Chemoselective Hydrogenation of Biomass-Derived 5-Hydroxymethylfurfural into the Liquid Biofuel 2,5-Dimethylfuran

In recent years, 2,5-dimethylfuran (DMF), which is produced by the selective hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) and is considered as a new-fashioned liquid biofuel for transportation, has received much more attention from many researchers in the world. Compared to the current market-leading bioethanol, DMF possesses a higher energy density, a higher boiling point, and a higher octane number and is immiscible with water. At present, the study on the selective hydrogenation of HMF into DMF is still in its infancy; however, it has been becoming a very important research orientation in the field of bioenergy. In consideration of the excellent physicochemical properties, the momentous application values, and the broad market prospects of DMF, the reported catalytic systems and the latest research achievements for the selective hydrogenation of HMF into DMF in light of the diversity of hydrogen donors such as molecular hydrogen, formic acid, alcohols, and water are systematically summarized and discussed, and the reaction mechanism of DMF synthesis and the combustion performance and safety of DMF are also outlined in this critical review. Moreover, some potential research trends in future studies are prospected to offer the valuable ideas and advice for the selective hydrogenation of HMF and provide the theoretical references and technical support for the practical production and application of DMF.