Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Precise vapor pressure osmometry (VPO) measurements at 308.15 K were conducted for solutions of three ILs 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]), 1-butyl-3-methylimidazolium bromide ([Bmim][Br]), and 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim][HSO4]) in aqueous solutions of three carbohydrates sucrose, maltose and maltitol as well as for solutions of the carbohydrates in aqueous solutions of these ILs. Because of the unfavorable IL-carbohydrate interactions, all the investigated IL + carbohydrates aqueous systems show the soluting-out effect and vapor-liquid equilibria behavior of these systems in mono-phasic region show the negative deviation from the semi-ideal behavior (aw + 1 less than adeg wIL + adeg wC and Ap less than Apdeg IL + Apdeg C). For a certain carbohydrate and at the same molality of IL, the magnitude of the departures for the investigated ILs follows the order: [Bmim][BF4] greater than [Bmim][HSO4] greater thangreater than [Bmim][Br]. In the case of [Bmim][BF4]/carbohydrate aqueous systems which has a phase separation capability, the soluting-out power of the carbohydrates on [Bmim][BF4] in aqueous solutions (or negative deviation from the semi-ideal behavior) reduced by decreasing the hydrophilicity of the carbohydrates. Aqueous [Bmim][Br]/carbohydrate and [Bmim][HSO4]/carbohydrate systems are unable to form the ABS and the soluting-out effect of the ILs on the aqueous carbohydrate solutions is appeared in the form of precipitation of sugars from the aqueous solutions.