Catalytic conversion of cellulose into 5-hydroxymethylfurfural in high yields via a two-step process

As a key renewable chemical for plastics and fine chemicals, the preparation of 5-hydroxymethylfurfural (5-HMF) from biomass is an important research topic. Cellulose, although abundant in nature, is difficult to convert to 5-HMF in good yields due to its recalcitrant and heterogeneous nature. In this work, we show an efficient two-step process for converting microcrystalline cellulose into 5-HMF with ionic liquids under mild conditions. In the first step, high glucose yields of above 80% could be obtained from the cellulose hydrolysis by a strong acidic cation exchange resin in 1-ethyl-3-methyl imidazolium chloride ([EMIM][Cl]) with gradual addition of water. In the second step, the resin was separated from the reaction mixture and CrCl₃ was added which lead to a 5-HMF yield of 73% based on cellulose substrate. The strategy can allow practical conversion of biomass into bio-derived products.