【摘要】 以D,L-乳酸为原料,在催化剂存在下通过脱水环化合成D,L-丙交酯,研究了反应过程中催化剂用量、脱水温度及稀释剂等因素对D,L-丙交酯产率的影响。用重结晶法对粗产物进行纯化,制备出高产率、高纯度的D,L-丙交酯。实验结果表明,采用二丁基氧化锡为催化剂,最佳催化剂用量(质量分数)为1 5%,最佳脱水温度为140℃,且在反应中加入稀释剂可以显著提高D,L-丙交酯的粗产率;乙醇是理想的重结晶溶剂,粗产物经多次纯化后,可获得总产率达37 3%的纯D,L-丙交酯。更多还原

【Abstract】 D,L-lactide was prepared from D,L-lactic acid with dibutyltin oxide as catalyst.Effects of catalyst quantity,dehydration temperature as well as addition of diluent on yield of lactide were studied.Crude lactide was purified through recrystallization.Lactide with high yield and high purity was obtained and identified by melting point,IR and ()~1H NMR spectrum.The proper amount of catalyst used was 1.5%,proper dehydration temperature was 140 ℃,and addition of diluent to reaction system at depolymerization stage could increase yield of crude lactide obviously(yield of crude lactide was up to 70.1%).Ethanol was an appropriate solvent for recrystallization,with which the total yield of purified lactide reached 37.3%.IR and ()~1H NMR spectrum proved the structure of the expected lactide.更多还原