Solubility of CO2 in 1-butyl-3-methylimidazolium diethylene-glycolmonomethylethersulfate and trihexyl(tetradecyl)phosphonium dodecyl-benzenesulfonate

This work is focused on the possible capture of carbon dioxide using ionic liquids (ILs). Such solvents are gaining special attention since the efficiency of many processes can be enhanced by the judicious manipulation of their properties. In this work, the potential use of two ILs: 1-butyl-3-methylimidazolium diethylene-glycolmonomethylethersulfate [BMIM][MDEGSO4] and trihexyl(tetradecyl)phosphonium dodecyl-benzenesulfonate [THTDP][C12H25PhSO3] is evaluated through the measurement of the liquid–vapor equilibrium in mixture with CO2 at temperatures up to 373 K and pressures up to 300 bar. Experimental data indicate that 95 g of CO2 can be absorbed per kg of ionic liquid. For each IL, the parameters of the PC-SAFT EoS were estimated using experimental density data measured under atmospheric pressure in a wide range of temperatures. After fitting a binary interaction parameter kij on experimental liquid–vapor equilibria data, the model was able to describe accurately carbon dioxide solubility in these two ionic liquids.