| abstract |
(57) Abstract: A method for producing a heteropolyacid catalyst having a higher reaction activity and selectivity and a longer catalyst life, which is used for the production of methacrylic acid by vapor phase oxidation of methacrolein, and methacrylic acid by the catalyst. Of manufacturing method of. SOLUTION: In producing an oxidation catalyst containing phosphorus, molybdenum and an alkali metal or thallium, a solution prepared by dissolving or suspending a catalyst raw material in water is dried to obtain 150-35. After precalcining at 0 ° C., the solid obtained is kneaded with aqueous ammonia to adjust the solid to neutral or alkaline, then dried and calcined, and the presence of the resulting oxidation catalyst. Below, methacrolein is vapor-phase oxidized. |