Alcoholysis of High-Solid xylose residue for methyl levulinate preparation and its kinetics

Achieving the efficient biomass alcoholysis to methyl levulinate (ML) under high solid content conditions and establishing its kinetic model are crucial, but remain challenging. Here, the alcoholysis of microcrystalline cellulose (MC) and xylose residue (XR) to ML under high solid content conditions using CuSO₄ as a catalyst was reported. High yield (34.96 wt%) and concentration (41.48 g/L) of ML from MC alcoholysis are achieved under the optimal conditions. Meanwhile, the yield and concentration of ML from XR alcoholysis can reach 26.73 wt% and 31.72 g/L, respectively. The alcoholysis pathways of MC and XR are proposed. A mixed model consisting of a shrinking core model and a pseudo-first-order kinetic model was established to elucidate the alcoholysis behavior of biomass. The generation of glucose is the rate-limiting step of the alcoholysis process, and there is no significant dependence between the activation energies of main reactions and the solid content of biomass.