The Catalytic Conversion of d-Glucose to 5-Hydroxymethylfurfural in DMSO Using Metal Salts.

A wide range of metal halides and triflates were examined for the conversion of d-glucose to HMF in DMSO. Chromium and aluminium salts were identified as the most promising catalysts. The effect of process variables like initial d-glucose concentration (0.1-1.5 M), reaction time (5-360 min) and reaction temperature (100-140 °C) on the yield of HMF were examined at a fixed Al(OTf) concentration (50 mM). Highest yields of HMF (60 mol%) were obtained using 1 M d-glucose (16 wt%), Al(OTf) (5 mol%) at a temperature of 140 °C. A reaction pathway involving initial isomerisation of d-glucose to d-fructose followed by a number of dehydration steps is proposed. Kinetic analysis reveals that the reaction is second order in d-glucose with an activation energy of 138 kJ mol. [ABSTRACT FROM AUTHOR]