Process for producing sorbic acid

摘要

A process produces sorbic acid by hydrolyzing a polyester with an aqueous hydrochloric acid solution having a concentration of 15% by weight or less under the application of pressure or at a temperature of 100°C or higher, which polyester is obtained by reaction between crotonaldehyde and ketene. In this process, the polyester may be hydrolyzed with a 3 to 10% by weight aqueous hydrochloric acid solution at a temperature of from 115°C to 140°C. A reaction mixture after hydrolysis of the polyester may be subjected to solid-liquid separation and the resulting filtrate may be recycled and reused in the hydrolysis reaction of the polyester. This process can significantly reduce the amount of tar formed during decomposition of the polyester, can produce sorbic acid in a high yield, and can reduce the load on the treatment of waste filtrates formed during purification operation.