(655c) Direct Production of Renewable Polyesters with High Glass Transition from Lignocellulosic Biomass

The need for sustainable polymers has driven the development of an array of chemical and biological pathways to potential monomers derived from renewable sources^1–5. Despite decades of innovation, low conversion efficiencies from raw lignocellulosic feedstocks persist⁶. Here we present a new class of renewable polymer precursors that can be produced in a single step from the hemicellulose fraction of lignocellulosic biomass in high yields using a previously described aldehyde-facilitated biomass pretreatment^7–9. By leveraging the use of aldehydes with different functionalities, we can install targeted functional handles onto both sides of the hemicellulose-derived xylose—creating a tricyclic, difunctional structure that presents as a potential renewable monomer for high-glass transition bioplastic synthesis. As the functional backbone of the aldehyde in our process can be varied, this strategy could unlock a new class of renewable polymers that can be produced in a single step from lignocellulosic biomass. These polymer precursors can also be produced directly produced from xylose, providing a direct route to high volume production of these bioplastics, circumventing the immediate need for a biorefinery. Here, we demonstrate the use of a carboxylic acid-functionalized aldehyde (glyoxylic acid) to produce a novel, tricyclic, diacid precursor in a solventless reaction directly from xylose up to 93% yield. Mechanically useful, high molecular-weight polyesters (50-180 kDa) with glass transition temperatures ranging from 76-134°C are then synthesized via melt condensation with commercially-relevant zinc and antimony-based catalysts (<100ppm) using a range of aliphatic diols. Chemical recycling of these polymers via low temperature hydrolysis and alcoholysis is demonstrated along with hydrolytic stability studies. As a proof-of-concept, the tricyclic, diacid monomer is produced directly from lignocellulosic biomass in concert with glyoxylic acid stabilized lignin and highly digestible, cellulose-rich solids. Finally, a techno-economic analysis generated using Aspen Plus is presented demonstrating the economical production of the dimethyl ester monomer from xylose.

References:

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