Patent ID: 8586499

Claim:
A method for producing a catalyst for the preparation of methacrylic acid comprising a heteropolyacid compound containing phosphorus, molybdenum and at least one element X selected from the group consisting of potassium, rubidium, cesium and thallium and having an atomic ratio of the element X to molybdenum (X:Mo) of 0.5:12 to 2:12, said method comprising the steps of: mixing aqueous slurry A containing starting compounds of said heteropolyacid compound in which an atomic ratio of the element X to molybdenum (X:Mo) is from 2:12 to 4:12, and aqueous slurry B containing starting compounds of said heteropolyacid compound in which an atomic ratio of the element X to molybdenum (X:Mo) is from 0:12 to 0.5:12 to form a slurry mixture, heat-treating the slurry mixture at a temperature of 100° C. or higher in a closed vessel, drying the slurry mixture, and calcining the dried mixture.