Purification process of polyhydroxycarboxylic acid

摘要

A purification process for polyhydroxycarboxylic acids which comprises dissolving polyhydroxycarboxylic acid in an water-immiscible phenol or an organic solvent containing said water-immiscible phenol, successively bringing the resulting solution into contact with water which contains an acidic material, separating the organic layer from an aqueous layer, and isolating polyhydroxycarboxylic acid from the organic layer. The process can efficiently remove a catalyst contained in the polyhydroxycarboxylic acid prepared in the presence of the catalyst, does not require polyhydroxycarboxylic acid to be in the form of a solid, and can treat polyhydroxycarboxylic acid in a higher concentration as compared with using chlorinated hydrocarbon as a solvent.