Deconstruction of biomass into lignin oil and platform chemicals over heteropoly acids with carbon-supported palladium as a hybrid catalyst under mild conditions

In this work, near-complete conversion of lignocellulosic biomass and high products yields were achieved through catalytic transfer hydrogenolysis (CTH) in isopropanol using a heteropoly acid SiW12 synergistic with Pd/C catalyst at a relatively mild condition. The performances of various heteropoly acids and catalytic conditions were extensively examined. The results confirmed that SiW12 exhibited the highest activity on disrupting C–C linkages and C-O linkages than H2WO4, PW12, and PMo12. 34.91 wt% and 43.55 wt% monophenols were achieved for hydrogenolysis of bagasse and eucalyptus, respectively, at their optimal temperature for 5 h. Characterization studies on the lignin oil revealed that the notable structural changes were observed including the breaking of the side chain alkyl-aryl ether bonds and glycosidic bonds, while methoxyl groups were retained. Additionally, particle size of feedstock also has significant impact on the distribution and yields of the monophenols.