Conversion of Glucose to 5-Hydroxymethylfurfural (5-HMF) Over Sulfated Zinc Oxide Catalyst

Abstract

Zinc oxide and sulfated zinc oxide catalysts prepared by precipitation and wetness impregnation methods, respectively, and characterized by various sophisticated techniques like XRD, FE-SEM, EDX, TGA, NH3-TPD and N2 adsorption-desorption. These catalysts tested for glucose dehydration to 5-hydroxymethylfurfural (5-HMF) formation and the influence of several reaction constraints as reaction temperature, reaction time, catalyst amount, and sulfation loading on ZnO were evaluated in terms of glucose conversion and 5-HMF Yield. Catalytic activity results demonstrated a maximum of 15.8 % 5-HMF yield with complete conversion of glucose over 2.5M SO42-/ZnO catalyst at 220°C after a reaction time of 6 h in the presence of dimethyl sulfoxide (DMSO) reaction solvent. The formation of other unidentified side reaction products restricted the higher yield of HMF. Reaction parameter study suggested that higher reaction temperature (> 220oC), higher substrate to catalyst ratio (> 0.5) was not beneficial for higher yield of HMF. Longer reaction time has not affected the yield of HMF. The results obtained also suggested that the acidic nature of catalyst was responsible for the high conversion of glucose.