METHOD FOR PURIFYING METHACRYLIC ACID

摘要

Provided is a crystallization method by which a highly-pure methacrylic acid crystal can be produced with high productivity. The method for purifying methacrylic acid according to the present disclosure involves using crude methacrylic acid having a maleic acid concentration of 2000 ppm by mass or less and an acrylic acid concentration of 2000 ppm by mass or less and setting the slurry temperature to−10 to 10° C. in order to crystallize methacrylic acid. A suspension-type jacket-cooling-system crystallization vessel is used as the crystallization apparatus, and an absolute value of the difference between a crystallization temperature and a temperature of a cooling medium in the jacket is preferably 15° C. or less.