Enhancements in the production of 5-HMF from glucose: A review on recent advances in heterogeneous catalysts and solvent effects

The HMF or 5-hydroxymethylfurural is a crucial platform chemical classified as a "drop-in biofuel." HMF synthesis procedures have experienced notable advancements in recent years, including the shift from homogeneous to heterogeneous catalysts, the substitution of aqueous solutions with organic phases, and the adoption of biphasic systems to mitigate limitations caused by side reactions, among other innovations. Nonetheless, achieving a balance among selectivity, cost, energy consumption, and environmental impact in the production of HMF from economical glucose-derived substrates presents a formidable challenge. Various strategies have been developed over the past decade to address these issues. This review provides a current overview of recent advancements in solvent types and heterogeneous catalysts, including zeolites, metal oxides, carbonaceous and silica-based materials, heteropolyacids, and polymer-based systems. In addition, the reaction mechanisms of established solid catalysts employed to enhance HMF production are detailed.