Characterization of liquid−liquid equilibrium (LLE) in systems that contain ionic liquids (ILs) is important in evaluating ILs as candidates for replacing traditional extraction and separation solvents. Although an increasing amount of experimental LLE data is becoming available, comprehensive coverage of ternary liquid-phase behavior via experimental observation is impossible. Therefore, it is important to model the LLE of mixtures that contain ILs. Experimental binary and ternary LLE data that involve ILs can be correlated using standard excess Gibbs energy models. However, the predictive capability of these models in this context has not been widely studied. In this paper, we study the effectiveness with which excess Gibbs energy models can be used to predict ternary LLE solely from binary measurements. This is a stringent test of the suitability of various models for describing LLE in systems that contain ILs. Three different excess Gibbs free energy models are evaluated:  the non-random two-liquid (N...

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Modeling Liquid−Liquid Equilibrium of Ionic Liquid Systems with NRTL, Electrolyte-NRTL, and UNIQUAC

An analytical solution, COSMOSPACE, to the statistical thermodynamics of a model of pairwise interacting surfaces, is presented. This solution was initially developed for the a priori prediction model COSMO-RS in an implicit form. A comparison of COSMOSPACE with UNIQUAC and with the quasi-chemical theory of Guggenheim reveals the conditions under which the models yield similar results and when they differ very considerably. It is shown that COSMOSPACE is in extremely good agreement with Monte-Carlo simulations for some lattice fluids (where UNIQUAC is particularly poor). The ability of COSMOSPACE to provide good fits to experimental data is shown for three binary mixtures including ethanol-cyclohexane, where UNIQUAC incorrectly predicts a liquid-liquid phase separation.

COSMOSPACE: Alternative to conventional activity‐coefficient models

http://www.rsc.org/suppdata/gc/b8/b807675h/b807675h.pdf

Extraction of alcohols from water with 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

Pervaporation separation of ethylene glycol/water mixtures through surface crosslinked PVA membranes: Coupling effect and separation performance analysis

https://www3.nd.edu/~markst/simoni_CCE_Paper.pdf

T. F. Anderson

Papers

Application of the UNIQUAC Equation to Calculation of Multicomponent Phase Equilibria. 2. Liquid-Liquid Equilibria