Efficient conversion of glucose into 5-HMF catalyzed by lignin-derived mesoporous carbon solid acid in a biphasic system

A lignin-derived mesoporous carbon solid acid (LDMCS) catalyst was prepared by high temperature carbonization and subsequent sulfonation treatment using alkali lignin as the carbon source and KCl as a salt template. The prepared LDMCS has an irregular mesoporous structure with a narrow pore size distribution (concentrated at 4 nm), large specific surface area (1123.0 m2 g−1) and high -SO3H group density (2.20 mmol g−1). Compared with other types of solid acids reported in the literature, the prepared LDMCS catalyst has equivalent or better catalytic performance in the catalytic conversion of glucose to 5-hydroxymethylfurfural (5-HMF). A glucose conversion of 97.7% and a 5-HMF yield of 57.8% were obtained with the aqNaCl-THF (1:3) biphasic solvent system under the optimized reaction conditions with reaction temperature of 160 °C, reaction time of 2.5 h, and catalyst loading of 1 mg mg−1. More importantly, the 5-HMF yield still reached 40.9% after 5 cycles of the catalyst use, indicating that there was no significant loss of catalytic activity.