| abstract |
A method of purifying a cyclic ester, the method including: granulating a crude cyclic ester, an average particle size of resulting granules being 0.05-1.00 mm; adding the granules to 0-4° C. water to yield a mixture, a mass ratio of the water to the granules being (0.5-2):1; stirring the mixture, and performing solid-liquid separation on the mixture; repeating the stirring and solid-liquid separation for 1-4 times, to yield a purified cyclic ester; drying the purified cyclic ester at 0-4° C. and at an absolute pressure of less than or equal to 10 pascal for 4-6 hours, and continually drying the purified cyclic ester at 40-60° C. and at an absolute pressure of less than or equal to 5 pascal for 1-2 hours. |