乙交酯的合成

Synthesis of Glycolide

以煤法制乙二醇(EG)工艺中的副产物羟基乙酸(PGA)为原料,先预聚成低相对分子质量聚羟基乙酸再解聚制备乙交酯。研究发现,解聚升温速率对乙交酯的收率有重要影响,同时考察了各反应条件对乙交酯收率的影响。结果表明,在聚合温度180℃,加入催化剂w(Sb2O3)=0.75%(以低聚物PGA质量计),以15℃/min的速率升至290℃有最佳解聚效果,粗产物乙交酯的收率高达87.5%,3次重结晶后质量分数高于99.9%,收率为78.0%,并通过红外光谱、核磁共振氢谱等对产物乙交酯进行了表征。

Polyglycolic acid（PGA） has been prepared from glycolic acid（GA） which is the by-product of the coal chemical industry,and glycolide has been synthesized from PGA by depolymerization.It is found that heating rate has a great influence on the yield of glycolide.The effects of reaction conditions on the yield of glycolide have been investigated and the optimized conditions are as follows：the polymerization temperature is 180 ℃,Sb2O3 is used as the catalyst with a mass fraction of 0.75%,and the depolymerization temperature is 290 ℃ with a rising rate of 15 ℃/min.Under the optimized conditions,the crude yield of glycolide can reach 87.5%.After three times of recrystallization,the purity is higher than 99.9% and the yield is 78.0%.The obtained glycolide has been identified by IR and 1HNMR.