METHOD FOR COLLECTING METHACRYLIC ACID

PROBLEM TO BE SOLVED: To utilize the bottoms in a methacrylic acid purification column. SOLUTION: This method for producing methacrylic acid comprises the following process: a mixed gas obtained by catalytic vapor phase oxidation reaction of at least one compound selected from the group consisting of isobutylene, t-butyl alcohol, methacrolein and mixtures thereof with a molecular oxygen-containing gas is brought into a methacrylic acid collection column and collected as a methacrylic acid-containing liquid, which is then put to distillation (and extraction) to obtain crude methacrylic acid, which, in turn, is subjected to distillation to obtain the objective purified methacrylic acid. The method is characterized by involving feeding the bottoms from the purification column used for the distillation of the crude methacrylic acid into at least one step selected from the methacrylic acid collection step, the distillation step for the methacrylic acid-containing liquid, the extraction step for the methacrylic acid-containing liquid and the esterification step comprising reaction between the crude methacrylic acid and an alcohol.