Efficient extraction of 5-hydroxymethylfurfural from multicomponents aqueous solution by hydrophobic deep eutectic solvents

This study investigates the extraction of 5-hydroxymethylfurfural (5-HMF) from multicomponent aqueous solutions using hydrophobic deep eutectic solvents (DESs) based on terpenoids. The optimized octanoic acidthymol (1:1) DES achieved an extraction efficiency of 69.92 % with selectivity coefficients of alpha 5-HMF/LA = 9.05 and alpha 5-HMF/FA = 232.39. Moreover, after four stages of extraction, the efficiency of 5-HMF extraction reached 98.54 %, with alpha 5-HMF/LA and alpha 5-HMF/FA values of 28.51 and 1698.13, respectively, demonstrating superior separation of 5-HMF from levulinic acid (LA) and formic acid (FA). Compared to existing technologies, this method offers higher extraction efficiency and selectivity with lower toxicity and operational costs. Theoretical calculations confirmed the role of thymol as both a hydrogen bond donor and acceptor, enhancing non-covalent interactions with 5-HMF. Kinetic studies revealed that lower temperatures favor DES extraction performance, offering new insights into the industrial application of hydrophobic DESs for bio-based chemical separations.