| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently producing a lactide having a purity sufficient as a starting raw material for polylactic acid. SOLUTION: The purified lactide is produced by condensing lactic acid under reduced pressure to produce a lactic acid oligomer, depolymerizing the obtained lactic acid oligomer to synthesize crude lactide and purifying the obtained crude lactide, wherein the lactic acid concentration in the purified lactide is determined by near-infrared spectroanalysis and the repetition of the purifying operation is terminated or the purification condition is controlled according to the determination result. COPYRIGHT: (C)2011,JPO&INPIT |
