| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a lactide having a high optical purity. SOLUTION: This method for producing a lactide having a high optical purity containing processes of (i) a process of heating lactic acid for concentrating the acid, (ii) a process of dehydrating the concentrated lactic acid while refluxint the same for forming a lactic acid oligomer, (iii) a process of removing lactic acid by depolymerization of the lactic acid oligomer in the presence of a catalyst, is constituted by performing the process (ii) under the following temperature conditions of 1st-3rd steps consecutively. the 1st step: liquid temperature 135±3 deg.C, the 2nd step: liquid temperature 150±3 deg.C, the 3rd step: liquid temperature 160±3 deg.C. |
