Liquid-Liquid Equilibria of Ionic Liquid 1-Butyl-3-Methylimidazolium Tetrafluoroborate plus Sodium and Ammonium Citrate Aqueous Two-Phase Systems at (298.15, 308.15, and 323.15) K

Binodal curves of the aqueous 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) + sodium citrate (Na3C6H5O7) and [Bmim]BF4 + ammonium tartrate ((NH4)(3)C6H5O7) systems have been determined experimentally at T = (298.15, 308.15, and 323.15) K. The Merchuk equation was used to correlate the binodal data. The effective excluded volume (EEV) values obtained from the binodal model for these two systems were determined. The binodal curves and EEV both indicate that the salting-out abilities of the two salts follow the order: Na3C6H5O7 > (NH4)(3)C6H5O7. It was demonstrated that the two-phase area was expanded with a decrease in temperature, while the slope of the tie lines slightly decreases with an increase in temperature. The liquid liquid equilibrium (LLE) data were obtained by density determination and binodal curves correlation of these systems. The Othmer-Tobias and Bancroft and two-parameter equations were used for the correlation of the tie-line data. Good agreement was obtained with the experimental tie-line data with both models.