Liquid-Liquid Equilibrium Data for the Ionic Liquid N-Ethyl-Pyridinium Bromide with Several Sodium Salts and Potassium Salts

Abstract

The liquid-liquid equilibrium (LLE) data for systems containing N-ethyl-pyridinium bromide ([EPy]Br), salt (Na2HPO4, K2HPO4, K2SO4, C4O6H4KNa), and water have been measured experimentally at T=298.15 K and the formations of these four aqueous two-phase systems (ATPSs) have been discussed. Also, the effective excluded volume (EEV) values obtained from the binodal models for the four systems were determined and the salting-out abilities of different salts follow the order of K2SO4>K2HPO4>Na2HPO4>C4O6H4KNa. The solubility data were correlated by the Merchuk and other equations while the tie-line data by the Othmer-Tobias, Bancroft, two-parameter, and Setschenow-type equations. The correlation coefficients evidenced that experimental data fitted well to all these equations. These four salts were proved successfully to form ATPSs with N-ethyl-pyridinium bromide, making a significant contribution to the further study of this kind of ATPS.