A new outlook on solubility of carbohydrates and sugar alcohols in ionic liquids

Abstract

Ionic liquids are innovative media characterised by an easy tunability of physical and chemical properties with the potential for broad usefulness in a wide spectrum of chemical applications. One example of such an application is a complex biorefinery concept leading to the exploitation of the biomass for the production of energy (heat, power, fuel) and value added products. Until now ionic liquids have proven their feasibility to dissolve selectively biomass as a whole as well as individual carbohydrates. This work demonstrates the solubility of carbohydrates and value added products—sugar alcohols—which can be obtained from biomass through the biorefinery concept. The novelty of our investigation includes either solubility studies of sugar alcohols or an involvement of unexplored ionic liquids yet. In this research, a variety of ionic liquids constituted by imidazolium, pyridinium and phosphonium cations was applied. Furthermore, anions of ionic liquids, attractive from a point of view of a broad application, such as: 2-(2-methoxyethoxy)ethylsulfate, hydrogen sulfate, thiocyanate, tricyanomethanide, tetrachloroferrate, perfluorobutane sulfonate and tosylate were investigated. In this work, it was discovered that solubility of carbohydrates and sugar alcohols can exceed even 75 wt% at an easily achievable temperature depending on the choice of the ionic liquid.