KR810000516B1 - Method for producing unsaturated acid - Google Patents

Abstract

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Description

Method for producing unsaturated acid

The present invention relates to a catalyst for use in the process for producing unsaturated acid from unsaturated aldehydes with low calorific value, excellent yield and few by-products, and also relates to its use. At this time, the catalyst is composed of an active ingredient consisting of molybdenum, phosphorus, arsenic, copper, oxygen and the like and other inert supports.

A catalyst consisting of molybdenum, phosphorus, arsenic, copper and ammonium is recorded in West German Patent No. 2353131. A catalyst coated on a support having a macropore on the outside using an oxide such as molybdenum, arsenic, phosphorus, and cobalt, aluminum, copper, and the like as necessary is introduced in US Patent No. 3761516. However, these catalysts have much lower yields when producing acrylic acid or methacrylic acid than the catalyst of the present invention.

In the case of producing acrylic acid or methacrylic acid from acrolein or methacrolein, it was found that the yield was significantly improved when the catalyst having the following composition was strongly coated on the surface of the inert support and operated at 200 ° to 500 ° C.

Mo ₁₂ P _b AscCud Of

B, c, d in the unit is 0.001 to 10 and f is the number of oxygen required to balance the other elements.

When the above-described coated catalyst is used for the production of unsaturated acid, the calorific value is low and the control of the reaction is easy. It also has good yields and fewer byproducts.

Main point of the present invention relates to the use of a coated catalyst. In this case, the coating catalyst refers to a catalyst in which the inner layer is composed of an inert support and the active layer is coated on the outer layer. Such a catalyst can be prepared by various methods.

The particle size of the above-mentioned inert support is 20 µm or more in diameter, and suitable particles for industrial reactors are preferably spherical particles having a diameter of 0.2 to 2 cm.

At least a part of the material used as the support in the present invention should be porous. The reason for the above is that the support must be water-soluble to wet the liquid. More suitable as a support, among others, can absorb moisture corresponding to 1% or more of the support mass. Examples of the material of the inert support include aluminum, silica, alumina, alumina-silica, silicon carbide, titania, zirconia, and the like, among which aluminum, silica, alumina, alumina-silica, and the like are preferable.

The amount of the active ingredient in the catalyst of the present invention may be any amount, but it may be present in an amount of about 10 to 100% based on the mass of the support.

In the production of the coated catalyst of the present invention, even if a part of the inert support is wetted with a liquid such as water, the liquid is not visible on the surface. The support made in this way is brought into contact with the active ingredient by rolling and such an operation can be easily carried out in a closed container. At this time, it is better not to add another 2 batches until 1 batch is completely coated.

The catalyst of the present invention can be made by the following special method:

(1) preferentially absorb and wet an inert support with a diameter of 20 µ or more with a slight excess of liquid, and (2) dry it again so that only a part of it is wetted so that no liquid appears on the surface, but part of the liquid is absorbed by the support. (3) the partially wetted support is contacted with a powder composed mainly of active ingredients, and (4) the partially active support and the catalytically active oxide are slowly stirred to form a catalyst having an active layer formed on the outer layer of the support.

In addition to the methods described above, (1) a certain amount of liquid is treated to a support having a diameter of 20 mu or more to form a partially wetted support (where the liquid is not visible on the surface of the support) and (2) a partially wetted catalytically active oxide. There is a method of making a catalyst in which the active layer is formed on the outer layer of the support by contacting the support and (3) slowly stirring the active oxide and the support.

The catalysts which have finished the above treatment can continue the drying treatment activation treatment or the like depending on the type of catalyst required.

The preparation of the catalyst of the present invention can be made by combining the catalytically active component using a support effective for producing methacrylic acid in methacrolein.

The catalyst of the present invention is a catalyst in which an active ingredient is strongly adhered and coated on the surface of an inert support. The catalytically active component must be present on the surface of the support and must not penetrate into the inert support. In this regard, the catalyst of the present invention is completely different from the conventional method of producing a catalyst in which the inert support is treated with an active ingredient in a liquid or slurry state to make the active ingredient penetrate into the support.

Plasticization of the catalyst is achieved by heating the dry catalyst component at 200 ° to 700 ° C. As plasticization temperature at this time, 325 degreeC-425 degreeC is more preferable.

Among the catalysts of the above-mentioned composition, a catalyst having b of 0.01 to 5, C of 0.01 to 5 and d of 0.001 to 5 is more preferable, particularly a catalyst of b of 0.5 to 1.5, C of 0.1 to 1 and d of 0.1 to 1 Most preferred.

The reaction of oxidizing acrolein to acrylic acid or methacrolein to methacrylic acid is well known. Generally, the reaction proceeds at 200 ° to 500 ° C., but in the case of the present invention, 250 ° to 370 ° C. is preferable. At this time, the reaction pressure is possible above atmospheric pressure, and below, and the contact time is within 1 to 2 seconds. The reactor in this reaction is most preferably a fixed bed type but may form a fluidized bed if the particles are small enough.

Enumerating the basic advantages of the present invention

(1) When the catalyst of the present invention is used, the calorific value is low.

In other words, the temperature difference between the reactor and the reaction temperature is smaller than that of the catalyst used alone or mixed with a support.

(2) The use of the coated catalyst of the present invention provides better conversion than other uncoated catalysts.

(3) By using the coating catalyst of the present invention, it is possible to prevent formation of unnecessary acetic acid and the like.

The method for producing unsaturated acid using the catalyst of the present invention as described above has considerable commercial value.

In the following, some specific examples will be listed and comparative examples A to D and Examples 1 to 11 prepare methacrylic acid using the coated catalyst of the invention and also conventional uncoated catalysts.

The active _ingredients of the catalysts of Comparative Examples A to D and Example 1 are Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of and the catalyst is made as follows. (NH ₄ ) ₆ M ₇ O ₂₄ 105.9 g of 4H ₂ O and 600 ml of distilled water are stirred and heated. 3.97 g of NH ₄ H ₂ AsO ₄ is added thereto, and when heated for 20 minutes, the color becomes white. When 2.5 g of copper acetate is added again, the color becomes blue, and 85% phosphoric acid is added thereto. After 10 minutes, hydrazine hydrate is added to the blue solution to evaporate to make porridge and dried.

Comparative Example A:

Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of

The catalyst component as described above is ground and selected from 14 to 30 mesh.

Comparative Example B

25% Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of + 75% Al ₂ O ₃

Infiltrate active ingredients into a small surface area Norton SA-5209 1/8 inch Alun Doomgu.

Comparative Example C:

25% Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of + 75% Al ₂ O ₃

Q-Loid A-30, which is a colloidal alumina, is mixed with a catalytically active component solution and dried, followed by trituration with 14 to 30 mesh.

Comparative Example D

25% Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of + 75% Al ₂ O ₃

NortonBA-106, fine powder alumina, is mixed with catalytically active solution and dried.

Example 1

25% Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of + 75% Al ₂ O ₃

인치 알룬둠구 50g에 1.8cc의 물과 16.7g의 촉매활성분을 5회에 걸쳐 가한다. 가하는 도중 또는 후에 알룬둠을 초자기내에서 굴린다. 그 결과 알룬둠지지체에 강력히 점착코팅된 일정한 크기와 균일한 코팅의 촉매가 생겼다.10 to 30 mesh Norton SA 5223

To 50 g of inch Alunduum ball, 1.8 cc of water and 16.7 g of catalytically active component are added five times. Roll Alunduum in grass during or after application. As a result, a catalyst of constant size and uniform coating strongly adhered to the Alundum support was produced.

Example 2

25% Mo ₁₂ P _1.0 As _0.5 Gu _0.25 Of + 75% Alundulum

Treatment is carried out by the method of Example 1 except that 5.8 g of phosphoric acid is used.

Comparative Examples E through T and Examples 3 through 6

Effect of coating catalyst using Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of as catalyst active ingredient when preparing methacrylic acid: 40ml at 370 ℃ Plasticize with air / min. The catalyst particles are filled in a 20 cm diameter stainless steel tube provided with a 0.3 cm diameter axial heater. In Examples K to N, thermocouples are installed. The reactor is heated through air and passed over the catalyst with a contact time of 2-3 seconds with the ratio of methacrolein / air / nitrogen / vapor being 1 / 5.7 / 4.6 / 8.6. The reaction remains in this state and the result is assessed by collecting and analyzing the product. These reaction conditions and results are reported in Table 1. The definition of term at this time is as follows.

TABLE 1

Effect of Methacrylic Acid Preparation on the Catalyst as Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of

[Examples 7 to 11]

25% Mo ₁₂ P _1.32 As _0.5 Gu _0.25 Of + 75% Alundum was made in the method of Example 2 and used for the conversion of methacrolein.

The reaction conditions and results are reported in Table 2.

TABLE 2

Methacrylic Acid Production Effect of Coated Catalyst (25% Mo ₁₂ P _1.0 As _0.5 Gu _0.25 Of + 75% Alundum)

The catalyst is not fully activated.

Claims (1)

In the method for producing acrylic acid or methacrylic acid by oxidizing acrolein or methacrolein, the active ingredient represented by the general formula (I) below at 200 DEG to 500 DEG C is selected from silica, alundum, alumina, alumina silica, and carbonization. A method for producing an unsaturated acid, characterized in that an oxide or oxide composite coated active catalyst is prepared by strongly adhering to the surface of an inert support having a diameter of 20 µ or more selected from the group consisting of silicon, titanium and zirconia to form a continuous coating layer. Mo ₁₂ P _b AscCudOf (I) In the above general formula, b, c, d represents the number of 0.001 to 10, f represents the number of oxygen required according to the valence state of other elements.