Liquid-liquid equilibria of ionic liquid 1-butyl-pyridinium tetrafluoroborate and ammonium citrate/trisodium citrate/sodium succinate/sodium acetate aqueous two-phase systems at 303.15Â K: Experiment and correlation

Liquid-liquid equilibrium data have been determined for 1-butyl-pyridinium tetrafluoroborate([Bpy]BF4) + ammonium citrate ((NH4)3C6H5O7)/trisodium citrate (Na3C6H5O7)/sodium succinate (Na2C4H4O4)/sodium acetate(CH3COONa) aqueous two-phase systems at T = 303.15 K, respectively. The effective excluded volume (EEV) values obtained from the binodal model for these four systems were determined, which indicates that the salting-out abilities of the four salts follow the order: Na3C6H5O7 > (NH4)3C6H5O7, Na3C6H5O7 > Na2C4H4O4 > CH3COONa. Then the binodal data were modeled by Merchuk and another two parameter equations. The Othmer-Tobias, Bancroft, two-parameter and Setschenow-type equations were used for the correlation of the tie-line data. Both the correlations of binodal data and tie-line data show good agreement for the investigated systems.