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Lipase-catalyzed enantioselective synthesis of (R,R)-lactide from alkyl lactate to produce PDLA (poly D-lactic acid) and stereocomplex PLA (poly lactic acid)

Paper ID Volume ID Publish Year Pages File Format Full-Text
23370 43439 2013 7 PDF Available
Title
Lipase-catalyzed enantioselective synthesis of (R,R)-lactide from alkyl lactate to produce PDLA (poly D-lactic acid) and stereocomplex PLA (poly lactic acid)
Abstract

•Among many tested lipases and proteases only CALB catalyzed the synthesis of D-lactide from alkyl lactate.•Enatiopurity of produced D-lactide was over 99.5%.•Removal of methanol using molecular sieve was critical to increase the yield of D-lactide.

R-lactide, a pivotal monomer for the production of poly (D-lactic acid) (PDLA) or stereocomplex poly (lactic acid) (PLA) was synthesized from alkyl (R)-lactate through a lipase-catalyzed reaction without racemization. From among several types of lipase, only lipase B from Candida antarctica (Novozym 435; CAL-B) was effective in the reaction that synthesized (R,R)-lactide. Enantiopure (R,R)-lactide, which consisted of over 99% enantiomeric excess, was synthesized from methyl (R)-lactate through CAL-B catalysis. Removal of the methanol by-product was critical to obtain a high level of lactide conversion. The (R,R)-lactide yield was 56% in a reaction containing 100 mg of Novozym 435, 10 mM methyl (R)-lactate and 1500 mg of molecular sieve 5 A in methyl tert-butyl ether (MTBE). The important monomer (R,R)-lactide that is required for the production of the widely recognized bio-plastic PDLA and the PLA stereocomplex can be obtained using this novel synthetic method.

Keywords
(R,R)-lactide; Alkyl (R)-lactate; Lipase; Novozym 435; Molecular sieve
First Page Preview
Lipase-catalyzed enantioselective synthesis of (R,R)-lactide from alkyl lactate to produce PDLA (poly D-lactic acid) and stereocomplex PLA (poly lactic acid)
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 168, Issue 2, 20 October 2013, Pages 201–207
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering