Oxide catalysts and process for preparation thereof

Claim 2

In a process for preparing an oxide catalyst composed of vanadium oxide and titanium oxide in which more than 50% of the titanium oxide is in the rutile crystalline form, the improvement comprising calcining an intimate mixture of (a) vanadium oxide or a vanadium compound which, when calcined in an oxidizing atmosphere at 400° to 600°C. will give vanadium oxide and (b) a titanium oxide hydrogel which when dried at 250°C. will give titanium oxide having a crystallite size of not more than 70 A as calculated by the Sherrer method based on its X-ray diffraction peak at 2θ=25.4°, in an oxidizing atmosphere containing more than 10% by volume of oxygen at a temperature of 400° to 600°C.

Claim 3

In a process for preparing an oxide catalyst composed of vanadium oxide, titanium oxide and silica in which more than 50% of the titanium oxide is in the rutile crystalline form, the improvement comprising calcining an intimate mixture of (a) vanadium oxide or a vanadium compound which, when calcined in an oxidizing atmosphere at 400° to 600°C will give vanadium oxide, (b) a titanium oxide hydrogel which when dried at 250°C. will give titanium oxide having a crystallite size of not more than 70 A as calculated by the Sherrer method based on its X-ray diffraction peak at 2θ=25.4°, and (c) silica, in an oxidizing atmosphere containing more than 10% by volume of oxygen at a temperature of 400° to 600°C.

Claim 4

In a process for preparing an oxide catalyst composed of vanadium oxide, titanium oxide and silica in which more than 50% of the titanium oxide is in the rutile crystalline form, the improvement comprising calcining an intimate mixture of (a) vanadium oxide or a vanadium compound which, when calcined in an oxidizing atmosphere at 400° to 600°C will give vanadium oxide, (b) a titanium oxide hydrogel which when dried at 250°C. will give titanium oxide having a crystallite size of not more than 70 A as calculated by the Sherrer method based on its X-ray diffraction peak at 2θ=25.4°, and (c) silica, in an oxidizing atmosphere containing more than 10% by volume of oxygen at a temperature of 400° to 600°C.

Claim 5

The process of claim 1 in which the intimate mixture is prepared by drying a mixture consisting of an aqueous solution of the vanadium oxide or vanadium compound and the hydrogel of titanium oxide.

Claim 6

The process of claim 2 wherein said intimate mixture is prepared by drying a mixture consisting of an aqueous solution of the vanadium oxide or vanadium compound, the hydrogel of titanium oxide and a aqueous colloidal solution of silica.

Claim 7

The process of claim 4 wherein said intimate mixture consists of components in such a proportion that the final catalyst composition to be obtained by calcination has a titanium-to-vanadium atomic ratio of 0.1 to 10 and a silica content of 10 to 90% by weight.

Claim 8

The process of claim 4 wherein said drying is spray drying.

Claim 9

An oxide catalyst suitable for use as a fluidized bed catalyst for preparing acetic acid by the gaseous phase oxidation of butenes, said catalyst consisting essentially of vanadium oxide, titanium oxide and silica, and having the following features: a titanium-to-vanadium atomic ratio 0.1 to 10 a rutile content of titanium oxide more than 50% a silica content based on the total weight of the composition 10-90% by weight a bulk density 0.6 - 1.2 g/ml. a specific surface area 10 - 200 m.sup.2 /g a pore volume 0.1 - 0.5 ml/g a pore diameter at least 50 A.

Claim 10

An oxide catalyst suitable for use as a fluidized bed catalyst for preparing acetic acid by the gaseous phase oxidation of butenes, said catalyst consisting essentially of vanadium oxide, titanium oxide and silica, and having the following features: a titanium-to-vanadium atomic ratio 0.1 to 10 a rutile content of titanium oxide more than 50% a silica content based on the total weight of the composition 10-90% by weight a bulk density 0.6 - 1.2 g/ml. a specific surface area 10 - 200 m.sup.2 /g a pore volume 0.1 - 0.5 ml/g a pore diameter at least 50 A.

Claim 11

The process of claim 1 wherein said oxidizing atmosphere is air in which the calcination is conducted.

Claim 12

The process of claim 1 wherein said intimate mixture consists of components (a) and (b) in such a proportion that the final catalyst composition to be obtained by calcination has a titanium-to-vanadium atomic ratio of from 0.1 to 10.