Selective, Green Synthesis of Six-Membered Cyclic Carbonates by Lipase-Catalyzed Chemospecific Transesterification of Diols with Dimethyl Carbonate
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 (R) 435, followed by thermal...
| Published in: | Advanced Synthesis & Catalysis |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
John Wiley & Sons Inc.
2012
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| Subjects: | |
| Online Access: | https://lup.lub.lu.se/record/2591313 https://doi.org/10.1002/adsc.201100822 |
| Summary: | 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 (R) 435, followed by thermal cyclization in a solvent-free medium. The difference in the chemospecificity of the lipase for the primary, secondary and tertiary alcohols as acyl acceptors was utilized to obtain a highly chemoselective synthesis of the cyclic carbonate in high yield. In the lipase-catalyzed reaction with diols, the product contained almost equal proportions of mono- and di-carbonates with 1,3-propanediol having two primary alcohols, a higher proportion of mono-carbonate with 1,3-butanediol having a primary and a secondary alcohol, and mainly mono-carbonate with 3-methyl-1,3-butanediol having a primary and a tertiary alcohol. The chemospecificity of cyclic carbonates formed by thermal treatment at 90 degrees C was closely related to the proportion of mono-carbonate. The yield of cyclic carbonate was 99.3% with 3-methyl-1,3-butanediol, 85.5% with 1,3-butanediol, and 43.2% with 1,3-propanediol. |
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