A novel deep eutectic solvent-methyl isobutyl ketone biphasic system for the catalytic conversion of wheat straw to furfural and recovery of cellulose and lignin

Abstract

Currently, the conversion of lignocellulosic biomass into furfural using deep eutectic solvents (DES) as the solvent and catalyst has many shortcomings including low furfural yields and inefficient resource utilization. To address these issues, a novel effective DES-methyl isobutyl ketone (DES-MIBK) reaction system was designed and used to catalyze the transformation of wheat straw to furfural and separate/recover cellulose and lignin in this work. The results showed that the DES-MIBK system could significantly improve furfural yield of up to 76.2 % at a mild condition (at 100 °C for 60 min). Furthermore, cellulose and lignin were fractionated and recovered from the reaction residues and the lignin yield reached 68.7 %. Moreover, the recovered cellulose exhibits high crystallinity (CrI=67.7 %). and the obtained lignin also has good uniformity with a small polydispersity index (PDI=2.36), and the results of FT-IR and 2D NMR indicated that the obtained lignin retains its fundamental structure. This research highlights that the innovative DES-MIBK system has a high-efficient in the production of furfural and the recovery of lignin and cellulose, which could provide a novel strategy for the high-value and sustainable application of lignocellulose biomass.