Аннотация:An isothermal solubility method was used to obtain an isothermal cross section at 298.15 K for Cu(CH3SO3)2–CH3SO3H–H2O and Zn(CH3SO3)2–CH3SO3H–H2O systems. Up to 35 wt % of methanesulfonic acid (MSA), Cu(CH3SO3)2·4H2O is the only stable crystal hydrate in the first system. At 298.15 K, the solubility decreases from 39.1 wt % of Cu(CH3SO3)2 in pure water to 5.1 wt % of Cu(CH3SO3)2 in a solution of MSA with 39.0 wt % of CH3SO3H. In the other system, Zn(CH3SO3)2·12H2O is a stable form in solutions with less than 5.5 wt % of CH3SO3H. At a higher acid content, Zn(CH3SO3)2·4H2O precipitates, and it is a stable form in equilibrium with a liquid phase with up to 56.5 wt % of MSA. At this concentration, its solubility decreases to 5 wt %. Water vapor pressure was measured in the 288.15–308.15 K range to calculate water activity. The Pitzer–Simonson–Clegg model was used for liquid phase modeling. Ternary parameters were evaluated. As was shown, they are necessary for a correct solubility prediction, but the water vapor pressure is predicted with less difference without ternary parameters.
