Effects of gamma-Valerolactone/H2O Solvent on the Degradation of pubescens for Its Fullest Utilization

Solvent-thermal conversion of biomass was promising for obtaining value-added chemicals. However, little was known about the interactions between solvents and biomass in the process, which hindered the effective utilization of biomass. The effects of gamma-valerolactone (GVL) and H2O on enhancing pubescens degradation via the cleavage of inter-and intramolecular linkages were studied. At 160 degrees C, H2O selectively promoted the cleavage of the intermolecular linkages by forming hydrogen bonds, making mainly contributions to hemicellulose dissolution, while GVL and H2O promoted lignin dissolution by forming hydrogen bonds with -OCH3 group of lignin. H2O promoted the cleavage of beta-(1,4)-glycosidic bonds in hemicellulose derived oligomers to xylose, while the oxygen in the ring of GVL might interact with hydroxyl groups of xylose unit to enhance the dehydration of xylose to furfural, whereas GVL with H2O promoted the depolymerization of lignin to oligomers mainly including beta-O-4' and beta-beta' linkages connecting to G and S units.