Catalytic conversion of carbohydrates into 5-ethoxymethylfurfural using gamma-AlOOH and CeO2@B2O3 catalyst synergistic effect

Selective catalytic conversion of carbohydrates to 5-ethoxymethylfurfural (EMF) is a critical approach to the biorefinery. In this work, solid acid catalysts of gamma-AlOOH and CeO2@B2O3 were used to convert carbohydrates to EMF in a one-pot process, performed in an ethanol/DMSO solvent system. The synergistic effect of gamma-AlOOH and CeO2@B2O3 was studied. Furthermore, the morpho-structural properties of the catalysts were characterized, and the effects of reaction time, reaction temperature, catalyst load, and the amount of cosolvent on the conversion of glucose to EMF were examined and optimized. Under the reaction conditions of 170 degrees C for 20 h, glucose, sucrose, cellobiose, inulin and starch were used as raw materials, and the EMF yield range was 9.2-27.7%. The results showed that the synergistic effect of gamma-AlOOH and CeO2@B2O3 further causes the combination of multiple acid sites with different types and strength distributions. Particularly, the collaboration between weak, medium-strong, and strong acid, as well as between Lewis and Bronsted acidity, is of great significance for EMF generation. The reusability experiments showed that the combined catalytic system was easily separated and maintained catalytic activity for five successive reactions without further intermediate regeneration steps. This work provides a promising route for the catalytic conversion of biomass-derived carbohydrates into EMF.