In order to utilize lignin residue from the pretreatment of empty fruit bunch (EFB) and crude glycerol
from biodiesel production, lignin residue was solvothermally liquefied using crude glycerol to produce
lignol. The optimal liquefaction conditions for lignol production were determined to be 10% biomass
loading, 5% acid loading, a liquefaction temperature of 170 8C, and a liquefaction time of 120 min. The
biomass conversion at the optimal conditions was 47.9%. The lignols possess hydroxyl number of
1649.3 mg KOH/g and acid number of 8.4 mg KOH/g. Fourier transform infrared spectroscopy revealed
that the lignol was suitable for biopolyurethane synthesis.