The dehydration of fructose to 5-hydroxymethylfurfural (5-HMF) with room temperature ionic liquids (ILs) is a way of producing liquid fuels from renewable resources, but separation of products and IL is energy intensive. In this work, a heteropolyacid salt of an IL-forming cation functionalized with a propanesulfonate group, 1-(3-sulfonicacid)propyl-3-methyl imidazolium phosphotungstate ([MIM-PS](3)PW12O40), was used as a catalyst rather than as a solvent in the conversion of fructose to 5-HMF. The maximum yield of 5-HMF was 99.1% at 120 degrees C after 2 h using sec-butanol as solvent, and the catalyst was separated from the reaction mixture by a simple process at the end of the reaction and reused six times without loss of activity. (C) 2011 Elsevier Ltd. All rights reserved.