Solid-Liquid and Vapor-Liquid Equilibria Measurements for the Aqueous Ionic Liquid/Carbohydrate Systems

In order to study the soluting-effect of imidazolium-based ionic liquids (ILs) on sugar in aqueous systems, systematic experiments on the solid-liquid equilibria (SLE) and vapor-liquid equilibria (VLE) of ternary IL + sugar + water systems were carried out at different temperatures. The ILs 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim][HSO4]) and 1-butyl-3- methylimidazolium bromide ([Bmim][Br]) and carbohydrates including L-(+)-arabinose, D-(+)-xylose, D-(+)-glucose, D-(-)-fructose, maltose, sucrose, and maltitol were selected. The negative departures of the constant water activity lines from the semi-ideal behavior for [Bmim][Br]/sugar systems were somewhat smaller than [Bmim][HSO4]/sugar systems. The order of these departures was agreement with the obtained soluting-out coefficients, ks, from the solid-liquid equilibria experiments.