Activity coefficients at infinite dilution of organic solutes in the ionic liquid PEG-5 cocomonium methylsulfate at T=(313.15, 323.15, 333.15, and 343.15)K: Experimental results and COSMO-RS predictions

Activity coefficients at infinite dilution have been determined for 25 polar and non-polar organic solutes (alkanes, cycloalkanes, alk-1-enes, alk-1-ynes, aromatic compounds, alcohols, and ketones) in the ionic liquid PEG-5 cocomonium methylsulfate with gas–liquid chromatography at four different temperatures, T = (313.15, 323.15, 333.15, and 343.15) K. Packed columns with phase loadings of 0.28 and 0.34 ionic liquid mass fraction in the stationary phase were employed to obtain values at each temperature investigated. Speed of sound, density, and refractive index values have also been measured for the pure ionic liquid at P = 0.1 MPa and T = (303.15, 313.15, 323.15, 333.15, and 343.15) K. The uncertainties in the sound speeds, densities, and refractive indices are estimated to be values of 0.9 m · s−1, 0.00003 g · cm−3, and 0.00002, respectively. Partial molar excess enthalpies at infinite dilution were calculated for the solutes from the temperature dependency of the values for the temperature range of this study. The uncertainties in the determinations of and values are 5% and 10%, respectively. Selectivity values at infinite dilution for hexane/benzene, cyclohexane/benzene, hexane/hex-1-ene, and hexane/ethanol separations have been calculated. These have been compared against values obtained from COSMO-RS predictions. ⺠values reported for 25 organic solutes in the ionic liquid PEG-5 cocomonium methylsulfate. ⺠Measurements undertaken using the g.l.c. technique at T = (313.15, 323.15, 333.15, and 343.15) K. ⺠Sound speed, density and refractive index data for ionic liquid PEG-5 cocomonium methylsulfate also reported. ⺠Measured values compared to COSMO-RS predictions.