Liquid−Liquid Equilibria of Aqueous Two-Phase Systems Containing 1-Butyl-3-methylimidazolium Bromide and Potassium Phosphate or Dipotassium Hydrogen Phosphate at 298.15 K

Abstract

Liquid-liquid equilibria (LLE) for the aqueous 1-butyl-3-methylimidazolium bromide, [C 4 mim]Br, + potassium phosphate and [C 4 mim]Br + dipotassium hydrogen phosphate systems have been determined experimentally at 298.15 K. The effect of the type of salt on the binodal and tie-lines has been studied on the basis of effective excluded volume values of the salt obtained from fitting the binodal data to the binodal model and Gibbs free energy of hydration of the constituent ions. Furthermore, the extended NRTL model has been used for the correlation of the obtained tie-line data. The six binary adjustable model parameters for this local composition model have been estimated either simultaneously from correlation of the experimental tie-line data or in the calculation; the model parameters between ionic liquid and water or between salt and water have been initially correlated with the vapor-liquid equilibrium (VLE) of the corresponding binary systems, and then those between ionic liquid and salt have been correlated with the tie-line data. The results show that good agreement was obtained with the experimental data.

Ionic Liquids in Separation Techniques

“…Several other papers have been also dealing with phase diagrams of IL-based ABS (Pei et al, 2007;Zafarani-Moattar & Hamzehzadeh, 2007;Bridges et al, 2007;Visak et al, 2007;Najdanovic-Visak et al, 2007;Wu et al, 2008a,b,c;Zhang et al, 2007Zhang et al, ,2008. Research regarding the use of IL-based ATPS has been mostly focused on the influence of inorganic salts using first of all imidazolium-based ILs.…”

Phase diagrams, densities and refractive indexes of poly(ethylene oxide)+organic salts+water aqueous two-phase systems: Effect of temperature, anion and molar mass

“…ATPSs can be formed by mixing water, in high concentration, 55-90% (w/w), with two structurally different polymers [14], or a polymer and an electrolyte [15,16], or two electrolytes [17], under specific thermodynamic conditions. Some of the important characteristics of ATPSs include low cost and toxicity, low value of interfacial tension, and high water content, which allow for a friendly environment in which solutes can be separated and purified [1,18].…”

Evaluation of Cation Influence on the Formation and Extraction Capability of Ionic-Liquid-Based Aqueous Biphasic Systems

“…[10][11][12][13] Despite the scattered results that have been reported concerning IL-based ABS, there are still many gaps in the characterization of ILs, and a general picture of the situation that would allow the finest selection of an IL is still lacking. Research regarding the use of IL-based ABS has been so far mostly centered on the influence of several inorganic salts on the phase diagrams 4,5,9,14,15 (where the ion's influence follows the well-known Hofmeister series) 13 or in the use of carbohydrates for IL-based ABS formation. [16][17][18][19] Surprisingly, one of the most interesting practical issues, evaluation of the extraction ability of those IL-based ABS, was seldom studied; only testosterone, epitestosterone, penicillin G, and opium alkaloids were previously used as partitioning solutes.…”