Chemical synthesis of perfectly isotactic and high melting bacterial poly(3-hydroxybutyrate) from bio-sourced racemic cyclic diolide.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29891896.
- Also identified by DOI 10.1038/s41467-018-04734-3 and PMC identifier 5995816.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Bacterial poly(3-hydroxybutyrate) (P3HB) is a perfectly isotactic, crystalline material possessing properties suitable for substituting petroleum plastics, but high costs and low volumes of its production are impractical for commodity applications. The chemical synthesis of P3HB via ring-opening polymerization (ROP) of racemic β-butyrolactone has attracted intensive efforts since the 1960s, but not yet produced P3HB with high isotacticity and molecular weight. Here, we report a route utilizing racemic cyclic diolide (rac-DL) derived from bio-sourced succinate. With stereoselective racemic catalysts, the ROP of rac-DL under ambient conditions produces rapidly P3HB with perfect isotacticity ([mm] > 99%), high melting temperature (T<sub>m</sub> = 171 °C), and high molecular weight (M<sub>n</sub> = 1.54 × 10<sup>5</sup> g mol<sup>-1</sup>, Đ = 1.01). With enantiomeric catalysts, kinetic resolution polymerizations of rac-DL automatically stops at 50% conversion and yields enantiopure (R,R)-DL and (S,S)-DL with >99% e.e. and the corresponding poly[(S)-3HB] and poly[(R)-3HB] with high T<sub>m</sub> = 175 °C.
Medical subject headings
- 3-Hydroxybutyric Acid
- Biocompatible Materials
- Hydroxybutyrates
- Polyesters
- Stereoisomerism