Liquefaction of kraft lignin over the composite catalyst HTaMoO6 and Rh/C in dioxane-water system

A catalytic routine was developed for kraft lignin depolymerization in dioxane-water systems, in which the catalyst HTaMoO6 with strong Bronsted acidity and a hydrogenation catalyst (Rh/C) were employed simultaneously. The performance of the composite catalysts was tested in a series of experiments with various reaction temperatures, reaction time and catalyst ratios. Under the optimized conditions, a higher petroleum ether soluble fraction yield of 58.7% was obtained at 320 °C for 24 h. Besides, a higher liquid product yield of 95.6% was achieved at 290 °C for 2 h. Specially, the main compositions of the petroleum ether soluble fraction are monomers and dimers, which can be used as liquid fuel. These results demonstrated that the composite catalyst HTaMoO6-Rh/C can effectively catalyze the depolymerization of the kraft lignin into small molecule liquid fuel components.