Recent advances in catalytic and autocatalytic production of biomass-derived 5-hydroxymethylfurfural

As a typical biomass-derived platform compound, 5-hydroxymethylfurfural (HMF) can be used to synthesize numerous high-quality fuels and high-value chemicals, so it has captured great attention and research interest in recent years. HMF shows excellent application potential and market prospect, but its practical production has not yet been implemented, in which one of the most major bottlenecks should be the lower conversion efficiency of catalytic systems. Therefore, to solve this issue as soon as possible, considerable efforts have been devoted to explore the novel and effective catalytic systems over the past two decades. For a better understanding of current research situation, this review not only systematically summarizes the recent progresses on various homogeneous catalysts (such as organic acids, mineral acids, metal chlorides, metal triflates and ionic liquids), but also comprehensively generalizes the latest achievements on various heterogeneous catalysts (such as acidic resins, acidic zeolites, metal oxides, acidulated metal oxides, metal phosphates, heteropolyacid salts, functionalized silicas, functionalized clays, coordination polymers, carbonaceous acids and magnetic materials) for the conversion of biomass-derived carbohydrates and natural biomass resources into HMF, in which the roles and synergistic effects of different active sites of catalysts in hydrolysis, isomerization and dehydration reactions are emphatically discussed. Moreover, this review particularly outlines and analyzes the catalyst-free systems and autocatalytic mechanisms for the production of HMF, and proposes a few potential research trends in future studies. All in all, this review can provide some valuable enlightenments and feasible ideas for developing high-efficiency catalytic systems and promoting the practical production of HMF.