Process for preparing methacrylic acid

摘要

The present invention relates to a process for preparing methacrylic acid based on the hydrolysis of methacrylic esters.

主权项

1. A process for preparing methacrylic acid, the process comprising:
converting acetone cyanohydrin to methacrylamide; esterifying the methacrylamide in the presence of at least one alcohol, thereby obtaining at least one methacrylic ester; and hydrolyzing the at least one methacrylic ester in the presence of at least one heterogeneous catalyst, thereby obtaining methacrylic acid, wherein: a feed stream to the hydrolyzing comprises a water stream, and a methacrylic ester stream from the esterifying; a recirculation stream to the hydrolyzing comprises a first circulation stream from the input of a vacuum rectifying column for low boiler removal, and a second circulation stream from the output of a rectifying column for alcohol removal; and the mass ratio or the volume ratio of the recirculation stream to the feed stream ranges from 5-50.