High-yield production of 5-hydroxymethylfurfural from d-fructose, d-glucose, and cellulose by its in situ removal from the reaction system

5-Hydroxymethylfurfural (5-HMF) from lignocellulosics has attracted attention as a platform chemical in chemical industry. In 5-HMF production processes, undesired degradation of 5-HMF by acid catalysts generally occurs, by which the 5-HMF yield is decreased along with formation of various types of by-products. In this study, we employed an acidic ionic liquid, 1-methylimidazolium hydrogen sulfate ([HMIM]HSO₄), as a reaction medium for 5-HMF production and carried out in situ removal of 5-HMF from the reaction solution by on-line vacuum steam distillation. In our reaction system, 76.1% 5-HMF yield was achieved from d-glucose, which yield was very similar to that from d-fructose (77.3%). Various types of cellulose samples also gave 5-HMF with the yield up to 68.3% regardless of their molecular weights and crystallinities. The 5-HMF produced was recovered as an aqueous solution with substantial purity and almost no contamination with the ionic liquid.