Task-Specific Organic Salts and Ionic Liquids Binary Mixtures: A Combination to Obtain 5-Hydroxymethylfurfural From Carbohydrates

What is it about?

We studied the conversion of the carbohydrates fructose and sucrose into 5-HMF using sulfonic acid functionalized imidazolium and diimidazolium salts as catalysts, and the ionic liquid mixture [bmim]2[Cl][BF4] as solvent. We also investigated the effect of the different structure of the catalysts, finding that the relative position of the reactive moieties in the dicationic salts plays a role, and that the acid strength of these salt is not the only factor determining the observed reactivity. The protocol employed by us also showed good reciclability of the solvent.

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Why is it important?

In this work we obtained very good yields of 5-HMF from carbohydrates, at the relatively low temperatures of 60 °C and 80 °C for fructose and sucrose, respectively. We also elucidated the structural features of the catalyst that affects the reactivity observed, and finally provided mechanistic insight by 1H NMR in situ monitoring of the reaction.