Efficient dehydration of fructose into 5-HMF using a weakly-acidic catalyst prepared from a lignin-derived mesoporous carbon

A lignin-derived mesoporous carbon solid acid catalyst (LDMCC) was prepared using alkali lignin as a carbon source and KCl as a salt template to generate a carbon support that was carboxylated with acrylic acid. The prepared LDMCCs were characterized by various spectroscopies (FTIR, XPS, XRD, Raman), porosity determinations (BET), microscopies (SEM, TEM), thermogravimetric analysis, and acid-base titration. The LDMCC produced at the highest carbonization temperature (900 °C) possesses a rich porous structure, high specific surface area (1197.1 m2·g−1), large pore volume (0.63 cm3·g−1), and abundant –COOH groups (2.4 mmol·g−1). This weakly acidic catalyst exhibits excellent synergistic catalytic performance with DMSO in the catalytic dehydration of fructose to prepare 5-hydroxymethylfurfural (5-HMF); the yield of 5-HMF was 96.0% using dimethyl sulfoxide as the solvent, reaction conditions of 180 °C for 2.0 h, and a catalyst loading of 0.1 mg·mg−1. In addition, the prepared LDMCC exhibits excellent reusability over five cycles of use without significant loss in its catalytic activity. This study provides a novel green route for the preparation of a weakly acidic catalyst which may be useful for a variety of biomass conversion processes.