JPH0811187B2 - Preparation of catalysts for the production of methacrolein and methacrylic acid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for preparing a catalyst to be used for producing methacrolein and methacrylic acid by vapor phase catalytic oxidation of isobutylene or tert-butanol.

(Prior Art) A method of using a catalyst containing molybdenum-bismuth-iron-antimony in producing methacrolein and methacrylic acid by vapor-phase catalytic oxidation of isobutylene or tert-butanol, is disclosed in JP-B-47-32049. Has been proposed a lot.

JP-A-58-64134 is an invention that pays attention to the particle size of the raw material antimony trioxide when producing a molybdenum-bismuth-antimony-containing catalyst.

In this invention, it is reported that the use of antimony trioxide having an average particle size of 3 μm or less makes it possible to obtain a catalyst which is particularly effective in the production of acrylonitrile by ammoxidation of propylene.

[Problems to be solved by the invention]

All of the many known catalysts have various drawbacks such as insufficient reaction results, deterioration of catalytic activity over time, or too high reaction temperature. However, further improvement is desired.

[Means for solving problems]

The present invention is a multi-component containing at least molybdenum, bismuth, iron and antimony in a catalyst composition used for producing methacrolein and methacrylic acid by gas phase catalytic oxidation of isobutylene or tert-butanol with molecular oxygen. A method for preparing a catalyst for producing methacrolein and methacrylic acid, which comprises using, as a starting material, an antimony trioxide having an average particle size of 0.2 μm or less when preparing a system catalyst.

In the present invention, it is necessary to use antimony trioxide having an average particle size of 0.2 μ or less as a starting material.

It is known that ultrafine particle technology for particles has been developed at present and that new effects, which have not been heretofore known, may be exhibited when the particles are made into ultrafine particles. For example, in the article by Masahiro Uda, "Ultrafine Particle Technology Using Reactive Plasma Gas" (Volume 24, June issue, pp. 7 to 16), even if the same substance is made into ultrafine particles, magnetic properties, optical properties, It has been reported that properties that are not found in the lump state, such as electrical properties, chemical reactivity, and sinterability, appear.

In the case of antimony trioxide, it is known that the limit of fine particles up to about 1 μ is obtained by the usual dry ball milling method, and the limit of fine particles down to about 0.4 μ is obtained even by using the wet milling method.

Many of the commercially available antimony trioxides have an average particle size of about 0.5 to 7 μ, but ultrafine particles of antimony trioxide of 0.2 μ or less are used in the present invention, and are particularly preferable. The particle size is 0.1-0.01μ.

In order to obtain such ultrafine particles, a method by evaporation of antimony metal is preferable. It is of course possible to re-pulverize a commercially available product and classify the product having a particle size of 0.2 μ or less from this, but it is relatively inefficient because re-pulverization is difficult. The average particle size can be easily measured by an electron micrograph or BET adsorption method.

The composition of the catalyst obtained by the method of the present invention is not limited, but the preferred catalyst composition is within the range represented by the following general formula.

Mo _a Bi _b Fe _c Sb _d A _e B _f C _g D _h O _i where Mo, Bi, Fe, Sb and O represent molybdenum, bismuth, iron, antimony and oxygen, respectively, and A is tungsten, At least one element selected from the group consisting of tantalum and niobium is shown, B is at least one element selected from the group consisting of cobalt and nickel, and C is sulfur, tellurium, selenium, cerium,
Represents at least one element selected from the group consisting of germanium, magnesium, manganese, zinc, silica, chromium, silver, tin, barium and aluminum,
D represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium.

However, a, b, c, d, e, f, g, h and i represent the atomic ratio of each element, and when a = 12, b = 0.01 to 3 (preferably b = 0.1 to 2) c = 0.1 To 5 (preferably c = 0.5 to 4) d = 0.1 to 5 (preferably d = 0.3 to 3) e = 0 to 3 (preferably e = 0 to 2) f = 1 to 14 (preferably f = 3) To 10) g = 0 to 10 (preferably g = 0 to 8) h = 0.01 to 3 (preferably h = 0.1 to 2), and i is oxygen necessary to satisfy the valences of the above components. It is the number of atoms.

Examples of raw material compounds used for catalyst preparation include nitrates, ammonium salts, halides and oxides of each element.

In carrying out the present invention, first, the catalyst raw material excluding antimony trioxide is dissolved or dispersed in water. Although this raw material mixed solution may be heated to remove water and then antimony trioxide may be added, it is preferable to add antimony trioxide to the raw material mixed solution, stir well and then heat to remove water. When the solid thus obtained is heat-treated under air flow, the desired catalyst is obtained.

The catalyst obtained by the method of the present invention can be used by supporting it on an inert carrier such as silica, alumina, silica-alumina or silicone carbide, or by diluting it with these.

In carrying out the present invention, a molecular enzyme is added to isobutylene or tert-butanol as a raw material, and gas phase catalytic oxidation is carried out in the presence of the above catalyst. The molar ratio of isobutylene or tert-butanol to oxygen is 1: 0.5-
3 is preferable. The raw material gas is preferably diluted with an inert gas before use. The molecular oxygen used for the oxidation may be pure oxygen gas or air, but air is industrially advantageous. The reaction pressure is from normal pressure to several atmospheres. The reaction temperature is preferably in the range of 250 to 450 ° C., and the reaction can be carried out in a fluidized bed or a fixed bed.

〔Example〕

Parts in the following examples and comparative examples mean parts by weight, and analysis was performed by gas chromatography. Moreover, the reaction rate of isobutylene or tert-butanol, the selectivity of methacrolein and methacrylic acid to be formed, and the single-flow yield are defined as follows.

Of isobutylene or tertiary butanol Example 1 To 1000 parts of water, 500 parts of ammonium molybdate and 32.2 parts of cesium nitrate were added and stirred with heating (solution A).

Separately, add 250 parts of 60% nitric acid to 850 parts of water and homogenize it.
114.5 parts of bismuth nitrate was added and dissolved. To this, 286.0 parts of ferric nitrate and 480.7 parts of cobalt nitrate were sequentially added and dissolved (solution B).

Solution B is added to solution A to form a slurry, and the average particle size is 0.
51.6 parts of antimony trioxide (03μ) was added and the mixture was heated with stirring to evaporate most of the water.

After drying the obtained cake-like substance at 120 ° C, 500
It was baked at 10 ° C for 10 hours and molded.

The composition of the catalyst thus obtained is Mo ₁₂ Bi ₁ Fe ₃ Sb _1.5 Co ₇ Cs
Shown at _0.7 Ox.

The atomic ratio x of oxygen is a value naturally determined by the valences of other elements, and is omitted in the following display.

This catalyst was filled in a stainless steel reaction tube, and a raw material mixed gas of 5% isobutylene, 12% oxygen, 10% steam and 73% nitrogen was passed through the catalyst layer for a contact time of 2 seconds and reacted at 360 ° C.

As a result, the reaction rate of isobutylene was 93.0%, the selectivity of methacrolein and methacrylic acid was 88.0%, and the yield of methacrolein and methacrylic acid was 81.8%.

Comparative Example 1 A catalyst having the same composition was prepared in the same manner as in Example 1 except that antimony trioxide having an average particle size of 3 μ was used. Using this catalyst, a reaction was carried out under the same reaction conditions as in Example 1. As a result, the conversion of isobutylene was 90.0%, the selectivity of methacrolein and methacrylic acid was 87.7%, and the yield of methacrolein and methacrylic acid was 78.9%. Met.

Example 2 A catalyst having the following composition was prepared in the same manner as in Example 1, except that antimony trioxide having an average particle size of 0.05 μ was used. The composition of this catalyst was Mo ₁₂ Bi ₁ Fe _2.5 Sb _1.5 Ni ₈ Cr ₁ Rb _0.8 . Using this catalyst, a reaction was carried out under the same reaction conditions as in Example 1. As a result, the conversion of isobutylene was 93.1%, the selectivity of methacrolein and methacrylic acid was 91.6%, and the yield of methacrolein and methacrylic acid was 85.3%. Met.

Comparative Example 2 A catalyst having the same composition was prepared in the same manner as in Example 2, except that antimony trioxide having an average particle size of 5 μ was used. Using this catalyst, a reaction was conducted under the same reaction conditions as in Example 1. The reaction rate of isobutylene was 92.0%, the selectivity of methacrolein and methacrylic acid was 90.2%, and the yield of methacrolein and methacrylic acid was 83.0%. Met.

Example 3 A reaction was carried out under the same conditions as in Example 2 except that tert-butanol was used as a raw material using the catalyst of Example 2, and the reaction rate of tert-butanol was 100% and methacrolein and methacrylic acid were The selectivity was 86.2%, and the single-flow yields of methacrolein and methacrylic acid were 86.2%.

Comparative Example 3 A reaction was carried out under the same conditions as in Example 2 except that tert-butanol was used as a raw material using the catalyst of Comparative Example 2. The reaction rate of tert-butanol was 100%, and methacrolein and methacrylic acid were The selectivity was 83.3%, and the single-flow yields of methacrolein and methacrylic acid were 83.3%.

Example 4 Example 1 using antimony trioxide having an average particle size of 0.02μ
A catalyst was prepared in the same manner as in. The composition of this catalyst is Mo ₁₂ Bi.
_{It was 1} Fe ₃ Sb _1.5 Ni ₇ Co ₁ Ag _0.1 Cs _0.7 . Using this catalyst, a reaction was carried out at a reaction temperature of 355 ° C. under the same reaction conditions as in Example 1. As a result, the conversion of isobutylene was 94.2%, the selectivity of methacrolein and methacrylic acid was 91.1%, and the methacrolein and methacrylic acid were simple. The flow yield was 85.8%.

Comparative Example 4 A catalyst having the same composition was prepared in the same manner as in Example 4, except that antimony trioxide having an average particle size of 3 μ was used. Using this catalyst, at a reaction temperature of 355 ° C. and under the same reaction conditions as in Example 1, a reaction rate of isobutylene of 92.1%,
The selectivity of methacrolein and methacrylic acid was 89.7%, and the single-flow yield of methacrolein and methacrylic acid was 82.6%.

Example 5 Example 1 using antimony trioxide having an average particle size of 0.1 μ
A catalyst was prepared in the same manner as in. The composition of this catalyst is Mo ₁₂ Bi.
_{It was 1} Fe ₃ Sb ₁ Ni ₇ Sn ₁ S _0.3 Tl _0.2 . Using this catalyst, a reaction was carried out at a reaction temperature of 355 ° C. under the same reaction conditions as in Example 1. As a result, the conversion of isobutylene was 91.0%, the selectivity of methacrolein and methacrylic acid was 92.0%, and the methacrolein and methacrylic acid were simple. The flow yield was 83.7%.

Comparative Example 5 A catalyst having the same composition was prepared in the same manner as in Example 5, except that antimony trioxide having an average particle size of 2 μ was used. Using this catalyst, at a reaction temperature of 355 ° C. and under the same reaction conditions as in Example 1, a reaction rate of isobutylene of 90.0%,
The selectivity of methacrolein and methacrylic acid was 91.4%, and the single-flow yield of methacrolein and methacrylic acid was 82.3%.

Example 6 Example 1 was performed using antimony trioxide having an average particle size of 0.02μ.
A catalyst was prepared in the same manner as in. The composition of this catalyst is Mo ₁₂ Bi.
_{It was 0.5} Fe _2.5 Sb ₁ Ni ₇ Te _0.5 Si ₁ K _0.2 Cs _0.4 . Using this catalyst, at a reaction temperature of 355 ° C. and under the same reaction conditions as in Example 1, a reaction rate of isobutylene of 93.3%, a selectivity of methacrolein and methacrylic acid of 91.6%, and a simple reaction of methacrolein and methacrylic acid were obtained. The flow yield was 85.5%.

Comparative Example 6 A catalyst having the same composition as in Example 6 was prepared except that antimony trioxide having an average particle size of 0.7 μm was used. When a reaction was carried out using this catalyst at a reaction temperature of 355 ° C. under the same reaction conditions as in Example 1, the reaction rate of isobutylene was 91.2
%, Methacrolein and methacrylic acid selectivity 91.3%,
The single-flow yield of methacrolein and methacrylic acid was 83.3%.

Example 7 Example 1 was performed using antimony trioxide having an average particle size of 0.03μ.
A catalyst was prepared in the same manner as in. The composition of this catalyst is Mo ₁₂ Bi.
_{It was 1} Fe ₂ Sb ₁ W _0.3 Co ₇ Mg ₂ Tl _0.2 . Using this catalyst, a reaction was carried out at a reaction temperature of 350 ° C. under the same reaction conditions as in Example 1. As a result, the conversion of isobutylene was 95.0%, the selectivity of methacrolein and methacrylic acid was 92.6%, and the methacrolein and methacrylic acid were simple. The flow yield was 88.0%.

Comparative Example 7 A catalyst having the same composition as in Example 7 was prepared except that antimony trioxide having an average particle size of 0.9 μ was used. Using this catalyst and conducting a reaction at a reaction temperature of 350 ° C. under the same reaction conditions as in Example 1, the reaction rate of isobutylene was 93.0.
%, Selectivity of methacrolein and methacrylic acid 92.3%,
The single-flow yield of methacrolein and methacrylic acid was 85.8%.

Example 8 A reaction was carried out under the same conditions as in Example 7 except that tert-butanol was used as a raw material using the catalyst of Example 7, and the reaction rate of tert-butanol was 100% and methacrolein and methacrylic acid were The selectivity was 89.3%, and the single-flow yields of methacrolein and methacrylic acid were 89.3%.

Comparative Example 8 The reaction was carried out under the same conditions as in Example 7 except that tert-butanol was used as the raw material using the catalyst of Comparative Example 7, and the reaction rate of tert-butanol was 100% and methacrolein and methacrylic acid were The selectivity was 86.5%, and the single-flow yields of methacrolein and methacrylic acid were 86.5%.

Example 9 Example 1 was performed using antimony trioxide having an average particle size of 0.03μ.
A catalyst was prepared in the same manner as in. The composition of this catalyst is Mo ₁₂ Bi.
_{It was 0.7} Fe _2.5 Sb _1.2 Ta _0.2 Ni ₇ Se ₁ Al ₁ Cs _0.7 . Using this catalyst and conducting a reaction at a reaction temperature of 350 ° C. under the same reaction conditions as in Example 1, the conversion of isobutylene was 94.1%, the selectivity of methacrolein and methacrylic acid was 93.1%, and the methacrolein and methacrylic acid were the only monomers. The flow yield was 87.6%.

Comparative Example 9 A catalyst having the same composition as in Example 9 was prepared except that antimony trioxide having an average particle size of 4 μm was used. Using this catalyst and conducting a reaction at a reaction temperature of 350 ° C. under the same reaction conditions as in Example 1, the reaction rate of isobutylene was 92.1%,
The selectivity of methacrolein and methacrylic acid was 92.4%, and the single-flow yield of methacrolein and methacrylic acid was 85.1%.

Example 10 Example 1 using antimony trioxide having an average particle size of 0.05μ
A catalyst was prepared in the same manner as in. The composition of this catalyst is Mo ₁₂ Bi.
_{It was 0.9} Fe ₂ Sb _1.5 W _0.3 Nb _0.1 Co ₈ Ce _0.5 Ba ₁ Cs _0.5 . Using this catalyst and conducting a reaction at a reaction temperature of 350 ° C. under the same reaction conditions as in Example 1, the reaction rate of isobutylene was 95.3.
%, Selectivity of methacrolein and methacrylic acid 94.0%,
The single-flow yield of methacrolein and methacrylic acid was 89.6%.

Comparative Example 10 A catalyst having the same composition was prepared in the same manner as in Example 10, except that antimony trioxide having an average particle size of 3 μ was used. Using this catalyst, a reaction was carried out at a reaction temperature of 350 ° C. under the same reaction conditions as in Example 1. The reaction rate of isobutylene was 93.1%,
The selectivity of methacrolein and methacrylic acid was 93.0% and the single-flow yield of methacrolein and methacrylic acid was 86.6%.

Example 11 Example 1 using antimony trioxide having an average particle size of 0.08μ
A catalyst was prepared in the same manner as in. The composition of this catalyst is Mo ₁₂ Bi.
_{It was 0.6} Fe ₃ Sb ₁ Ta _0.5 Co ₈ Zn ₁ Mn _0.1 Ge _0.3 Rb _0.8 . When a reaction was carried out using this catalyst at a reaction temperature of 350 ° C. under the same reaction conditions as in Example 1, the reaction rate of isobutylene was 95.0.
%, Methacrolein and methacrylic acid selectivity 93.2%,
The single-flow yield of methacrolein and methacrylic acid was 88.5%.

Comparative Example 11 A catalyst having the same composition as in Example 11 was prepared except that antimony trioxide having an average particle size of 1 μm was used. Using this catalyst, at a reaction temperature of 350 ° C. and under the same reaction conditions as in Example 1, a reaction rate of isobutylene was 93.0%,
The selectivity of methacrolein and methacrylic acid was 92.4%, and the single-flow yield of methacrolein and methacrylic acid was 85.9%.

Example 12 When the reaction was performed under the same conditions as in Example 11 except that tert-butanol was used as a raw material using the catalyst of Example 11, the reaction rate of tert-butanol was 100%, and methacrolein and methacrylic acid The selectivity was 89.0%, and the single-flow yields of methacrolein and methacrylic acid were 89.0%.

Comparative Example 12 When the reaction was carried out under the same conditions as in Example 11 except that tert-butanol was used as the raw material using the catalyst of Comparative Example 11, the reaction rate of tert-butanol was 100%, and methacrolein and methacrylic acid The selectivity was 86.8%, and the single-flow yields of methacrolein and methacrylic acid were 86.8%.

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Claims (1)

[Claims] 1. A catalyst composition containing at least molybdenum, bismuth, iron and antimony in a catalyst composition used for producing methacrolein and methacrylic acid by vapor-phase catalytic oxidation of isobutylene or tert-butanol with molecular oxygen. A method for preparing a catalyst for producing methacrolein and methacrylic acid, which comprises using, as a starting material, an antimony trioxide having an average particle size of 0.2 μ or less in preparing a component catalyst.