A kinetic study of triacetin hydrolysis under microwave heating in aqueous high-temperature media

Transforming agri-food waste into valuable bio-based materials is essential to achieving a circular economy. However, given the structural complexity of these materials, which is often defined by intricate three-dimensional architectures, systematic investigation using model compounds is required. In this context, efficient ester bond hydrolysis is a critical step in elucidating and optimising depolymerisation pathways in biomass-derived bio-polyesters. This study investigates the cleavage of ester bonds using triacetin as a model compound within a microwave-assisted hydrolysis framework, evaluated as a potential technique for process intensification. A comparative kinetic study was done under different time and temperature conditions. Experimental data were evaluated against several kinetic models; the most accurate correlation was achieved using an irreversible autocatalytic mechanism catalysed by H 3 O + ions. At the highest temperature, 230°C, almost complete conversion of triacetin to glycerol was achieved in 15 minutes without adding any catalyst. Although there is no evidence of any non-thermal effect caused by microwaves, the fast heating ramp and homogeneous volumetric heating enabled an intensified, catalyst-free hydrolysis of triacetin that can be described with a simple sequential kinetic model, providing practical parameters for process design and a basis for extending this approach to more complex biomass polyesters (e.g., cutin)