| 摘要 |
PROBLEM TO BE SOLVED: To provide a simple and inexpensive production process for α- hydroxycarboxylic acid of high purity. SOLUTION: An α-hydroxycarboxylic ester is subjected to reactive distillation in the presence of water. In other words, α-hydroxycarboxylic ester is hydrolyzed by the gas-liquid contact to prepare α-hydroxycarboxylic acid and simultaneously the alcohol formed as a by-product is distilled out of the reaction system. Glycolic esters are preferred as the α-hydroxycarboxylic ester, particularly methyl glycolate is preferred. The molar ratio of water to the α- hydroxycarboxylic ester (water/α-hydroxycarboxylic ester) is in the range of 1/1-20/1, more preferably 3/1-10/1. This reactive distillation can be carried out, when necessary, in the presence of an acid and/or an organic solvent that can form an azeotropic composition with water. |
