La(III)-Catalyzed Depolymerization of Poly(L-Lactic Acid) Yielding Chiral Lactates
Biomass-based polymers can be a valuable resource of chiral compounds through depolymerization. [La(acac)3]-catalyzed (1 mol%) depolymerization of poly(L-lactic acid) (PLLA) (Mw = 1.58 × 105) pellets in MeOH at 90 °C for 3 h produced methyl L-lactate in >99% yield (96% ee). When powdered PLLA is...
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Published in | Bulletin of the Chemical Society of Japan Vol. 96; no. 12; pp. 1324 - 1330 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
The Chemical Society of Japan
15.12.2023
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Subjects | |
Online Access | Get full text |
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Summary: | Biomass-based polymers can be a valuable resource of chiral compounds through depolymerization. [La(acac)3]-catalyzed (1 mol%) depolymerization of poly(L-lactic acid) (PLLA) (Mw = 1.58 × 105) pellets in MeOH at 90 °C for 3 h produced methyl L-lactate in >99% yield (96% ee). When powdered PLLA is used, this reaction can be achieved at 40 °C for 6 h in >99% (95% ee). PLLA is depolymerized in EtOH by La(NO3)3·6H2O or [Fe(acac)3] (1 mol%) at 135 °C for 4 h to give ethyl L-lactate in 86% (96% ee) and 87% yield (96% ee), respectively. The depolymerization by [La(acac)3] (5 mol%) in HNEt2 at 150 °C for 3 h gives N,N-diethyllactamide in 85% but the enantiomeric excess decreases to 27% ee. |
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ISSN: | 0009-2673 1348-0634 |
DOI: | 10.1246/bcsj.20230183 |