Low dosage ionic liquid-driven mild and selective lignocellulosic deconstruction of corn stover using biphasic co-solvent systems.

Ionic liquids (ILs) are highly effective in lignocellulose pretreatment due to their excellent solvation properties. However, the single-phase nature of conventional IL pretreatment not only causes component mixing, complicating separation and utilization, but also limits large-scale application due to the high cost. To address these challenges, this study developed a biphasic pretreatment system combining the protic IL [BHEM]mesy with aqueous pentanol, aiming to efficiently fractionate corn stover under mild conditions. The effects of varying conditions on corn stover composition were systematically investigated. The optimal pretreatment conditions (10 % IL, 60 % pentanol, 140 °C, 60 min) resulted in 91.6 % cellulose content in solid residue with 89.3 % hemicellulose and 82.9 % lignin removal. Enzymatic hydrolysis of pretreated residues was significantly better than residues pretreated with IL or pentanol alone. In the biphasic system, 70.8 % of the available xylose dissolved into the aqueous phase, while the organic phase facilitated the recovery of 82.9 % lignin with high phenolic hydroxyl. Quantum chemical calculations revealed that the IL-pentanol co-solvent system reduces IL consumption while exhibiting higher reactivity than either component alone. This study demonstrates a cost-effective and efficient approach for lignocellulose pretreatment, offering significant potential for high-value utilization of its components.