Ube Industries, Inc.

Kenichi Suzuki

Sumio Umemura

Kyoji Ohdan

Fumihiko Sakai

Toshihiko Hogami

Yasuo Bando

Terumi Hisayuki

Masataka Fuginaga

Fumio Adachi

An improved catalyst suitable for use in the production of an unsaturated carboxylic acid by the catalytic vapor phase oxidation of an unsaturated aldehyde is provided. In this catalyst, a heat-resistant inorganic substance, such as alumina, silica-alumina and silicon carbide, having a particle diameter of 3 through 10 mm, an apparent porosity of 35 through 60%, a water absorption of 20 through 50%, an average pore diameter of not less than 40 microns, a specific surface area of not more than 2 m.sup.2 /g and a bulk specific gravity of 1.5 through 2.0 is used for supporting a composition containing molybdenum, phosphorus, vanadium and the alkali metals. The use of the above-mentioned carrier results in the advantages that the unsaturated carboxylic acid, such as methacrylic acid, can be selectively produced from the unsaturated aldehyde at a high yield and that the mechanical strength of the catalyst is remarkably improved.

Catalyst for production of unsaturated carboxylic acid, preparation

Methacrolein is catalytically oxidized into methacrylic acid in the vapor phase at a temperature of 200.degree. to 450.degree. C. The catalyst used is comprised of molybdenum, phosphorus, potassium and/or cesium, vanadium, silver and/or tellurium, and oxygen, and represented by the formula:

Catalytic oxidation of methacrolein

Methacrolein is produced in a high yield by catalytically oxidizing isobutylene at a temperature of from 250.degree. to 500.degree. C. by using a catalyst represented by the formula:

Process for producing methacrolein

Isobutylene is catalytically oxidized in the vapor phase with molecular oxygen to form methacrolein. The catalyst used consists essentially of metal oxides and is represented by the formula:

Catalytic oxidation of isobutylene

Methacrylic acid can be produced from methacrolein with a high reaction percentage of methacrolein and a high selectivity percentage of methacrylic acid, by bringing a reaction feed containing methacrolein and molecular oxygen into contact with an oxidation catalyst at a temperature of 200 to 450.degree. C, the oxidation catalyst comprising oxides of molybdenum, phosphorus, calcium, at least one element selected from the group consisting of arsenic, bismuth, tin, titanium, tantalum and boron and, optionally, at least one element selected from the group consisting of antimony, niobium and magnesium.

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Ube, Japan

Kenichi Suzuki