Lignocellulose conversion via catalytic transformations yields biobased polyester from sawdust

Abstract Polyethylene terephthalate polyester represents the most common class of thermoplastic polymers widely used in the textile, bottling and packaging industries. Terephthalic acid and ethylene glycol, both of petrochemical origin, are polymerised to yield the polyester. However, an earlier report suggests replacement with 2-methoxyterephthalic acid provides a methoxy-polyester with equal properties. Currently, there are no established biobased synthetic routes towards methoxy-polyethylene terephthalate. Here we show a viable route to the polyester variant from various tree species involving three catalytic steps. We demonstrate that sawdust can be converted to valuable aryl nitrile intermediates through an efficient fluorosulfation-catalytic cyanation sequence (>90%), and then converted to methoxy-terephthalic acid by hydrolysis and oxidation. Our polymerisation results reveal similar decomposition and glass transition temperatures of methoxy-polyester in comparison with conventional polyester. This synthetic route towards a biobased methoxy-polyester is aligned with the general goal of polyester producing companies to replace this oil-based plastic with biobased alternatives.