Correlation of thermophysical properties of concentrated electrolyte solutions

A new model for the correlation of vapour pressure and heat of mixing data of aqueous and nonaqueous electrolyte solutions is presented. The model is based on association theory. Association of solvent and solvation of ions are described by chemical reaction chains, simplified by distribution functions. Applying thermodynamics of associated solutions as described by Prigogine and Defay (1962), expressions for vapour pressures and heats of mixing depending upon temperature and concentrations are derived. Results are shown for the correlation of vapour pressures and heat of mixing data of aqueous LiBr solutions in the temperature and concentration ranges 273–403 K and 0–25 molal.