Application of [HMim][NTf2], [HMim][TfO] and [BMim][TfO] ionic liquids on the extraction of toluene from alkanes: Effect of the anion and the alkyl chain length of the cation on the LLE

• Published in: The Journal of chemical thermodynamics Vol. 53; pp. 60 - 66
• Main Authors: Corderí, Sandra, González, Emilio J., Calvar, Noelia, Domínguez, Ángeles
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2012; Elsevier
• Subjects: Aliphatic hydrocarbons; Chemical thermodynamics; Chemistry; Cyclohexane; Exact sciences and technology; General and physical chemistry; General. Theory; Heptane; Ionic liquids; Liquid–liquid equilibrium; Toluene; Ionic liquids; Liquid–liquid equilibrium; Heptane; Toluene; Cyclohexane; Liquid-liquid equilibrium
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2012.04.015

► Several ionic liquids were studied as solvent to extract toluene from heptane and cyclohexane. ► (Liquid+liquid) equilibrium data were measured at 298.15K and atmospheric pressure. ► Selectivity and solute distribution ratio were calculated and compared with those found in literature for sulfolane. ► Experimental data were correlated using NRTL and UNIQUAC thermodynamic models. In this paper, the separation of toluene from the aliphatic hydrocarbons heptane and cyclohexane employing the ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [HMim][NTf2], 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, [HMim][TfO] and 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [BMim][TfO], as solvents was studied and discussed. Liquid–liquid equilibrium data for the ternary systems {heptane, or cyclohexane+toluene+[HMim][NTf2], or [HMim][TfO], or [BMim][TfO]} and {heptane+cyclohexane+[HMim][NTf2], or [HMim][TfO], or [BMim][TfO]} were measured at T=298.15K and atmospheric pressure. The degree of consistency of the tie-lines was tested using the Othmer–Tobias equation. The solute distribution ratio and selectivity, derived from the experimental tie-lines, were used to determine if these ionic liquids can be used as potential solvents on the extraction of toluene from aliphatic hydrocarbons; a comparison with literature data where sulfolane is used as solvent was also included. Finally, the experimental data were correlated with the NRTL and UNIQUAC thermodynamic models.