Efficiently conversion of raw lignocellulose to levulinic acid and lignin nano-spheres in acidic lithium bromide-water system by two-step process.

Herein, acidic concentrated lithium bromide-water system was efficiently carried out to synthesize levulinic acid (LA) from raw lignocellulose by two-step treatment. Saccharification was processed in 1st step, and 80.96 wt% glucose and 85.60 wt% xylose were yielded based on their theoretical yield from poplar at 110 °C for 20 min. The hydrolysate after solid residual lignin (SRL) separation was converted into LA and furfural by thermal treatment (130 °C) in the 2nd step, where 67.0 wt% LA and 48.0 wt% furfural were yielded. The SRL in 1st step, with high hydrophobicity and uniform dispersity, was used to prepare lignin nanoparticles (LNPs), which showed tailored size (100-200 nm diameters) and morphology in solid or hollow structure with single hole. Additionally, the residue in 2nd step was suggested as biochar. So far, this study offered a simple pathway for utilization of raw lignocellulose in water system, resulting in high yields of LA and LNPs.