Prediction of liquid–liquid equilibria for PEG 2000–sodium citrate based aqueous two-phase systems

Liquid–liquid equilibrium (LLE) data were obtained for the polyethylene glycol 2000–sodium citrate–water system at 298.15, 308.15 and 318.15 K. Experimental and analytical methods were described in the previous article [T. Murugesan, M. Perumalsamy, J. Chem. Eng. Data 50 (2005) 1392]. The UNIQUAC, NRTL, UNIFAC and ASOG models have been used to fit the experimental LLE data. The interaction parameters of the models were estimated. The Debye–Huckel equation was used to calculate the long-range electrostatic interaction of the ions. The predicted LLE data by the models show good agreement with the experimental data.