PRODUCTION OF POLYLACTONE

PURPOSE:To obtain the titled compound by a simple method without requiring photochlorination, by reacting ethylene trifluoride with formaldehyde and water in the presence of sulfuric acid, distilling the reaction mixture in the presence of water at a specific temperature and polymerizing a distillate. CONSTITUTION:Ethylene trichloride is reacted with formaldehyde and water in a molar ratio of preferably 1:1-1.5:1-5 at 45-60 deg.C in the presence of preferably >=95wt% sulfuric acid. Then, the formed reaction mixture is distilled in the presence of water at 110-180 deg.C to give distillate containing alpha-chloroacrylic acid, which is usually condensed into a liquid state and fed to a reactor for polymerization. It is polymerized by the action of a radical polymerization catalyst or ionic polymerization catalyst preferably at 70-100 deg.C, to give the aimed polylactone. The compound is important as a precursor for a poly-alpha- hydroxyacrylic acid salt useful as a metallic blocking agent, detergent builder, etc.