Dissolution mechanism enabling efficient lignin and hemicellulose separation in CrCl3-catalyzed ethanol pretreatment

As a green and efficient pretreatment method, CrCl 3 -catalyzed ethanol pretreatment was employed to depolymerize poplar at various reaction times (5, 10, 20, 30, 50, and 70 min) and temperatures (160, 170, 180, 190, and 200°C) to effectively remove lignin and hemicellulose, thus improving the subsequent enzymatic saccharification efficiency of cellulose. The maximum lignin and hemicellulose removal yields of 94.51 % and 94.78 %, respectively, were achieved when pretreated at 200°C for 20 min. Furthermore, The CrCl 3 -ethanol pretreatment was found to have low dissolution activation energies (18.03 kJ/mol for lignin and 24.15 kJ/mol for hemicellulose) through pseudo-first-order kinetic modeling with ’potential solubility’ integration, demonstrating an energy-efficient synergistic effect conducive to reaction progression. Finally, combining density functional theory (DFT) from the molecular level clarified that hydrogen bonding and conjugated effect of CrCl 3 –ethanol solution and lignin-hemicellulose co-caused high efficiency separation of lignin and hemicellulose. This study integrated kinetic modeling and quantum chemical analysis to unravel the hydrogen-bond-mediated deconstruction mechanism, significantly advancing sustainable biorefinery strategies for efficient biomass valorization.