The ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate revisited: Solubility of carbon dioxide over an extended range of temperature and pressure

Abstract Solubility data of carbon dioxide (CO2) in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate [EMIM][CH3SO3] at T = (273.15 to 413.15) K and pressures up to p = 5.0 MPa are reported. The solubility measurements were carried out using an isochoric method which operates in decrements of ΔT = 20 K within the investigated temperature range and at selected four different pressure steps ranging from a pressure p of around 5.0 MPa down to around 0.4 MPa. The solubility of CO2 in the ionic liquid monotonously decreases with increasing temperatures at a constant pressure. Within the p,T-range investigated, CO2 displayed a solubility in [EMIM][CH3SO3] from a mole fraction x = 0.0160 mol·mol−1 and a corresponding molality m = 0.0791 mol·kg−1 at T = 413.15 K and p = 0.432 MPa up to x = 0.4049 mol·mol−1 and m = 3.2982 mol·kg−1 at T = 293.15 K and p = 4.577 MPa. Henry's law constant was calculated from the solubility data reported here, and literature data were reviewed for comparison. Additionally, thermodynamic state properties that can be derived from Henry's law constant, such as the Gibbs energy of solvation ΔsolG, the enthalpy of solvation ΔsolH, the entropy of solvation ΔsolS, and the heat capacity of solvation ΔsolCp, were calculated.