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چکیده
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In this study, in order to obtain a relation between the liquid – liquid equilibria (LLE) and vapor – liquid equilibria (VLE) behavior of aqueous carbohydrate-ionic liquid solutions, isopiestic and binodal measurements were carried out for different carbohydrate + 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) + water systems. In the VLE section, the water activity, isopiestic equilibrium molalities (constant water activity lines), osmotic coefficient, vapor pressure depression data were obtained for binary and ternary aqueous systems of [Bmim][BF4] in the absence and presence of seven carbohydrates including monosaccharides (L-(+)-arabinose, D-(+)-xylose, D-(+)-glucose and D-(-)-fructose), disaccharides (maltose and sucrose), and one polyol (maltitol) at T = 298.15, 303.15, and 308.15 K. In the LLE section, the binodal curves were obtained for the investigated systems at different temperatures. It was found that, by increasing temperature and the number of hydroxyl groups on the sugar molecules the binodal curves shifted to the higher and the lower concentrations of solutes, respectively. The constant water activity lines in mono- and biphasic regions of all the ternary [Bmim][BF4] + carbohydrate + water systems show a large negative deviation from the Zdanovskii−Stokes−Robinson (ZSR) [3] rule and these deviations in the monophasic region are larger than those in the biphasic region.
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