The weak interaction between polar aprotic solvent and saline water enables efficient production of furans from lignocellulosic biomass

Abstract

Herein, based on the studies on intermolecular weak interactions, we propose a novel perspective on the design of a biphasic system from a polar aprotic solvent (PAS) and saline water, which plays a vital role in the efficient production of furans from a lignocellulosic biomass. Interestingly, molecular dynamics simulation reveals the formation mechanism of the biphasic system from the original miscible PAS and water. The stronger interaction of Na⁺ and Cl⁻ with water is proven to be responsible for the dissociation of water from water-miscible γ-valerolactone (GVL) to form the biphasic system. Similarly, the outstanding effect on the extraction and stabilization of furfural (FAL) could also be attributed to the better interaction of PAS with FAL. As a result, a remarkable FAL yield of 80.5 mol% could be obtained in the biphasic system of GVL/NaCl aqueous solution (aq.) with 0.3 mmol AlCl₃ at 150 °C for 1 h. Moreover, the synergistic catalytic effect between NaCl and AlCl₃ was confirmed by blank experiments and in situ²³Na NMR spectroscopy. Besides, this process enables the GVL/NaCl aq. biphasic system and AlCl₃ catalyst to exhibit excellent recovery with no significant FAL loss after three times of recycling. This work provides a feasible strategy for efficient biorefinery in biphasic systems.