Solubility of hydrofluorocarbons in phosphonium-based ionic liquids: Experimental and modelling study

• Gas solubilities of CHF3, CH2F2 and CH3F in phosphonium-based ILs measured at 1 atm.
• CHF3, CH2F2 more soluble in [P4,4,4,2][(C2)2PO4] while CH3F is in [P6,6,6,14][Cl].
• Solubility of HFC/RTIL systems were modelled using CPA-EoS and RST.
• CPA-EoS describes well the experimental data with ARDs of 3.5% using a 2B scheme.
• Negative enthalpy and entropy of solvation is observed for all HFC/RTIL systems.

In this work, experimental values of gas solubility of hydrofluorocarbons (CHF3, CH2F2 and CH3F) in three room-temperature ionic liquids (RTILs) were determined within the temperature range 288 K to 308 K and at atmospheric pressure. The RTILs used were trihexyltetradecylphosphonium chloride ([P6,6,6,14][Cl]), tributyl(methyl)phosphonium methylsulfate ([P4,4,4,1][C1SO4]), and tributyl(ethyl)phosphonium diethylphosphate ([P4,4,4,2][(C2)2PO4]). The data gathered have been modelled using two approaches: the Cubic plus Association equation of state (CPA EoS) and the regular-solution theory (RST). The experimental measurements were then discussed critically and the modelling results compared.