METHOD OF PRODUCING ALPHA-HYDROXY CARBOXYLIC ACIDS Russian patent published in 2012 - IPC C07C67/20 C07C67/54 C07C69/675 

FIELD: chemistry.

SUBSTANCE: invention relates to an improved continuous method of producing esters of alpha-hydroxy carboxylic acids, in which an amide of alpha-hydroxy carboxylic acid reacts with alcohol as the starting components in the presence of a catalyst to obtain a mixture of products containing esters of alpha-hydroxy carboxylic acids, ammonia, unreacted amide of alpha-hydroxy carboxylic acid, as well as alcohol and a catalyst, in which a) streams of starting components containing amide of alpha-hydroxy carboxylic acid, alcohol and catalyst as the starting components are fed into a high-pressure reactor; b) the streams of starting components react with each other in the high-pressure reactor at pressure from 1 bar to 100 bar; c) the mixture of products obtained at step b), which contains esters of alpha-hydroxy carboxylic acids, unreacted amide of alpha-hydroxy carboxylic acid and catalyst, is removed from the high-pressure reactor; and d) alcohol and ammonia content in the mixture of products is reduced, where ammonia is removed by distillation under pressure which is constantly kept higher than 1 bar without recourse to additional cleaning agents. The continuous method is especially expedient when used on an industrial scale.

EFFECT: improved continuous method of producing esters of alpha-hydroxy carboxylic acids.

30 cl, 12 ex, 2 tbl, 2 dwg