PREPARATION OF CATALYST FOR PREPARING METHACRYLIC ACID

PURPOSE:To obtain a catalyst capable of enhancing the yield of methacrylic acid as compared to a conventional catalyst, by a method wherein a solution having a compound containing a catalytic element mixed therein is concentrated and conditioned so as to adjust the moisture content thereof to a specific value and the resulting aolution is subjected to heat treatment at a specific temp. CONSTITUTION:A hetero polyacid type catalyst for preparing methacrylic acid, which contains p, Mo and V as catalytic elements and is used in preparing methacrylic acid by reacting methacrolein with molecurlar oxygen in the presence of a catalyst in a high temp. gas phase, is prepared. In this preparation method, a solution or a a slurry having a compound containing the catalytic element is concentrated or dried and, after the moisture content of the obtained concentrate or the dried substance is adjusted to 5-20wt%, heat treatment is carried out at 100-250 deg.C. In order to carry out side heat treatment effectively, it is pref. that abrupt heat treatment is carried out in a heating vessel preliminarily heated to 100-250 deg.C and the concentrate or the dried substance of which the moisture content is adjusted is dehydrated.