Effect of potassium citrate salts on the vapor-liquid equilibrium properties of aqueous solutions of alanine at different temperatures

Water activity measurements by isopiestic method have been carried out on the aqueous solutions of alanine + potassium di-hydrogen citrate (KH₂Cit) and alanine + tri-potassium citrate (K₃Cit) over a range of temperatures at atmospheric pressure. From these measurements, values of the vapor pressure of solutions were determined. The effect of temperature and charge on the anion of salts on the vapor–liquid equilibrium of the investigated systems has been studied. The experimental water activities have been correlated successfully with the segment-based local composition Wilson and NRTL models. The agreement between the correlations and the experimental data is good.