Effects of various solvents on the liquefaction of biomass to produce fuels and chemical feedstocks

The liquefaction of pinewood in the presence of various solvents (water, acetone and ethanol) was studied so as to investigate the solvent effects on the biomass liquefaction process. Experiments were conducted in an autoclave in the conditions of temperature range 523–723 K, starting pressure 1 MPa, reaction time 20 min, biomass 10 g and solvent 60 g, respectively. The liquid products and solid residues were characterized by GC–MS and FTIR. The results showed that the liquefaction products were greatly affected by the solvent type. With acetone as extraction agent, 4-methyl-1,2-benzenediol was one of the major compounds, while ethanol favored the formation of (E)-2-methoxy-4-(1-propenyl)-phenol and water significantly narrowed the products distribution. Among the tested solvents, acetone had the highest conversion rate, while the highest oil yield reached 26.5% at 473 K in ethanol. The FTIR analysis showed that cellulose liquefaction speed in water preceded in acetone and ethanol, and the solid residue consisted of solid carbon and a little amount of lignin fragments at 723 K.