PROCESS FOR THE PURIFICATION OF A SOLUTION CONTAINING METHACRYLIC ACID AND TRACE IMPURITIES

摘要

A process of obtaining pure methacrylic acid involves the catalytic oxidation of a compound having 4 carbon atoms with a gas containing molecular oxygen and steam to produce methacrylic acid which is then brought into contact with a basic anion-exchange resin so as to remove byproduced dibasic acids and the like from the methacrylic acid. Strongly or weakly basic anion-exchange resins can be used; maleic acid and citraconic acid in the methacrylic acid can be reduced to the limit of detection (about 1 ppm). The methacrylic acid can be subjected to solvent extraction and/or distillation before it is brought into contact with the resin. By using maleic acid as an eluent, citraconic acid adsorbed on the resin during purification can be recovered.