C_(1～5)醇乳酸酯及丙交酯制备的初步研究

Preparation of Lactates of C_1-C_5 alcohols and Further Prepering Lactide from Them

用C_(1～5)醇酯化D,L-乳酸制得相应的乳酸酯,其中用C_(4～5)醇酯化乳酸不用带水剂,产率可达80％以上,由D,L-乳酸酯制丙交酯会生成等量的外消旋与内消旋体。外消旋丙交酯为目标产物,内消旋丙交酯可回收作原料。由此计算外消旋丙交酯单程产率将不大于50％,实验中除乳酸甲酯外,乳酸酯单程消耗率和丙交酯单程产率分别为26％～38％和22％～35％。

C1-5 alcohols esterified D,L- lactic acid to form corresponding lactates. Among them C4_5 alcohols yielded exceeding 80% without use of an entraning agent. Preparing lactide from D. L - lactates could produce equal amounts of ra-cemic - and meso - isomers. The racemic - latide was the target product, whereas the meso - one could be recovered as a raw material. Therefore it is calculated that the single pass yield of racemic - lactide would be not higher than 50% . In the experiments the actual single pass yields of racemic - lactide and the single pass consumption rates of lactates reached 22% - - 35% and 26% -38% respectively, except that conducted with methyl lactate.