Gram-Scale Synthesis of 5-Hydroxymethylfurfural from Fructose Using Cerium Triflate and Choline Chloride at Atmospheric Pressure.

The selective conversion of renewable sugars into 5-hydroxymethylfurfural (HMF) remains a major challenge in green chemistry due to side reactions and product instability. A simple and scalable protocol is reported for the gram-scale production of HMF from D-fructose under atmospheric pressure. The system combines cerium(III) triflate, a cost-effective and water-tolerant Lewis acid, with choline chloride, which stabilizes HMF and the intermediates during synthesis. Conducted in a biphasic setup using methyl propyl ketone as extraction solvent, the method affords up to 86% isolated yield within 2 h at 130 °C, while suppressing side-product formation. The catalytic phase can be recycled for at least five cycles with yields above 70%. Compared to previous protocols, this method reduces both E-factor and process mass intensity (PMI) by ≈80%, while scaling from milligram to gram quantities without loss of selectivity. The operational simplicity, high efficiency, and improved green metrics highlight the potential of this system for sustainable biomass valorization.