JP3446403B2 - Method for producing catalyst for synthesis of unsaturated aldehyde and unsaturated carboxylic acid - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a catalyst for synthesizing unsaturated aldehydes and unsaturated carboxylic acids. More specifically, the present invention relates to a method for producing a complex oxide catalyst used when vapor-phase catalytic oxidation of propylene or isobutylene with molecular oxygen to produce acrolein and acrylic acid or methacrolein and methacrylic acid.

[0002]

2. Description of the Related Art Many proposals have hitherto been made for catalysts for synthesizing acrolein and acrylic acid or methacrolein and methacrylic acid by subjecting propylene and isobutylene to catalytic oxidation with molecular oxygen. Further, the catalyst performance changes depending on the manufacturing method, and many methods for manufacturing a catalyst have been proposed. Among them, so-called salt decomposition in which a dried product containing a catalyst component is heated to desorb ammonium salts such as ammonium nitrate is disclosed in JP-A-5-253.
No. 480, the bed height of the dried product containing the catalyst component is 20 m.
There is disclosed a method in which it is installed so as to have a length of m or more.

[0003]

However, in the method described in Japanese Patent Application Laid-Open No. 5-253480, when the dried product is subjected to salt decomposition, the dried product is laminated in an appropriate container installed in a heating furnace. Therefore, it is considered that desorption of the ammonium salt from the catalyst surface is insufficient during the temperature rise process of the dried product, and the liquefied ammonium salt remaining causes the elution of the catalyst component. The properties are likely to vary, and the catalyst performance is not always sufficient.

Therefore, an object of the present invention is to provide a method for producing a high performance composite oxide catalyst used in the catalytic oxidation reaction of propylene and isobutylene. As a result of intensive studies, a mixed solution containing a catalyst component or The aqueous slurry is concentrated to dryness, and the obtained dried product is gradually added to a circulating gas kept at a temperature in the range of 200 to 450 ° C. for salt decomposition to obtain a higher temperature than conventional catalysts. The inventors have found that a catalyst with high performance can be obtained, and completed the present invention.

[0005]

That is, according to the present invention, the general formula Mo _a Bi _b Fe _{c Ad} B _e C _f D _g O _x (wherein Mo, Bi and Fe are molybdenum,
Represents bismuth and iron, A represents nickel and / or cobalt, B represents at least one element selected from the group consisting of manganese, zinc, calcium, magnesium, tin and lead, C represents phosphorus, boron, Ar represents at least one element selected from the group consisting of tellurium, tungsten, antimony and silicon, D represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, and a = When 12 is set, 0 <b ≦ 10, 0 <c ≦ 10, 1 ≦ d ≦ 1
0, 0 ≦ e ≦ 10, 0 ≦ f ≦ 10, 0 <g ≦ 2,
x is a value determined by the oxidation state of each element. ) In the process for producing a catalyst for synthesizing a corresponding unsaturated aldehyde and unsaturated carboxylic acid by vapor-phase catalytic oxidation of propylene or isobutylene represented by the formula (3) , a mixed solution containing a catalyst component or solidified the aqueous slurry concentrated to dryness, the dried product containing an ammonium salt obtained was kept at a predetermined temperature in the range of 200 to 450 ° C. line
At a standard speed of 0.01 to 2 m / sec into the flowing gas , 0.1 to 10 kg / min · m with respect to the gas flowing surface
It is a method for producing a catalyst characterized by adding ammonium at a rate of ² to remove ammonium salt , and then calcining.

The composition of the catalyst produced by the present invention has a general formula of Mo _a Bi _b Fe _c A _d B _e C _f D _g O _x (wherein Mo, Bi and Fe are molybdenum,
Represents bismuth and iron, A represents nickel and / or cobalt, B represents at least one element selected from the group consisting of manganese, zinc, calcium, magnesium, tin and lead, C represents phosphorus, boron, Ar represents at least one element selected from the group consisting of tellurium, tungsten, antimony and silicon, D represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, and a = When 12 is set, 0 <b ≦ 10, 0 <c ≦ 10, 1 ≦ d ≦ 1
0, 0 ≦ e ≦ 10, 0 ≦ f ≦ 10, 0 <g ≦ 2,
x is a value determined by the oxidation state of each element. ), Which is a known composition.

Specifically, for example, the following catalyst compositions (excluding oxygen atoms) can be mentioned. Mo ₁₂ Bi _0.1-5 Fe _0.5-5 Co _5-10 Cs _0.01-1 Si
_0.1-20 Mo ₁₂ W _0.1-2 Bi _0.1-5 Fe _0.5-5 Co _5-10 Cs
_0.01-1 Si _0.1-20 Mo ₁₂ W _0.1-2 Bi _0.1-5 Fe _0.5-5 Co _5-10 K _0.01-1
Si _0.1-20 Mo ₁₂ Bi _0.1-5 Fe _0.5-5 Co _5-10 Tl _0.01-1 P
_{0.01-2 Si 0.1-20 Mo 12 Bi 0.1-5 Fe} 0.5-5 Ni 5-10 Tl 0.01-1 P
_0.01-2 Si _0.1-20

The method for producing these composite oxide catalysts is generally disclosed in, for example, Japanese Patent Application Laid-Open No. 59-46132, in which ammonium molybdate and various metal salts are used as raw materials for catalyst components. Is prepared using.

As a raw material of the catalyst component, a combination of oxides, sulfates, nitrates, carbonates, hydroxides, ammonium salts, halides and the like of each element can be used. Specifically, for example, molybdenum trioxide, molybdic acid, ammonium paramolybdate or the like as a molybdenum raw material, bismuth oxide, bismuth nitrate, bismuth sulfate or the like as a bismuth raw material, iron (III) nitrate as an iron raw material,
Iron (III) sulfate, iron (III) chloride, etc. can be used.

The catalyst is usually produced by making these catalyst raw materials into an aqueous solution, mixing them, concentrating the mixed solution or the aqueous slurry containing the obtained catalyst component to dryness, and salt-decomposing the obtained dried product, Then, firing is performed. In the present invention, the mixing method such as the order of mixing the catalyst raw materials is not particularly limited.

In the present invention, the method for concentrating and drying the mixed solution or aqueous slurry containing the catalyst components does not need to be limited to a special method, and is well known in the art as long as the components are not unevenly distributed. Various methods such as evaporation to dryness by a kneader, box-type dryer, drum-type ventilation dryer, spray dryer and the like are used.

The dried product which is the obtained catalyst precursor contains ammonium salt such as ammonium nitrate, and by heating the dried product, elimination of the ammonium salt, so-called salt decomposition is carried out. At this time, the dried catalyst precursor was kept at a predetermined temperature in the range of about 200 to 450 ° C., preferably about 250 to 400 ° C. so that the ammonium salt could be rapidly desorbed from the surface of the catalyst. Add gradually to the circulating gas,
Perform salt decomposition. Although depending on the temperature conditions and the like, salt decomposition is completed in about several minutes, and at the latest about 10 minutes.

If a large amount of dried product is added at once, it is dangerous because salt decomposition occurs at once. As described above, the method of laminating or filling the dried product into the container and gradually heating it to a predetermined temperature is insufficient for desorption of the ammonium salt from the catalyst surface in the temperature rising process of the dried product, and the residual liquefied ammonium salt is left. It is considered that the catalyst component is eluted due to the above, but the chemical and physical properties of the catalyst are likely to vary, and the catalyst performance is not always sufficient, which is not preferable.

[0014] Thus in the present invention, by slowly adding a catalyst precursor dried product into a flowing gas maintained at a predetermined temperature, causing the elimination of the ammonium salt from the catalytic surface quickly performed It is a thing . The rate of addition of the flowing gas in the dry燥品is to gas flow surface 0. 1-10
It is kg / min · m ² . 0 . 1 kg / min · m ²
If it is slower, productivity will be poor, and it will also be 10 kg / min · m ²
If it is made earlier, the above problems occur, which is not preferable.

The apparatus used for salt decomposition may be any type of furnace capable of supplying a sufficient flow gas. Usually, a flash drying oven is used. Air is usually used as an atmospheric gas for salt decomposition, but an inert gas such as nitrogen, helium, or argon can also be used.

If the flow rate of the atmospheric gas at the time of salt decomposition is too small, the heat generated by the decomposition of the ammonium salt cannot be removed, and if it is too large, the fluidization of the dried product for salt decomposition becomes remarkable. Therefore the flow rate of the atmospheric gas in performing salt decomposition is a linear velocity 0.01~2m / sec at standard conditions.

The catalyst from which the ammonium salt has been eliminated by salt decomposition is then calcined. About 35 for firing in air
0-700 ° C, preferably about 400-600 ° C, about 1
Hold for ~ 40 hours.

The catalyst obtained is usually molded into a desired shape and used. It is molded into a ring shape, a pellet shape, or a spherical shape by tablet molding or extrusion molding. The catalyst is usually molded by salt decomposition and then calcined, but is not limited thereto.

The reaction conditions for the gas phase catalytic oxidation reaction of propylene or isobutylene with molecular oxygen can be carried out by a conventionally known method. For example, a reaction temperature of 280 to 400
Although the reaction temperature may be reduced at ℃, the reaction pressure is usually atmospheric pressure to 5
00 kPa, oxygen / olefin (molar ratio) is 1 to 3, and space velocity SV is 500 to 5000 / h.

[0020]

Industrial Applicability It is possible to obtain a composite oxide catalyst having a higher performance in the catalytic oxidation reaction of propylene and isobutylene than the catalyst obtained by the conventional method.

[0021]

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
The reaction rate (%), selectivity (%) and yield (%) are defined as follows. Reaction rate (%) = [(mol of supplied olefin)-(mol of unreacted olefin)] / (mol of supplied olefin) x 100 Selectivity (%) = (mol of product) / [( Number of moles of feed olefin)-(number of moles of unreacted olefin)] x 100 Yield (%) = (number of moles of product) / (number of moles of feed olefin) x 100

[0022] Example 1 Ammonium molybdate _{[(NH 4) 6 Mo 7} O 24 · 4H
₂ O] 211.9 g is dissolved in 400 g of warm water, and 2 more
30.6 g of 0% silica sol (SiO ₂ ) is added, and this is referred to as liquid A. Iron nitrate _{(III) [Fe (NO 3} ) 3 · 9H 2 O]
80.8g and cobalt nitrate _{[Co (NO 3) 2 ·} 6H
₂ O] 218.3 g and cesium nitrate (CsNO ₃ ) 1
1.7 g is dissolved in 300 g of warm water, and this is referred to as liquid B.
12g of 70% nitric acid was added to 60g of pure water to obtain bismuth nitrate.
Was dissolved _{[Bi (NO 3) 3 ·} 5H 2 O] 48.5g, which is referred to as liquid C. Next, solution B and solution C are mixed. The liquid mixture of B and C is added while stirring the liquid A, and then 66 g of 25% ammonia water is added to obtain a slurry. This was concentrated to dryness, and the obtained catalyst precursor, a dried product, was heated at a temperature of 360.
℃, linear velocity is 0.05m / sec (standard condition) under air flow gradually (about 1.3kg /
min ・ m ² ) Immediately decomposes salt. After that, it is crushed and tablet-molded into particles of 10 to 24 mesh, 530 ° C.
And calcined in air for 6 hours to obtain a catalyst. The catalyst composition excluding oxygen is Mo ₁₂ Bi ₁ Fe ₂ Co _7.5 Cs _0.6 Si ₁ . 7 g of the above catalyst was filled in a glass reaction tube having an inner diameter of 18 mm. The filling was performed by diluting with 14 mesh silicon carbide. The reaction was carried out under the reaction conditions of a feed gas having a molar ratio of isobutylene: oxygen: nitrogen: steam = 1: 2.2: 6.2: 2 and a space velocity SV = 750 / h. The results are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated, except that the catalyst precursor dried product was gently heated from room temperature to complete the salt decomposition at 250 ° C. The results are shown in Table 1.

[0024]

[Table 1]

Example 2 Example 1 was repeated except that the preparation scale was 30 times and the linear velocity of the air flow rate during pre-baking was changed to 0.5 m / sec.
Preparation and reaction were performed in the same manner as in. The results are shown in Table 2.

Comparative Example 2 The same procedure as in Example 2 was carried out except that the temperature of the dried catalyst precursor product was gradually raised from room temperature to terminate the calcination at 250 ° C. The results are shown in Table 2.

[0027]

[Table 2]

[0028] Example 3 Ammonium molybdate _{[(NH 4) 6 Mo 7} O 24 · 4H
₂ O] 114 g is dissolved in 470 g of warm water, and further 20%
0.4 g of silica sol (SiO ₂ ) ₂ is added, and this is referred to as liquid A. Iron nitrate _{(III) [Fe (NO 3} ) 3 · 9H 2 O ] 55
g and nickel nitrate _{[Ni (NO 3) 2 ·} 6H 2 O] 2
g and cobalt nitrate _{[Co (NO 3) 2 ·} 6H 2 O] 1
38.5 g and 3.3 g of thallium nitrate (TlNO ₃ ) are dissolved in 250 g of warm water, and this is designated as solution B. 40 g of pure water
9.4g of 60% nitric acid was added to bismuth nitrate [Bi (N
O ₃₎ was dissolved ₃ · 5H ₂ O] 33g, which is referred to as liquid C. Next, solution B and solution C are mixed. While stirring Solution A, B
Add a mixture of C and C, then add 25% aqueous ammonia 46
g to give a slurry. This was concentrated to dryness, and the obtained dried product had a temperature of 250 ° C. and a linear velocity of 0.25 m / sec.
It is gradually poured (about 1.3 kg / min · m ^{2 with} respect to the air flow surface) under the air flow (standard condition) to instantly decompose salt. Then, it was crushed, tablet-molded into particles of 10 to 24 mesh, and calcined in air at 500 ° C. for 6 hours to obtain a catalyst. The catalyst composition excluding oxygen is Mo ₁₂ Bi ₁ Fe ₂ Ni.
_{It is 0.1} Co ₇ Tl _0.18 Si ₁ . 12 g of the above catalyst was filled in a glass reaction tube having an inner diameter of 18 mm. Filling is 14
It was diluted with a silicon carbide of mesh. The feed gas is propylene: oxygen: nitrogen: steam = 1: 1.
The reaction was carried out at a molar ratio of 5: 6: 3 under the reaction conditions of space velocity SV = 818 / h. The results are shown in Table 3.

Comparative Example 3 The procedure of Example 3 was repeated, except that the catalyst precursor dried product was slowly heated from room temperature to complete the salt decomposition at 250 ° C. The results are shown in Table 3.

[0030]

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C07C 47/22 C07C 47/22 A 57/055 57/055 B // C07B 61/00 300 C07B 61/00 300 (56) Reference Documents JP-A-55-67340 (JP, A) JP-A-5-253480 (JP, A) JP-A-56-161841 (JP, A) JP-A-6-31171 (JP, A) JP-A-5- 329371 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B01J 21/00-38/74 C07C 27/14 C07C 45/35 C07C 47/22 C07C 57/055 C07B 61/00

Claims (3)

(57) [Claims] 1. The general formula Mo _a Bi _b Fe _c A _d B _e C _f D _g
O _x (wherein Mo, Bi and Fe are molybdenum,
Represents bismuth and iron, A represents nickel and / or cobalt, B represents at least one element selected from the group consisting of manganese, zinc, calcium, magnesium, tin and lead, C represents phosphorus, boron, Ar represents at least one element selected from the group consisting of tellurium, tungsten, antimony and silicon, D represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, and a = When 12 is set, 0 <b ≦ 10, 0 <c ≦ 10, 1 ≦ d ≦ 1
0, 0 ≦ e ≦ 10, 0 ≦ f ≦ 10, 0 <g ≦ 2,
x is a value determined by the oxidation state of each element. ) In the process for producing a catalyst for synthesizing a corresponding unsaturated aldehyde and unsaturated carboxylic acid by vapor-phase catalytic oxidation of propylene or isobutylene represented by the formula (3) , a mixed solution containing a catalyst component or solidified the aqueous slurry concentrated to dryness, the dried product containing an ammonium salt obtained was kept at a predetermined temperature in the range of 200 to 450 ° C. line
At a standard speed of 0.01 to 2 m / sec into the flowing gas , 0.1 to 10 kg / min · m with respect to the gas flowing surface
^A method for producing a catalyst, which comprises adding ammonium at a rate of ² to remove ammonium salt , and then calcining. 2. The method for producing a catalyst according to claim 1, wherein the circulating gas is air, nitrogen, helium or argon. 3. The method for producing a catalyst according to claim 1, which is calcined in air at 350 to 700 ° C. for 1 to 40 hours.