Influence of the Salting-Out Ability and Temperature on the Liquid–Liquid Equilibria of Aqueous Two-Phase Systems Based on Ionic Liquid–Organic Salts–Water

In the present work, (liquid + liquid) equilibrium (LLE) data have been determined experimentally for aqueous two-phase systems formed by the ionic liquids n -butylpyridinium trifluoromethanesulfonate [Bpy]OTF and the organic salts of ammonium citrate ((NH 4 ) 3 C 6 H 5 O 7 ) and sodium succinate (Na 2 C 4 H 4 O 4 ) at T = (298.15, 318.15, and 328.15) K. Binodal curves were fitted to two empirical equations with different parameters. The quality of the experimental LLE data was established by applying the Othmer–Tobias and Bancroft correlations. The tie-line data of the systems at three different temperatures has also been described by the Setschenow-type equation. The phase diagrams for the two-phase systems show good agreement with the experimental data. Furthermore, the temperature dependence of the binodal curves has also been discussed. The results show the salting-out ability of Na 2 C 4 H 4 O 4 exceed (NH 4 ) 3 C 6 H 5 O 7, which can be related to the Gibbs energy.