Prediction of Solid-Liquid Equilibrium for KCl in Mixed Water-Ethanol Solutions Using the LIQUAC Model

Introduction The solubilities of nearly insoluble salts in water can be calculated directly using their solubility product constants, since at low ion concentrations the required activity coefficients are very close to unity. At higher concentrations, the mean activity coefficients of the ions have to be taken into account. In 1994, Li et al.[1,2] developed the LIQUAC model for systems with strong electrolytes based on results from statistical thermodynamics taking into account the interact…     

Prediction of Solid-Liquid Equilibrium for KCI in Mixed Water-Ethanol Solutions Using the LIQUAC Model

The LIQUAC model is often used to predict vapor-liquid equilibria, osmotic coefficients, and mean ion activity coefficients for electrolyte systems. This paper describes a thermodynamic method to analyze solid-liquid equilibrium for electrolytes in mixed solvents solutions using the LIQUAC model. The KCI solubilities in mixed water-ethanol solutions are predicted with the LIQUAC model and its original interaction parameters. This method is also used to obtain new K^＋-ethanol interaction parameters in the LIQUAC model from the solubility data. The new interaction parameters accurately predict the vapor-liquid equilibrium data of K^＋ salts （including KCI, KBr, and KCOOCH3） in mixed water-ethanol solutions. The results illustrate the flexibility of the LIQUAC model which can predict not only vapor-liquid equilibrium but also solid-liquid equilibrium in mixed solvent systems.