Hydrogenolysis of lignin into phenols over a high dispersed Pd supported on WO_2.72

The depolymerization of lignin into aromatic monomers with high yield is the bottleneck of high valued utilization of lignin. In this work, a highly dispersed Pd supported on WO_2.72 (Pd/WO_2.72) catalyst was prepared for efficient hydrogenolysis lignin. The highly dispersed Pd, high specific surface area, high content of acidic sites, and hydrogen spillover of Pd/WO_2.72 improved the depolymerization efficiency of lignin. In addition, the depolymerized products were alkylated with the reaction solvent to prevent monomers from re-polymerizing, thus further enhancing aromatic monomers yield. Under 320 ℃, 6 h, bio-oil and aromatic monomers yield reached 77.67 wt% and 28.80 wt%, respectively. Among the aromatic monomers, the tert-butyl group substituted products accounted for 65.71%, of which 77.1% were methoxy-free phenols. It was found that the bio-oil had a calorific value of 38.13 MJ/kg and an IC₅₀ value of 43 mg/L, showing their potential applications as fuels or antioxidant additives.