Solubilities of hydrofluorocarbons in ionic liquids: Experimental and modelling study

• Experimental data on the gas solubility of CHF3, CH2F2 and CH3F in room temperature ionic liquids (RTILs) at 1 atm is reported.
• CPA EoS is applied to model the solubilities of HFCs in RTILs with a good qualitative agreement.
• Semi-empirical model based on the regular-solution theory is correlated to experimental data with AAD (x2)(x2) values around 5%.
• HFCs are more soluble in [C2mim][NTf2] and [P6,6,6,14][NTf2] up to 2.5 times more than in ammonium-based RTILs.

In this work, experimental data on the gas solubility of hydrofluorocarbons (CHF3, CH2F2 and CH3F) in four room-temperature ionic liquids (RTILs) were determined within the temperature range 288 K to 308 K and at atmospheric pressure. The RTILs used were 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide([C2mim][NTf2]), (trihexyl)tetradecyl-phosphoniumbis(trifluoro-methylsulfonyl)imide ([P6,6,6,14][NTf2]), and N-methyl-2-hydroxyethylammoniumpropionate ([m-2-HEA][Pr]) and pentanoate ([m-2-HEA][P]). Two modelling approaches, which we denote as predictive and correlative, were compared. In the former, the cubic plus association equation of state (CPA EoS) is used as a predictive model to estimate the solubilities using only pure components physical properties. In the latter, the regular-solution theory is the basis to build an empirical model whose parameters are obtained through least-squares fitting of experimental values.