Screening of environmental friendly ionic liquid as a solvent for the different types of separations problem: Insight from activity coefficients at infinite dilution measurement using (gas + liquid) chromatography technique

• Activity coefficients at infinite dilution measured in the ionic liquid [EMIM]+[OS]−.
• 29 Organic solutes and water investigated at T = (318.15, 333.15, 348.15 and 358.15) K using GLC.
• Selectivities for selected separations compared to other IL’s and solvents.
• The expression and estimation of uncertainty have been described in detail.

The present work focussed on screening of the environmental friendly imidazolium-based ionic liquid for the separations of (alkane/aromatic), (alkane/alk-1-ene), (cycloalkane/aromatic) and (water/alkan-1-ol) using (gas + liquid) chromatography (GLC) technique. In this reason the activity coefficients at infinite dilution, γ13∞, for 29 organic solutes (alkanes, cycloalkanes, alkenes, alkynes, aromatics, alkanols and ketones) and water in ionic liquid 1-ethyl-3-methylimidazolium n-octylsulphate [EMIM]+[OS]− were measured at temperatures of (318.15, 333.15, 348.15 and 358.15) K. Stationary phase loadings of (23.77 and 40.76)% by mass were used to ensure repeatability of measurements. Uncertainties were determined using the law of propagation of uncertainty with an average absolute deviation of 2.53%. Density, viscosity and refractive index values were measured to confirm the purity of pure ionic liquid. Partial molar excess enthalpies at infinite dilution, ΔH1E,∞, were also determined. The selectivities, Sij∞, and capacities, kj∞, were determined for the separations of (alkane/aromatic), (alkane/alk-1-ene), (cycloalkane/aromatic) and (water/alkan-1-ol). The separating ability of the investigated ionic liquid was compared against previously investigated and industrial solvents such as sulfolane, n-methyl-2-pyrrolidine (NMP) and n-formylmorpholine (NFM).

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