Dehydration of fructose to 5-hydroxymethylfurfural (HMF) in an aqueous acetonitrile biphasic system in the presence of acidic ionic liquids

In this study, we report that phase separation of water/acetonitrile solution to a biphasic system can be induced by the presence of an acidic ionic liquid, i.e., 1-methyl-3-(butyl-4-chlorosulfonyl) imidazolium chlorosulfate ([MBCIm]SO3Cl), which allows to produce pseudo ternary phase of the/water/actonitrile/[MBCIm]SO3Cl system at room temperature. Based on this finding, an efficient and recyclable aqueous acetonitrile biphasic system is established for catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) in the presence of [MBCIm]SO3Cl at low temperature in a shorter period of time. The ionic liquids remaining in the organic phase can be efficiently removed by simple treatment with alumina. This leaves only HMF, with a yield of up to 88.7%, in the acetonitrile phase, which could be easily removable.

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► A novel method is established to induce phase separation of water/acetonitrile by using an acidic ionic liquid.
► We report a novel and recyclable aqueous biphasic system for dehydration of fructose to HMF.
► The current system can afford a yield of HMF in organic phase as high as 88.7% at low reaction temperature.
► The potential of the current system is investigated by a 50-times-scale-up experiment.