Process for the preparation of alpha-hydroxy acids

摘要

A process for the preparation of an alpha -hydroxy acid from an aqueous solution of an ammonium salt of an alpha -hydroxy acid which process comprises: (a) a first step of concentrating the aqueous solution such that the concentration of the ammonium salt of the alpha -hydroxy acid is greater than 60 % by weight, without converting more than 20 % of the ammonium salt of the alpha -hydroxy acid, and (b) a second step of heating the solution obtained in step (a) in the presence of an entraining medium.