Solubilities of Sodium Chloride and Potassium Chloride in Water + Ethanol Mixtures from (298 to 323) K

The solubilities of sodium chloride in water + ethanol mixtures and of sodium and potassium chlorides in systems of NaCl + KCl + water + ethanol were determined from (298 to 323) K and up to 20 mass % alcohol in the solvent. An empirical fit of the measured data enabled the calculation of the solubility of NaCl in water + ethanol mixtures as a function of temperature and alcohol content with an average deviation of 0.1 mass %. Solubility data in the quaternary systems were correlated using an algorithm that makes use of the Pitzer mole fraction-based equations for the activity coefficients of the electrolytes. The parameters for the activity coefficient equations, taken from the literature, allowed fair agreement between calculated and experimental solubilities in the NaCl field. However, in the KCl domain the deviations were somewhat biased. A better fit of the entire set of solubilities was obtained by revising the value of the short-range interaction parameter Qethanol,NaCl,KCl. After this tuning, the algorithm reproduces the experimental solubility data of both salts with a standard deviation of ±0.023 mol·kgsolvent-1. The maximum differences between the experimental and calculated contents of sodium and potassium chlorides in the invariant composition mixtures are 1.2% and 3.5%, respectively.