Sulfonated lignin-derived ordered mesoporous carbon with highly selective and recyclable catalysis for the conversion of fructose into 5-hydroxymethylfurfural

Sulfonic acid-functionalized lignin-derived mesoporous carbon (LDM C-S O3H) was prepared using phenolation and evaporation induced self-assembly method followed by sulfonation. The obtained LDM C-S O3H bearing sulfonic acid density of 0.6528 mmol/g possessed a well-ordered two-dimensional hexagonal mesoporous characteristics. A 5-hydroxymethylfurfural (5-HMF) yield of 98.0% with a full fructose conversion was obtained using LDM C-S O3H as catalyst at 140 degrees C for 2 h in DMSO. Reactive kinetics studies revealed that fructose conversion in DMSO without catalyst or catalyzed by LDMC-SO3H may obey pseudo-first-order kinetics, and the activation energy of latter (72 kJ/mol) was much lower than that of former (114 kJ/mol). Adsorption kinetics studies indicated that almost no 5-HMF adsorbed onto LDM C-S O3H probably had a great contribution to the high selectivity of up to 98.0%, while the fructose adsorption on LDM C-S O3H was a diffusion-controlling adsorption process with more following Bangham kinetic model and Weber-Morris kinetic model owing to the characteristics of ordered mesostructure of LDM C-S O3H. Moreover, LDM C-S O3H exhibited superior reusability and stability in catalytic performance with a 5-HMF yield higher than 88.0% in six runs probably due to the synergistic effect of mesopore structure with a special surface and -SO3H groups with a relatively high content. These research results will contribute to a better understanding of structure-performance relationship of LDM C-S O3H used as an efficient catalyst in the fructose-to-5-HMF transformation as well as the high-value utilization of lignin in the field of catalysis.