Strategies on utilizing biomass derived 5-hydroxymethylfufural by catalytic reactions: Pathways and mechanisms

Biomass refinery, produces chemicals that can replace pristine petroleum-derived chemicals through chemical/biological engineering processes, and is regarded as a renewable energy source for achieving environmental-friendly production and sustainability. Among various kinds of biomass derived chemicals, 5-hydroxymethylfufural (5-HMF), produced by the dehydration of fructose via glucose isomerization, has remarkable potential as a platform chemical for utilization in value-added products such as pharmaceutical, bio plastics, bio fuels and polyesters. Representative chemicals produced from 5-HMF are 2,5-diformylfuran and 2,5-furandicarboxylic acid, which are generated via oxidation reactions, and 2,5-bis(hydroxymethyl)furan which are generated via a reduction reaction. Theses oxidation/reduction products can potentially be used as value-added chemicals for polymer vitrimers, and in bioplastic monomers for replacing pristine polyethylene terephthalate, polyurethane and polyesters. Herein, the recent achievements in the catalytic conversion of 5-HMF to oxidation/reduction products using heterogeneous catalysts and electrocatalysts are presented, including the detailed catalytic mechanisms of 5-HMF valorization. The current challenges and future perspectives are discussed to prompt further studies and catalyst design for the oxidation/reduction of 5-HMF to useful chemicals.