Leveraging molybdenum sulfur compounds as catalysts for the synthesis of biobased poly(ethylene 2,5-furandicarboxylate) and recycling

Abstract

The uncovered potential of two safe dinuclear molybdenum complexes with non-rigid bidentate phosphinoyldithio formate ligands, each distinguished by their phosphorus atom substituents, was demonstrated for the first time in both the synthesis of poly(ethylene furan 2,5-dicarboxylate) (PEF) and its depolymerization. An in-depth evaluation of the reaction conditions, in terms of time and temperature, showcases the air and water stable handling of catalysts and their suitability to mediate PEF synthesis in a solvent-free, bulk polycondensation reaction, resulting in high efficiency and comparable properties as obtained with a benchmark titanium-based catalyst. Notably, excellent thermal properties and optically transparent polymers with over 89% transmittance in the visible region were achieved. Furthermore, these innovative molybdenum complexes were also able to efficiently prompt the chemical recycling of PEF through a glycolysis pathway under very mild conditions and in short reaction times.