Аннотация:Novel solubility (SLE) and vapor–liquid phase equilibria data were obtained for ternary aqua systems containing calcium methanesulfonate and sodium (or magnesium) methanesulfonate. The isothermal solubility method was used to obtain an isothermal cross-section at 298.15 K for the Ca(CH3SO3)2–NaCH3SO3–H2O and the Ca(CH3SO3)2–Mg(CH3SO3)2–H2O systems. As expected, there are neither solid solutions nor double salts in both systems. The Mg(CH3SO3)2·12H2O hydrate is the only solid phase containing magnesium in the Ca(CH3SO3)2–Mg(CH3SO3)2–H2O system at 298.15 K. Water activity was determined at 298.15–323.15 K to expand the temperature range for NaCH3SO3–H2O by two methods (static vapor pressure measurement and hygrometer). Water vapor pressure was measured in the 288.15–308.15 K range in both ternary systems to calculate water activity. The Zdanovskii rule is applicable to both ternary systems in the composition range under investigation. The Pitzer–Simonson–Clegg model is used for liquid-phase modeling. Binary parameters for NaCH3SO3–H2O were evaluated for the first time, as well as the solubility constant for NaCH3SO3, in the 250–323 K temperature range. Ternary parameters of the PSC model were evaluated for the first time, too, needed for a correct solubility prediction. The water activity was predicted with a higher accuracy without ternary parameters.
