Sugar-Based Polyesters: From Glux-Diol Synthesis to Its Enzymatic Polymerization

TL;DR

Researchers developed a new way to make biobased polyesters using a sugar-derived compound and enzyme-based polymerization.

Contribution

A new purification method and enzymatic polymerization process for producing biobased polyesters from glux-diol.

Findings

Glux-diol was synthesized efficiently using protection, esterification, and reduction steps.

Enzymatic polymerization produced oligomers with molecular weights between 900 and 2200 g mol–1.

The resulting polyesters showed thermal stabilities between 391 and 419 °C.

Abstract

This work details
the synthesis of 2,4:3,5-di-O-methylene-d-glucitol (glux-diol), a bicyclic acetal derivative
of d-glucose obtained from d-glucono-1,5-lactone,
and also explores its subsequent polymerization to produce biobased
polyesters. Key steps for the synthesis of glux-diol are (i) protection
with paraformaldehyde, (ii) Fischer esterification, and (iii) reduction
with lithium aluminum hydride (LiAlH4). A new purification
method was developed to effectively remove inorganic salt byproducts,
which can hinder polymerization. The sugar-based monomer was then
copolymerized with C4–C10 dimethyl esters using Candida antarctica lipase B as a biocatalyst in Cygnet
2.0, a green, high-boiling solvent. The biocatalytic polycondensation
produced oligomers with number-average molecular weights (M
n) between 900 and 2200 g mol–1. These materials exhibited thermal stabilities ranging from 391
to 419 °C, with the specific temperature depending on the molecular
weight, degree of polymerization, and the carbon chain length of the
chosen diester. Overall, this integrated approach, which combines
efficient sugar functionalization with biocatalysis, offers a promising
pathway for the synthesis of novel biobased polyesters.

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