Effect of Choline-Based Deep Eutectic Solvent Pretreatment on the Structure of Cellulose and Lignin in Bagasse

Deep eutectic solvents (DESs) is a newly developed green solvent with low cost, easy preparation and regeneration. Because of its excellent solubility swelling effect in lignocellulose, it has received widespread attention recognition. In this study, choline-based deep (DESs)—choline chloride-urea (CC-U), choline chloride-ethylene glycol (CC-EG), chloride-glycerol (CC-G), chloride-lactic acid (CC-LA), chloride-oxalic (CC-OA)—were used to extract separate bagasse. The effects hydrogen bond donors on lignin separation the fiber structure were investigated. All five DESs could dissolve from bagasse; acidic exhibited higher than basic DESs. CC-OA effectively separated hemicellulose. CC-LA showed weaker ability CC-OA. CC-G, CC-EG, CC-U more inclined selectively crystalline cellulose II was retained after DES pretreatment. Acidic improved crystallinity bagasse fiber; crystallinities for pretreatment 62.26% 61.65%, respectively. dissolved mainly syringyl lignin. CC-U, CC-LA, contained small amount guaiacyl