Selective, Green Synthesis of Six-Membered Cyclic Carbonates by Lipase-Catalyzed Chemospecific Transesterification of Diols with Dimethyl Carbonate
作者:Sang-Hyun Pyo、Rajni Hatti-Kaul
DOI:10.1002/adsc.201100822
日期:2012.3.16
A facile and green synthesis of six‐membered cyclic carbonates, the potential monomers for isocyanate‐free polyurethanes and polycarbonates, was achieved by transesterification of diols with dimethyl carbonate catalyzed by immobilized Candida antarctica lipase B, Novozym®435, followed by thermal cyclization in a solvent‐free medium. The difference in the chemospecificity of the lipase for the primary
通过固定化南极假丝酵母催化二醇与碳酸二甲酯的酯交换反应,实现了六元环状碳酸酯(不含异氰酸酯的聚氨酯和聚碳酸酯的潜在单体)的简便,绿色合成。脂肪酶B,Novozym®435,然后在无溶剂介质中热环化。脂肪酶对伯,仲和叔醇作为酰基受体的化学特异性的差异可用于以高收率获得高度化学选择性的环状碳酸酯的合成。在与二醇的脂肪酶催化反应中,产物中含有几乎相等比例的一碳酸酯和二碳酸酯,以及带有两种伯醇的1,3-丙二醇,含有更高比例的一碳酸酯与具有伯醇的1,3-丁二醇。仲醇,主要是单碳酸酯,以及具有伯醇和叔醇的3-甲基-1,3-丁二醇。在90°C热处理形成的环状碳酸酯的化学专一性与一碳酸根的比例密切相关。使用3-methyl-1时,环状碳酸酯的产率为99.3%,