Acid-Catalyzed Dehydration of Fructose and Inulin with Glycerol or Glycerol Carbonate as Renewably Sourced Co-Solvent

Ionic liquids (ILs) can be partially substituted by glycerol or glycerol carbonate as cheap, safe, and renewably sourced co‐solvents in the acid‐catalyzed dehydration of fructose and inulin to 5‐hydroxymethylfurfural (HMF). In the particular case of glycerol, we found that HMF can be conveniently extracted from the IL/glycerol (65:35) mixture with methylisobutylketone, limiting the reactivity of glycerol with HMF and allowing the recovery of HMF with a high purity (95 %). Influences of the fructose content, temperature, and the nature of the ionic liquid are also discussed. The possible use of industrial‐grade glycerin is also investigated. We demonstrate that by using glycerol carbonate, up to 90 wt % of the IL can be successfully substituted, decreasing the environmental costs of traditional IL‐based processes. Super subs: The amount of the ionic liquid [BMIM]Cl required for the acid‐catalyzed dehydration of fructose and inulin into HMF, over Amberlyst 70 resin as solid acid catalyst, can be reduced by substituting it (up to 90 wt %) with large amounts of glycerol or glycerol carbonate; cheap co‐solvents from renewable sources.