| 摘要 |
PROBLEM TO BE SOLVED: To provide an economical and efficient purification method of a crude dimeric cyclic ester of anα-hydroxycarboxylic acid. SOLUTION: The purification method of a dimeric cyclic ester of anα-hydroxycarboxylic acid comprises adding a specific high boiling point polar organic solvent to a crude dimeric cyclic ester of anα-hydroxycarboxylic acid, heating at≥230°C under normal pressure or a reduced pressure so that the dimeric cyclic ester of anα-hydroxycarboxylic acid is made to be a uniform solution with the high boiling point polar organic solvent, and continuing heating on a state of a liquid phase of the uniform solution to distil the dimeric cyclic ester of anα-hydroxycarboxylic acid with the high boiling point polar organic solvent, and recovering the dimeric cyclic ester from the distillate. COPYRIGHT: (C)2009,JPO&INPIT
|
