A novel liquid-liquid phase-change solvent with upper critical solution temperature for simultaneous pretreatment and separation of lignin, cellulose and hemicellulose from lignocellulosic biomass

Abstract

The compact dimensional aggregate structure and the complex chemical components of lignocellulose go against its high value utilization. The mixture of dilute hydrochloric acid and n-butanol, which had a characteristic of homogeneous phase at high temperature and phase separation at low temperature, was proposed for lignocellulosic hydrolysis and hydrolysates separation. The results showed that lignocellulose was hydrolyzed under the synergy effect of hydrochloric acid and n-butanol in homogeneous condition, and hemicellulose and lignin hydrolysates were transferred automatically into dilute hydrochloric acid phase and n-butanol phase during the phase separation of the solvent after pretreatment, respectively. N-butanol accelerated lignin hydrolysis and protected β-O-4 linkage within lignin during the pretreatment. Meanwhile, the cellulose within solid phase product from the pretreatment was of high crystallinity, and its glucose yield in enzymatic saccharification at 48 and 72 h were 73.5% and 97.3%, respectively. This study provides a new method for lignocellulose hydrolysis and hydrolysates separation, and lays a theoretical foundation for lignocellulosic utilization of all component.