Solvolytic Conversion of Biorefinery Lignin to Value-Added Products

Next generation biorefineries will produce a significant amount of lignin-enriched residues, which are currently just burnt or underutilized. Therefore, new lignin valorization strategies targeting biorefinery lignin streams are important from technoeconomic standpoint. Herein, we show the solvolytic depolymerization of lignin obtained from ionic liquid (IL) pretreatment/saccharification process into low molecular weight compounds. Joint Bioenergy Institute (JBEI) has recently developed one-pot IL pretreatment / saccharification process using biocompatible and bio-derived ILs, which was found to be effective for biomass pretreatment. Residual lignin recovered after one-pot process was subjected to a depolymerization reaction using a Parr reaction with hydrogen donor solvent. The effects of reaction parameters, including reaction temperature (250 ~ 300 °C), time (1 ~ 4 hrs) and catalyst (Ru/C) on depolymerization behavior of lignin were explored. Mass balance analysis shows that approximately 70 % liquid is obtainable from biorefinery lignin. In-depth analysis will be performed to characterize the final products, which will include GC, GPC and NMR. This study will help to provide insights for developing effective depolymerization pathway of biorefinery lignin.