. is supplied, and the average particle size is 195.
Baking, molding, drying, heat treatment and reaction were carried out in the same manner as in Example 1 except that 6 μm hollow spherical particles were obtained. As a result, the conversion of propylene was 99.0%, the selectivity of acrolein was 90.5%, and the selectivity of acrylic acid was 6.9%. In addition, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that the hollow spherical particles maintained a spherical shape.

Comparative Example 1 In Example 1, "NIR
O Japan "spray dryer (drying chamber SD-4.
0 type, sprayer rotary disk wheel type FU-11 type), the rotary disk was rotated at 24,000 rpm, and the slurry previously prepared so that the inlet temperature was 450 ° C and the outlet temperature was 150 ° C. Sintering, molding, drying, heat treatment and reaction were carried out in the same manner as in Example 1 except that hollow spherical particles having an average particle size of 0.55 μm were obtained by feeding. As a result, the conversion of propylene was 98.9% and the selectivity of acrolein was 88.9%.
The selectivity of acrylic acid was 6.8%. Also, as a result of observing the inside of the molded catalyst with a scanning electron microscope,
Although the hollow spherical particles were slightly broken, it was confirmed that the hollow spherical particles generally maintained a spherical shape.

Comparative Example 2 In Example 1, "NIR
O Japan "spray dryer (drying chamber SD-4.
0 type, sprayer counter-current type two-fluid nozzle), the tip of the sprayer counter-current type two-fluid nozzle was adjusted and the inlet temperature was 400 ° C.
Sintering, molding, drying, heat treatment and reaction were carried out in the same manner as in Example 1 except that the slurry prepared above was supplied so that the outlet temperature became 150 ° C., and spherical particles having an average particle size of 48.5 μm were obtained. Was done. As a result, the conversion of propylene was 98.
The selectivity of acrolein was 79.0%, and the selectivity of acrylic acid was 6.5%. Further, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that the real dense spherical particles maintained a spherical shape.

Comparative Example 3 In Example 1, "NIR
O JAPAN "Spray dryer (drying chamber SD-1)
Using a 2.5-type two-fluid nozzle with a counter-current sprayer, the tip of the two-fluid nozzle with a counter-current sprayer was adjusted and the inlet temperature was adjusted to 400.
Sintering, molding, drying and heat treatment in the same manner as in Example 1 except that the slurry previously prepared so as to have an outlet temperature of 150 ° C. was supplied to obtain dense spherical particles having an average particle size of 168.1 μm. And the reaction was performed. As a result, the conversion of propylene was 98.8%, the selectivity of acrolein was 89.2%, and the selectivity of acrylic acid was 6.4%. Further, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that the real dense spherical particles maintained a spherical shape.

Example 4 60% nitric acid 42 in 400 parts of water
Then, 68.7 parts of bismuth nitrate was added and dissolved. To this, 102.9 parts of nickel nitrate and 24.1 parts of antimony trioxide were sequentially added and dissolved and dispersed. 165 parts of 28% aqueous ammonia was added to this mixture to obtain a white precipitate and a blue solution. This was heated and stirred, and most of the water was evaporated. The obtained slurry-like substance is
After drying at 750 ° C for 16 hours, heat-treating at 750 ° C for 2 hours,
Finely ground. 11. 500 parts of ammonium paramolybdate and ammonium paratungstate in 1000 parts of water
3 parts and 23.0 parts of cesium nitrate were added, and the mixture was heated and stirred (Solution A).

Separately, ferric nitrate (190.7) was added to 700 parts of water.
Parts, 377.7 parts of cobalt nitrate and magnesium nitrate 4
8.4 parts were sequentially added and dissolved (Solution B). Solution B was added to Solution A to form a slurry, and then 425.5 parts of 20% silica sol and fine powder of the above bismuth-nickel-antimony compound were added thereto, followed by heating and stirring, and a spray dryer (manufactured by NIRO JAPAN) (drying chamber SD -12.5 type, using a sprayer rotating disk wheel model SL-24-120), rotating the rotating disk at 23,000 rpm, the inlet temperature 450
C. and the slurry previously prepared at an outlet temperature of 150 ° C. were supplied to obtain hollow spherical particles having an average particle size of 51.3 μm. The hollow spherical particles were heat-treated at 300 ° C. for 1 hour in an air atmosphere using a rotary kiln to obtain a fired catalyst powder.

15 parts of hydroxypropylcellulose and 150 parts of water are added to 500 parts of the calcined powder of the catalyst, mixed and kneaded. Extrusion molding was performed. The extruded catalyst was dried at 105 ° C. for 2 hours using a dryer. The obtained dried molded catalyst was placed in an air atmosphere 5
Heat treatment was performed at 20 ° C. for 3 hours. The composition of the elements of the obtained molded catalyst was as follows. Mo ₁₂ W _0.2 Bi _0.6 Fe _2.0 Sb _0.7 Ni _1.5 Co
_5.5 Mg _0.8 Cs _0.5 Si _6.0

The molded catalyst is filled in a stainless steel reaction tube, and a raw material mixed gas of 5% isobutylene, 12% oxygen, 10% steam and 73% (volume%) of nitrogen is contacted for 3.6 times.
After passing through the catalyst layer in seconds, the reaction was carried out at 350 ° C. As a result, the conversion of isobutylene was 98.0%, the selectivity of methacrolein was 89.8%, and the selectivity of methacrylic acid was 4.2%. In addition, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that the hollow spherical particles maintained a spherical shape.

[Embodiment 5] In Embodiment 4, "NIR
O Japan "spray dryer (drying chamber SD-4.
0 type, sprayer rotary disk wheel type FU-11 type), the rotary disk is rotated at 18,000 rpm, and the slurry previously prepared so that the inlet temperature is 450 ° C. and the outlet temperature is 150 ° C. Sintering, molding, drying, heat treatment and reaction were carried out in the same manner as in Example 4 except that hollow spherical particles having an average particle diameter of 10.9 μm were obtained by feeding. As a result, the conversion of isobutylene was 98.2% and the selectivity of methacrolein was 8
9.9% and a selectivity of methacrylic acid of 4.0%. In addition, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that although the hollow spherical particles were extremely partially broken, the hollow spherical particles generally maintained a spherical shape.

[Embodiment 6] In Embodiment 4, "NIR
O JAPAN "Spray dryer (drying chamber SD-2)
5.0 type, sprayer rotating disk wheel model SL-24-1
20), the rotating disk is rotated at 19,000 rpm, and the slurry previously prepared so that the inlet temperature is 450 ° C. and the outlet temperature is 150 ° C. is supplied, and the average particle size is 168.
Except for obtaining hollow spherical particles of 5 μm, firing, molding, drying, heat treatment and reaction were carried out in the same manner as in Example 4. As a result, the conversion of isobutylene was 98.0%, the selectivity of methacrolein was 90.1%, and the selectivity of methacrylic acid was 3.9%. In addition, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that the hollow spherical particles maintained a spherical shape.

Comparative Example 4 In Example 4, “NIR
O Japan "spray dryer (drying chamber SD-4.
0 type, sprayer rotary disk wheel type FU-11 type), the rotary disk was rotated at 24,000 rpm, and the slurry previously prepared so that the inlet temperature was 450 ° C and the outlet temperature was 150 ° C. Sintering, molding, drying, heat treatment and reaction were carried out in the same manner as in Example 4, except that hollow spherical particles having an average particle diameter of 0.43 μm were obtained by feeding. As a result, the conversion of isobutylene was 98.5% and the selectivity of methacrolein was 8
The selectivity of 9.1% and methacrylic acid was 3.6%. In addition, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that although the hollow spherical particles were somewhat broken, the hollow spherical particles generally maintained a spherical shape.

[Comparative Example 5] In Example 4, “NIR
O Japan "spray dryer (drying chamber SD-4.
0 type, sprayer counter-current type two-fluid nozzle), the tip of the sprayer counter-current type two-fluid nozzle was adjusted and the inlet temperature was 400 ° C.
Sintering, molding, drying, heat treatment and reaction were carried out in the same manner as in Example 4 except that the previously prepared slurry was supplied at an outlet temperature of 150 ° C. to obtain dense spherical particles having an average particle diameter of 66.0 μm. Was done. As a result, the conversion of isobutylene was 9
The selectivity for methacrolein was 7.5%, and the selectivity for methacrylic acid was 3.4%. Further, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that the real dense spherical particles maintained a spherical shape.

Comparative Example 6 In Example 4, “NIR
O JAPAN "Spray dryer (drying chamber SD-1)
Using a 2.5-type two-fluid nozzle with a counter-current sprayer, the tip of the two-fluid nozzle with a counter-current sprayer was adjusted and the inlet temperature was adjusted to 400.
℃, the same temperature as in Example 4, except that the slurry prepared above was supplied at 150 ° C. and the outlet temperature was 150 ° C. to obtain dense spherical particles having an average particle size of 175.5 μm. And the reaction was performed. As a result, the conversion of isobutylene was 97.5%, the selectivity of methacrolein was 89.2%, and the selectivity of methacrylic acid was 3.5%. Further, as a result of observing the inside of the molded catalyst with a scanning electron microscope, it was confirmed that the real dense spherical particles maintained a spherical shape.

Example 7 A reaction was carried out in the same manner as in Example 4 except that the catalyst of Example 4 was used and the raw material was changed to TBA. As a result, the conversion of TBA was 100%, the selectivity of isobutylene was 1.7%, and the selectivity of methacrolein was 87.7.
% And methacrylic acid selectivity was 2.7%.

Example 8 A reaction was carried out in the same manner as in Example 4 except that the catalyst of Example 4 was used and the raw material was changed to MTBE. As a result, the reaction rate of MTBE was 100%, the selectivity of isobutylene was 2.0%, and the selectivity of methacrolein was 8%.
It was 7.9% and the selectivity of methacrylic acid was 2.6%.

[0044]

According to the present invention, a mixed solution or a slurry containing a catalyst component is prepared by using a spray drier to obtain an average particle size of 1-2.
By using hollow spherical particles of 50 μm and utilizing the voids between the spherical particles, effective pores for the oxidation reaction can be developed. That is, pores are further secured by using hollow spherical particles. Further, as an advantage of using hollow spherical particles, compared with the case of using real dense spherical particles, the number of pores per unit volume is further increased, so that the oxidation reaction yield is improved. Further, by molding while maintaining the hollow spherical particles, a connection hole is provided, and an optimum pore diameter is obtained, thereby improving the yield of the oxidation reaction.

Further, in the present invention, the conventional method of adding a pore-forming agent causes problems such as complicated heat treatment for removing various pore-forming agents. In the method using pores between hollow spherical particles having an average particle diameter of 1 to 250 μm for pore development, there is no need to remove a pore developing agent or the like, and a catalyst molded body with good reproducibility can be obtained by simple means. can get.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C07C 47/22 C07C 47/22 J 57/05 57/05 57/055 57/055 A B // C07B 61/00 300 C07B 61 / 00 300 (56) References JP-A-3-109946 (JP, A) JP-A-5-277381 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 23/88 C07C 45/32 C07C 47/22 C07C 57/04

Claims (1)

(57) [Claims] 1. A method for producing a corresponding unsaturated aldehyde and unsaturated carboxylic acid by subjecting propylene, isobutylene, tertiary butyl alcohol or methyl tertiary butyl ether to gas-phase catalytic oxidation using molecular oxygen. In a method for producing a catalyst containing at least molybdenum, bismuth and iron to be used, a mixed solution or an aqueous slurry containing a catalyst component is spray-dried to have an average particle diameter of 1 to 25.
An unsaturated aldehyde, which is dried to 0 μm hollow spherical particles, fired, and the resulting fired spherical particle powder is extruded by adding water and / or alcohol, followed by drying and heat treatment or heat treatment. And a process for producing a catalyst for the synthesis of unsaturated carboxylic acids.