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丙交酯是聚乳酸生产过程中重要的中间体。制备不同SnCl_2摩尔分数的Br?nsted-Lewis双酸性离子液体([HSO_3-bmim]Cl-SnCl_2),将其用作通过预聚路径法合成L-丙交酯的催化剂。研究离子液体中SnCl_2含量对催化活性的影响。考察催化剂用量、反应温度和反应时间对粗丙交酯产率的影响。结合反应残渣的表征结果,提出可行的反应残渣和离子液体催化剂的循环利用方案,结果表明:经过3轮的循环利用,催化剂活性基本不变,基于添加的L-乳酸计算的粗丙交酯产率高达90.99%~92.64%。
Lactide is an important intermediate in polylactic acid production. Br? Nsted-Lewis bisacid ionic liquids ([HSO_3-bmim] Cl-SnCl_2) with different molar fractions of SnCl_2 were prepared and used as catalysts for the synthesis of L-lactide by the prepolymerization route. The effect of SnCl 2 content in ionic liquid on the catalytic activity was studied. The effect of catalyst amount, reaction temperature and reaction time on the yield of crude lactide was investigated. Combined with the characterization results of the reaction residue, a feasible recycling scheme of the reaction residue and the ionic liquid catalyst is proposed. The results show that after 3 cycles of recycling, the catalyst activity basically remains unchanged. Based on the L-lactic acid added crude lactide Rate up to 90.99% ~ 92.64%.