Production of 5‑Hydroxymethylfurfural from Glucose under Hydrothermal Conditions

5-Hydroxymethylfurfural (5-HMF) is an important biomass-based platform molecule with various commercial applications, and its green, efficient production is the key for value-added applications of lignocellulosic biomass. This work studied the preparation of 5-HMF from glucose using autogenic H⁺ and OH^- as the catalysts under hydrothermal conditions without additional catalysts. The effects of reaction temperature, time, pressure, and glucose concentration on the 5-HMF yield were discussed by single-factor experiments. The results show that the highest yield of 5-HMF is 70.2% and the selectivity is 80% at 180 °C for 6 h. The kinetics for glucose and fructose conversions was investigated in detail. It was found that the processes of glucose and fructose conversion to 5-HMF conform to the first-order reaction rate equation, showing the activation energies for 5-HMF formation of 94.5 and 89.6 kJ/mol, respectively. Moreover, 77% of the furfural yield could also be obtained by using xylose as the feedstock. This work offers an alternative, versatile, and eco-friendly strategy for furanic compound production from lignocellulosic biomass and sugar derivatives.