Abstract
Ionic liquids with their limitless combination of cations and anions can offer an optimal solvent for a specific purpose. But not all corresponding experimental studies are possible as they will be time consuming and expensive. A judicious screening of the various possible solvents is required to select the proper ionic liquid. Conductor‐like screening model (COSMO) along with its extension to real solvents can be used for these predictions. In this work, modified version COSMO_LL has been used to predict the liquid–liquid equilibria (LLE) for 32 ternary systems, available in literature, each having an ionic liquid. A complete dissociation of cations and anions of the ionic liquid has been assumed. The root mean square deviation for all these systems is ∼9% which is excellent when compared with ∼50% obtained for predictions using the nondissociated composite molecule. Additionally, experimental LLE data has been collected for four ternary systems, namely: (a) 1‐ethyl‐3‐methylimidazolium ethylsulphate [Emim] [EtSO~4~] – Ethanol‐Hexene, (b) 1‐ethyl‐3‐methylimidazolium ethylsulphate [Emim] [EtSO~4~] – Ethanol‐Heptene, (c) 1,2‐dimethyl‐3‐ethylimidazolium ethylsulphate [E‐2,3‐dmim] [EtSO~4~] – Ethanol‐Hexene, and (d) 1,2‐dimethyl‐3‐ethylimidazolium ethylsulphate [E‐2,3‐dmim] [EtSO~4~] – Ethanol‐Heptene. The tie lines have been estimated using NMR and these have been compared with COSMO_LL predictions giving an average rmsd of ∼6%. © 2008 American Institute of Chemical Engineers AIChE J, 2008