Solubilities of hydrofluorocarbons in ionic liquids: experimental and modelling study

Abstract

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.