One-pot conversion of carbohydrates into furan derivatives in biphasic tandem catalytic process

Biphasic tandem catalytic process (biTCP) is a generalized "one-pot" synthesis approach to produce hydrophobic biofuels or biobased chemicals from relatively hydrophilic biomass feedstocks. In this work, we report our findings on employing the biTCP to convert carbohydrates (such as fructose) to value-added furan derivative chemicals, 2,5-dimethyltetrahydrofuran (DMTHF), 2,5-dimethylfuran (DMF) or 5-methylfurfural (MF). Through the studies of kinetics and probe reactions, the reaction mechanism was explored, in which the key intermediates, such as 5-methylfurfural (MF) and DMF, were identified during the conversion of fructose to DMTHF. The catalytic effects of the different catalysts, H2SO4 and Pd/AC, partitioned in water and organic phases, respectively, were elucidated. The effect of various organic solvents and process conditions were systematically studied to maximize the production yield of DMTHF. At the optimum conditions, a similar to 70% yield of DMTHF was achieved from fructose with the hydrophobic Pd/AC and the hydrophilic Bronsted acid catalysts in the water-diethyl ether biphasic solution at 130 degrees C in 12 h. In addition, the effect of the co-solvent, dimethyl sulfoxide (DMSO), which modulated the distribution of furan products, was also investigated. Finally, the deactivation mechanism of the Pd/AC catalyst was discussed.