Correlations of Low-Pressure Carbon Dioxide and Hydrocarbon Solubilities in Imidazolium-, Phosphonium-, and Ammonium-Based Room-Temperature Ionic Liquids. Part 2. Using Activation Energy of Viscosity

This paper provides insights into the dependence of gas solubility on the viscosities of room-temperature ionic liquids (RTILs). Hildebrand solubility parameters are estimated from the activation energy of viscosity via a proportionality constant. The solubility of the gases CO2, ethylene, propylene, 1-butene, and 1,3-butadiene at low pressure and constant temperature are correlated, with the estimated RTIL Hildebrand solubility parameters, into two categories:  bis(trifluoromethyl(sulfonyl)imide ([Tf2N]) and non-bis(trifluoromethyl(sulfonyl)imide (non-[Tf2N]) RTILs. The RTILs used in this work are based on 1-alkyl-3-methylimidazolium, quaternary phosphonium, and quaternary ammonium cations. The non-[Tf2N] anions used in the trial set are chloride [Cl], hexafluorophosphate [PF6], trifluoromethanesulfonate [TfO], bis((perflurorethyl)sulfonyl)imide [BETI], dicyanamide [DCA], diethylphosphate [DEP], and dodecylbenzenesulfonate [DBS]. The analysis of the correlation parameters against theory indicates that so...