Efficient depolymerization of lignin in supercritical ethanol by a combination of metal and base catalysts

Abstract This study investigates the use of combination of metal and solid-base catalysts for effective depolymerization of lignin into monophenol-rich bio-oil in supercritical ethanol through a synergy of base-catalyzed solvolysis and metal-catalyzed hydrogenolysis. The results showed that a combined catalyst of Ru/C and MgO/ZrO2 resulted in a significant decrease in the molecular weight of bio-oil, an increase in the yield of phenolic monomers, and the improved deoxygenation degree of bio-oil compared to the single catalyst condition. The synergic role of metal and base catalysts during lignin depolymerization was examined through comprehensive analysis of reaction products.