Ube Industries, Inc.

Fumihiko Sakai

Sumio Umemura

Kyoji Ohdan

Yasuo Bando

Harumi Ikezawa

Toshihiko Hogami

Kenichi Suzuki

Masataka Fuginaga

Masataka Fuzinaga

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

Unsaturated hydrocarbons having 4 to 6 carbon atoms are catalytically oxidized into maleic anhydride by using a catalyst, which consists essentially of oxides of (A) vanadium, (B) phosphorus, (C) titanium and (D) optionally at least one element selected from sodium, calcium, magnesium, iron, zirconium, boron, manganese, silver and molybdenum in the atomic ratios defined by the following formula

Catalytic oxidative process for producing maleic anhydride

Maleic anhydride is prepared by the catalytic oxidation of unsaturated hydrocarbons having 4 to 6 carbon atoms, at a temperature of from 350.degree. to 500.degree. C., in the presence of a catalyst which is produced by a method wherein a mixture of a titanium oxide and a vanadium compound in an atomic ratio of from 1 to 15 is calcined at a temperature of from 630.degree. to 1000.degree. C. to prepare a precursory catalyst, and wherein a gas mixture containing an organic phosphorus compound and a carrier gas is brought into contact with a mass of the percursory catalyst at a supply rate of the phosphorus compound being from 0.01 to 10 millimoles/hr per 1 ml of the mass of the percursory catalyst and at a temperature of from 350.degree. to 600.degree. C. during when a total amount of from 0.3 to 30 millimoles of the phosphorus compound per 1 ml of the mass of the precursory catalyst passes through the mass of the precursory catalyst.

Process for the preparation of maleic anhydride catalyst

Unsaturated hydrocarbons having 4 to 6 carbon atoms are catalytically oxidized into maleic anhydride at relatively low temperatures in the range of 300.degree. C to 450.degree. C. The catalyst used consists essentially of oxides of vanadium, phosphorus, zirconium, and at least one element selected from manganese, boron, cadmium, silver, bismuth and zinc.

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Ube, Japan

Fumihiko Sakai