Phase-switchable catalytic system design for the efficient and economical conversion of fructose to 5-hydroxymethylfurfural

Abstract

5-Hydroxymethylfurfural (HMF) is a central platform molecule linking plant biomass to renewable fuels and chemicals, yet its scalable production hindered by instability and costly separation. Here we present a temperature-responsive, phase-switchable acetone/betaine hydrochloride (BHC) aqueous system that unifies catalysis, product stabilization, and catalyst/solvent recycling in one platform. The system behaves as a liquid-liquid biphasic medium during fructose dehydration, enabling in situ extraction of HMF into acetone, and switches to a solid-liquid state upon cooling, allowing quantitative BHC recovery. Molecular simulations reveal that BHC accelerates dehydration via directional hydrogen bonding, while acetone selectively solvates HMF to suppress degradation. The system achieves up to 86.7% HMF yield at a high concentration of 30 wt% fructose, sustains >75% yield at 60 wt%, and remains robust over multiple cycles. A 1000-fold scaleup validates kilogram-scale production, and techno-economic analysis projects cost competitiveness with all reported routes. This phase-switchable concept establishes a broadly applicable catalytic strategy for catalyst/solvent recovery and product stabilization in biomass valorization.