A Green DES for the fractionation of lignocellulosic biomass

Abstract In this study, a DES system composed of benzoic acid (BA) and choline chloride (ChCl) was fabricated, and successfully applied to the lignocellulose fractionation. The DES has low toxicity and little pollution. In this system, 67.8% of lignin and 91.2% of hemicellulose were removed, leaving 95.8% of cellulose intact as solid residue. Due to the removal of the amorphous components, crystallinity of CRS substantially increased from 55.6–68.6%, and CRS was used as feedstock for nanocrystalline cellulose preparation with excellent properties. The results showed that the obtained lignin had similar properties to MWL by GPC, FT-IR, 2D-NMR and TGA. A high-purity lignin rich in G units was recovered with a well-preserved structure, which has β-O-4 linkage content up to 53.01%, low molecular weight, low polydispersity (1.99). This study demonstrated that BA is suitable for DES design with excellent properties on lignin extraction, and this promising DES enable efficient pretreatment for economically feasible biomass conversion.