Journal of Chemical and Engineering Data, Vol.65, No.5, 2790-2797, 2020
Activity Coefficients of Water at Infinite Dilution in Common Oxygenated Solvents
Activity coefficients of water at infinite dilution in 12 common oxygenated solvents (namely methanol, ethanol, propan-l-ol, propan-2-ol, 2-methylpropan-2-ol, propan-2-one, tetrahydrofuran, 1,3-dioxolane, dimethoxymethane, 1,2-dimethoxyethane, ethyl methanoate, and methyl ethanoate) were measured at several temperatures using the technique of comparative ebulliometry. A comprehensive critical review of such literature data as well as data on relevant thermal properties (enthalpies and heat capacities of water dissolution) was further carried out disclosing however total lack of this information for the five latter solvents having two oxygen atoms in their molecule. For each solvent, all available data were correlated with a suitable model equation providing adequate simultaneous descriptions of the information. As a result, the recommended temperature dependence for the activity coefficient of water as well as the respective values of infinite dilution thermodynamic functions of water in the examined solvents at 298.15 K were established. In all solvents, the infinite dilution activity coefficient of water at 298.15 K is greater than unity, increasing consistently as the relative permittivity of the solvent decreases. The variation of infinite dilution thermodynamic functions was found to be considerably interlinked by enthalpy/entropy compensation (r(2) = 0.9383). Furthermore, the performance of the Modified UNIFAC, COSMO-SAC, and MOSCED approaches to predict the activity coefficients of water in the studied solvents was examined. The predictions are quite unsatisfactory, except for those by the Modified UNIFAC for the solvents with one oxygen atom in their molecule.