Measurement and correlation of phase equilibria for several PVP + salt aqueous two-phase systems at 303.15 K

Phase diagrams and liquid–liquid equilibrium (LLE) data of the aqueous polyvinylpyrrolidone (PVP) + sodium sulfate, PVP + sodium carbonate and PVP + sodium succinate systems have been determined experimentally at 303.15 K. The effect of the type of salt on the binodal and tie-lines has been studied. The salting-out power of salts in these systems was determined and this power can be arranged with respect to the anions as CO32− > SO42− > C4H4O42−. Furthermore, the extended local composition models NRTL and Wilson have been used to correlate the phase behavior of these systems. Good agreement was obtained with the experimental data with both models, especially with the extended Wilson model.