| 摘要 |
PROBLEM TO BE SOLVED: To obtain a pentaerythritol poly(thioglycolate) useful as a monomer for plastic lens, a raw material for polyurethane resin, etc., by carrying out dehydrative esterification reaction of thioglycolic acid and pentaerythritol in the presence of an acidic catalyst using an inert solvent having a specific dielectric constant and separable from water. SOLUTION: The objective compound is produced by the dehydrative esterification reaction of thioglycolic acid and pentaerythritol in the presence of an acidic catalyst (e.g. sulfuric acid) using an inert solvent having a dielectric constant of 3-15 and separable from water, preferably an inert solvent forming an azeotropic mixture with water (e.g. dichloroethane). The esterification reaction temperature is preferably 60-100 deg.C. The amount of water removed from the system by azeotropic dehydration is preferably >=93 wt.%. Solvent of a washed pentaerythritol poly(thioglycolate) solution is removed b heating at 50-120 deg.C under a reduced pressure of preferably 200-5 torr (27-0.7 kPa). |
