Ionic liquid with metal complexes: An efficient catalyst for selective dehydration of fructose to 5-hydroxymethylfurfural

The dehydration of D-fructose has been studied with different kinds of pyridinium based dicationic ionic liquids as catalyst. The results showed that 1,1'-hexane-1,6-diylbis (3-methylpyridinium) tetrachloronickelate (II) [C-6(Mpy)(2)][NiCl4](2-) in DMSO and 1,1'-decane-1,10-diylbis (3-ethylpyridinium) dibromide [C-10(Epy)(2)]2Br(-) without DMSO have high catalytic activity. Highly efficient and selective dehydration of D-fructose to 5-hydroxymethylfurfural (HMF) was achieved in dimethyl sulfoxide (DMSO) under mild conditions with a fructose conversion of 95.6% and 95.5% HMF yield was achieved in 60 min reaction time at 110 degrees C and 87.1% yield obtained from [C-10(Epy)(2)]2Br(-) without DMSO at 100 degrees C in 90 min reaction time. The ionic liquids used in this study will benefit many biofuel-related applications. (C) 2013 Elsevier B.V. All rights reserved.