Mitsubishi Rayon Company, Limited

Masato Otani

Hideo Matsuzawa

Hiromichi Ishii

Motomu Oh-Kita

Masao Kobayashi

Toru Kuroda

Fumiki Murakami

Kantaro Yamada

Hiroshi Matsumura

Hasao Kobayashi

Hiroyuki Naito

Process for producing catalyst used for synthesis of methacrylic acid

A process for isolating methacrylic acid by solvent extraction from an aqueous methacrylic acid solution obtained from a gas phase catalytic oxidation reaction, characterized in that the aqueous methacrylic acid solution is previously first contacted with an extraction solvent, polymers precipitated out from the aqueous methacrylic acid solution are removed and the remainder is fed into an extraction column.

Process for isolating methacrylic acid by extraction

The gas phase catalytic oxidation of an unsaturated aldehyde with molecular oxygen at 240.degree. to 450.degree. C. to give the corresponding unsaturated carboxylic acid is conducted in the presence of a catalyst of the following formula:

Catalytic process for the preparation of unsaturated carboxylic acid

Acrylic acid or methacrylic acid is prepared by vapor-phase catalytic oxidation of acrolein or methacrolein, with molecular oxygen at a temperature of from 240.degree. to 450.degree. C in the presence of a catalyst represented by the formula:

Process and catalyst for preparing unsaturated carboxylic acid

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Otake, Japan

Masato Otani