Kinetics of dimethylfurane production by dehydration and hydrogenolysis of carbohydrates

Abstract

To produce 2,5-dimethylfurane (DMF), an organic compound with fuel properties, carbohydrates were processed in a slurry reactor, by catalytic dehydration and hydrogenolysis. Fructose dehydration was evaluated with the conversion of fructose at a range of 423–463K and under a pressure of 34.5 and 51.7bar of argon in the presence of a γ-Al2O3 catalyst. The simultaneous dehydration/hydrogenolysis operation was also carried out with fructose in the presence of a Cu/γ-Al2O3 catalyst at 443K and under 34.5bar of hydrogen. Experimental data indicated that fructose via dehydration was transformed into 5-hydroximethylfurfural (HMF) and then, via hydrogenolysis into DMF. Model equations, including Langmuir–Hinshelwood’s kinetic laws were fitted to the experimental data, providing the quantification of the effects of the operating variables (temperature, pressure, copper wt.% in the catalyst). Dehydration of fructose into HMF via interaction with alumina was represented by the specific rate k1=3.28×10−2gL−1min−1, while the specific rate of hydrogenolysis of HMF into DMF on the copper sites was as k3=2.28×10−2gL−1min−1.