Kinetics of furfural production by dehydration of xylose in a biphasic reactor with microwave heating

Abstract

In this paper we report a kinetic model for the dehydration of xylose to furfural in a biphasic batch reactor with microwave heating. There are four key steps in our kinetic model: (1) xylose dehydration to form furfural; (2) furfural reaction to form degradation products; (3) furfural reaction with xylose to form degradation products, and (4) mass transfer of furfural from the aqueous phase into the organic phase (methyl isobutyl ketone - MIBK). This kinetic model was used to fit experimental data collected in this study. The apparent activation energy for xylose dehydration is higher than the apparent activation energy for the degradation reactions. The biphasic system does not alter the fundamental kinetics in the aqueous phase. The organic layer, which serves as “storage” for the extracted furfural, is crucial to maximize product yield. Microwave heating does not change the kinetics compared to heating by conventional means. We use our model to describe the optimal reaction conditions for furfural production. These conditions occur in a biphasic regime at higher temperatures (i.e. 170 °C) and short reaction times. We estimate that at these conditions furfural yields in a biphasic system can reach 85%. At these same conditions in a monophase system furfural yields are only 30%.