Catalytic conversion of chitin biomass coupling the acetylation of glycerol without additives

Abstract

The efficient upcycling of biowaste into high-value chemicals is a key step toward sustainable biomass utilization. In this study, we report the tandem valorization of chitin and glycerol biowaste using solid acid catalysts without the use of homogeneous additives. The process integrates mechanocatalytic hydrolysis of chitin with subsequent hydrothermal treatment to produce 5-hydroxymethylfurfural (5-HMF), while simultaneously utilizing acetic acid, generated from chitin hydrolysis, to convert glycerol into valuable glycerol acetates. We systematically investigated the effects of solvent systems and catalyst properties on reaction selectivity and product evolution, revealing that the precise control of solvent composition and reaction time play a crucial role in optimizing product yield. By replacing conventional dimethyl sulfoxide (DMSO) with greener solvents, we achieved comparable yields at lower temperatures and shorter reaction times, improving both efficiency and sustainability. Moreover, mechanistic studies identified surface carboxyl groups on carbon-based catalysts as the primary Brønsted acid sites responsible for chitin depolymerization in mechanocatalytic process and 5-HMF formation in the hydrothermal dehydration reaction. The strong Brønsted acid sites on the solid catalyst efficiently contribute to both 5-HMF formation and glycerol acetylation in this one-pot reaction. These findings offer new insights into biomass valorization and provide a foundation for designing greener and more efficient catalytic processes for biowaste upcycling.