Extension of the UNIFAC Model for Ionic Liquids

The UNIFAC model has recently become very popular for
ionic liquids
(ILs) because of its applicability for prediction of thermodynamic
properties. This work is a continuation of our studies on the extension
of group parameters of the UNIFAC model to systems with ILs. The new
IL groups for 33 main groups and 53 subgroups were added into the
current UNIFAC parameter matrix. The parameters of group surface area
and volume for ILs were obtained by the COSMO calculation, while the
group binary interaction parameters, anm and amn, were obtained by means of correlating
the activity coefficients of solutes at infinite dilution in ILs at
different temperatures exhaustively collected from literature by the
end of 2011. The predicted results of UNIFAC model are more accurate
than those of the COSMO-RS model so that it can be used for identifying
the general relationship between molecular structure of ILs and separation
performance for the separation of liquid mixtures with ILs.