METHOD FOR PRODUCING HIGH PURITY GLYCOLIC ACID CRYSTALS

摘要

A process for producing highly pure glycolic acid crystals comprises: (1) forming a glycolic acid aqueous solution (A) that satisfies specific conditions, (2) precipitating the crystals of glycolic acid from solution, and (3) separating the crystals from the solution (A). A process for producing highly pure glycolic acid crystals comprises: (1) forming a glycolic acid aqueous solution (A) that satisfying: (a) the water content is 5-20 wt.%, (b) the mass ratio of the glycolic acid in terms of the monomer, i.e. ((the mass of monomeric glycolic acid contained in (A) + the mass of glycolic acid monomer constituting the glycolic acid condensates contained in (A))/(the mass of (A)) is 0.60-1.00, and (c) the monomeric glycolic acid content is 20-57 wt.%. (2) precipitating the crystals of glycolic acid from solution, and (3) separating the crystals from the solution (A).