丙交酯提纯新工艺研究

Study on new purification process of lactide

采用双溶剂萃取工艺对粗丙交酯进行提纯,考察了溶剂种类、提纯温度、提纯时间、溶剂添加量及溶剂添加顺序五个因素对双溶剂萃取提纯过程的影响。实验结果表明,以水和低碳数的醇类为溶剂、先加水后加有机溶剂、n(丙交酯)∶n(水)∶n(溶剂)=1∶(1~0.67)~(1~0.5)、萃取温度5~40℃,可得到纯度为97.0%(w)、收率不低于77.0%的丙交酯;经熔融结晶精制所得产品的各项指标与精馏工艺相当,采用溶剂和水的双溶剂萃取作为粗丙交酯预处理工艺,可取代精馏预处理提纯过程,且具有更好的提纯效果。

A process of double solvent extraction was used for purification of crude lactide.The factors affecting double-solvent extraction were investigated,such as solvent type,purification temperature,purification time,solvent amount and sequence of solvent addition.The experimental results show that under the conditions of using water and some low carbon number alcohol as solvents,adding organic solvent after water,n(lactide) ∶ n(water) ∶ n(solvent) 1 ∶(1-0.67) ∶(1-0.5),and extraction temperature 5-40 ℃,the purity of the pretreated lactide is 97.0%,the yield is more than 77.0%.The quality of the product refined by melting crystallization is similar with that by distillation.The pretreatment process of crude lactide by double solvent extraction with water and organic solvent can replace that by distillation,and has a better purification result.