PRODUCTION OF HIGHLY CONCENTRATED AQUEOUS SOLUTION OF GLYCOLIC ACID

PURPOSE:In obtaining the titled compound useful as a detergent for various metals by hydrolyzing monochloroacetic acid as an raw material, to improve concentration, by hydrolyzing the raw material with a specific concentration under a specific condition, removing a precipitated salt through two processes and advantageously desalting the resultant product. CONSTITUTION:In an aqueous medium, monochloroacetic acid as a raw material is made into 30-60wt% concentration and hydrolyzed with 0.9-1.5mol, preferably 1.0-1.3mol based on 1mol monochloroacetic acid of an alkali metallic base such as caustic soda, etc., at 70-130 deg.C, preferably 80-120 deg.C. A precipitated salt is removed by filtration by adding a mineral acid or without adding it, 85-95wt% water of the filtrate is concentrated under reduced pressure, the concentrate is incorporated with 2-7 times as much a hydrophilic organic solvent as the concentrate, a precipitated salt is removed, the hydrophilic organic solvent is removed by distillation, then the resultant substance is blended with water to adjust glycolic acid to 50-80wt% concentration and it is desalted by an ion exchange resin, to give the aimed compound.