JPS6045858B2 - Method for producing methacrolein and methacrylic acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing methacrolein and methacrylic acid by contacting a mixture containing isobutylene and oxygen with a catalyst in the gas phase at high temperature.

That is, the method of the present invention has the general formula 2M0a, Sbb
, Bic, Fed, Nie, X, , Yg, is a method of catalytically oxidizing isobutylene in a gas phase using a catalyst represented by Ch.

However, in the formula, X is at least one element selected from potassium and cesium, and Y is at least one element selected from magnesium, zinc, cadmium, and tantalum.

In addition, a--i indicates the atomic ratio of each element, and a
When 12, ■0.2~2 generations c=0.2~12, d
■0.2~12, e=0.2~12, f ■0.01~
4, g=0.01 to 4, which is a value determined by the oxidation state of the catalyst. The catalyst of the present invention can be prepared by known methods.

The molybdenum source used in preparing the catalyst is preferably an oxide or a compound that becomes an oxide when ignited. Such compounds include ammonium molybdate and the like. In this catalyst, the effect of adding antimony component is extremely large, and by adding antimony,
Catalytic performance increases dramatically. As the antimony source, oxides, hydrous oxides, chlorides, etc. are preferable. Raw materials for other elements include metals, their oxides, chlorides, or acids;
Compounds that become oxides when ignited, such as ammonium salts and nitrates, are preferred.

A carrier can be used in preparing the catalyst. Silica, alumina, silicon carbide, etc. are used as the carrier. When carrying out the reaction of the present invention, it is preferable to use isobutylene as a raw material after diluting it with an inert gas.

Nitrogen, water vapor, carbon dioxide gas, etc. are used as the inert gas, and water vapor has a particularly favorable effect on improving the yield. Air or oxygen-enriched air is used as the oxygen source for oxidation.

The concentration of isobutylene in the raw gas mixture is 1-2% by weight
can be changed within the range. The concentration of oxygen can also vary from 1 to 20% by volume. The reaction pressure used is from normal pressure to several atmospheres. Reaction temperature is 200-450
℃, especially preferably 250 to 400℃, and the contact time is 0
．． A range of 5 to 10 seconds is preferred. The reaction can be carried out in a fluidized or fixed bed. EXAMPLES The present invention will be specifically explained below with reference to Examples. Parts in Examples indicate parts by weight. Moreover, the yield means the following. Example 1 29.3 parts of antimony trioxide was suspended in 200 parts of water,
To this was added 1766 parts of ammonium molybdate dissolved in 1000 parts of water, then 8.1 parts of cesium nitrate dissolved in 10 parts of water, and 1 part of bismuth nitrate dissolved in 1000 parts of water.
Add 0% nitric acid dissolved in the area marked with water, 101 parts of ferric nitrate, 145.4 parts of nickel nitrate dissolved in 5 (1) parts of water, and 21.4 parts of magnesium nitrate dissolved in the area marked with water. , the silica additive was added in the form of silica sol,
The obtained slurry was evaporated to dryness, dried at 120°C, molded, and calcined at 500°C for 6 hours under air circulation to form a catalyst (MOI).

, Sb2, Bil, Fe3, Ni6, CSO. ,,Mg
l). Using this catalyst, the temperature of the catalyst layer was set to 355°C.
A raw material mixture gas of 5% isobutylene, 12% oxygen, 48% nitrogen and 35% water vapor was added to this for a contact time of 3.
．． I passed it with alcohol. The product was analyzed by gas chromatography, and the total yield of methacrolein and methacrylic acid was 82.0%. Example 2 Example 1
In , zinc nitrate 24 without adding magnesium nitrate
．． Catalysts (MOl2, Sb2, Bil, Fe3, Ni6,
C.S.O. 5, Znl) was prepared.

Using this catalyst, the temperature of the catalyst layer was maintained at 350° C., and the reaction was carried out under the same conditions as in Example 1 except that a total yield of methacrolein and methacrylic acid of 82.0% was obtained. Example 3 A catalyst was prepared that differed from Example 1 only by not adding magnesium nitrate and adding 25.7 parts of cadmium nitrate to 50 parts of water.

Using this catalyst, a reaction was carried out under the same conditions as in Example 1, and a total yield of methacrolein and methacrylic acid of 82.0% was obtained. Example 4 A catalyst was prepared that differed from Example 1 except that 18.4 parts of tantalum oxide was added instead of adding magnesium nitrate.

Using this catalyst, a reaction was carried out under the same conditions as in Example 1 to obtain a total yield of methacrolein and methacrylic acid of 83.0%. Example 5 54.0 parts of antimony pentoxide was suspended in 200 parts of water,
To this, 176.6 parts of ammonium molybdate was added to 10 parts of water (1
) and then 4 parts of cesium nitrate, 2.5 parts of potassium nitrate dissolved in 1 part of water, 40.4 parts of bismuth nitrate dissolved in 5 parts of 10% nitric acid,
33.7 parts of ferric nitrate, 193 parts of nickel nitrate. water prostitute 5
(1) part dissolved in magnesium nitrate, and 10 parts magnesium nitrate
．． 7 parts of zinc nitrate and 12.4 parts of zinc nitrate dissolved in 4 parts of water were added, and finally a portion of silica was added in the form of silica sol.

The obtained slurry was evaporated to dryness, dried at 120° C., molded, and calcined at 500° C. for 6 hours under air circulation to prepare a catalyst. The catalyst composition is MOL. ,Sb4,Bll,F
el, Ni8, KO. ,,CSO. 3.MgO. 5,z
nO. , is. Using this catalyst, the temperature of the catalyst layer was increased to 3
The temperature was maintained at 60°C and the reaction was carried out under the same conditions as in Example 1, and the total amount of methacrolein and methacrylic acid was 83
．． Obtained 0%. Comparative Example 1 A catalyst was prepared that differed from Example 1 only in that no magnesium nitrate was added.

Using this catalyst, a reaction was carried out under the same conditions as in Example 1. As a result, the total yield of methacrolein and methacrylic acid was 78.00%. Comparative Example 2 A catalyst was prepared that differed from Example 1 only in that antimony trioxide was not added.

A reaction was carried out under the same conditions as in Example 1 using this catalyst. As a result, the total yield of methacrolein and methacrylic acid was 67.0%. Comparative Example 3 A catalyst was prepared in which the only difference from Example 1 was that antimony trioxide and magnesium nitrate were not added.

As a result of carrying out the reaction using this catalyst under the same conditions as in Example 1, the total yield of methacrolein and methacrylic acid was 6.
It was 3.0%. Comparative Example 4 A catalyst was prepared that differed from Example 1 only in that cesium nitrate was not added.

Claims (1)

[Claims] 1. A method for producing methacrolein and methacrylic acid, which comprises bringing a mixed gas containing isobutylene and oxygen into contact with a catalyst represented by the following general formula in a high-temperature gas phase. Mo_a, Sb_b, Bi_c, Fe_d, Ni_e,
X_f, Y_g, O_h However, in the formula, X is at least one alkali metal selected from potassium and cesium,
Y is at least one element selected from makenesium, zinc, cadmium, and tantalum. In addition, a~h indicates the atomic ratio of each element, and when a=12, b=0.2~
20, c==0.2-12, d=0.2-12, e=0
．． 2 to 12, f=0.01 to 4, and g=0.04 to 4, and h is a value determined depending on the oxidation state of the catalyst.