Gas Solubility in Ionic Liquids: UNIFAC-IL Model Extension

Prediction
of thermodynamic behavior is essential for the early
design stage of separation processes including solvent selection,
process optimization, and its performance evaluation. In order to
better utilize ionic liquids (ILs) as solvents in gas separation processes,
the UNIFAC-IL model of IL–liquid solute systems is extended
to IL–gas systems by using experimental data from published
works and pseudo-experimental data specifically generated from a calibrated
COSMO-RS model. In this work, we consider in the model development
a total number of 100 ILs from 6 cation families (i.e., imidazolium,
pyridinium, pyrrolidinium, ammonium, phosphonium, and guanidium),
24 anion families [i.e., bis­(trifluoromethanesulfonyl)­amide, tetrafluoroborate,
hexafluorophosphate, dimethylphosphate, heptafluorobutyrate, trifluoroacetate,
trifluoromethanesulfonate, methylsulfonate, methylsulfate, ethylsulfate,
nitrate, p-toluenesulfonate, 2-(2-methoxyethoxy)­ethylsulfate,
chloride, bromide, dicyanamide, tetracyanoborate, tris­(pentafluoroethyl)­trifluorophosphate,
lactate, levulinate, saccharinate, succinamate, tetrafluoroethanesulfonate,
bis­(2,4,4-trime-thylpentyl)­phosphinate], and 13 gases including CO2, SO2, H2S, NH3, N2O, CO, N2, O2, H2, CH4, C2H4, C2H6, and C3H8. The extended UNIFAC-IL-Gas model consists of
two submodels, namely, the UNIFAC-IL-Gas (Exp.) model and the UNIFAC-IL-Gas
(Pseudo-Exp.) model. The training and testing of the UNIFAC-IL-Gas
(Exp.) model is based on 100% experimental data, while the training
of the UNIFAC-IL-Gas (Pseudo-Exp.) model is based on pseudo-experimental
data, but its testing is also based on 100% experimental data.