METHOD FOR PURIFYING LACTIDE

摘要

PROBLEM TO BE SOLVED: To provide a method for purifying a lactide by which a crude lactide is purified to afford the lactide having high optical purity of the D- or L-form with small energy consumption without causing thermal deterioration. SOLUTION: This method for purifying the lactide is carried out as follows. A solid crude lactide with≥80 mass% content of D-lactide or L-lactide based on the total amount of the D-lactide and the L-lactide as a raw material is charged into a charging port 3 for the raw material provided in the lower part of a cylindrical purification column 1 extending in the vertical direction and stirred while being raised with a stirrer 2 arranged in the purification column 1. The raw material is purified by countercurrent contact of a lowering melt of the D-lactide or L-lactide with the rising raw material in the purification column 1. The solid lactide after the purification is taken out as a product from a takeout port 4 provided in the upper part of the purification column 1. COPYRIGHT: (C)2005,JPO&NCIPI