Activity Coefficients at Infinite Dilution of Alkanes, Alkenes, and Alkyl Benzenes in 1-Hexyl-3-methylimidazolium Trifluoromethanesulfonate Using Gas−Liquid Chromatography

Abstract

Activity coefficients at infinite dilution γ i ∞ have been determined for 17 organic solutes, alkanes, alkenes, and alkyl benzenes, in the ionic liquid 1-hexyl-3-methylimidazolium trifluoromethanesulfonate ([HMIM][CF 3 SO 3 ]) by the gas-liquid chromatographic (GLC) method with the ionic liquid as the stationary phase. The measurements were carried out in the temperature range of (303.15 to 363.15) K. The partial molar excess enthalpies at infinite dilution H i E,∞ were also determined for the solutes from the temperature dependence of the γ i ∞ values.

Determination of Activity Coefficients at Infinite Dilution of Organic Solutes in the Ionic Liquid 1-(2-Hydroxyethyl)-3-methylimidazolium Nonafluoro-1-butanesulfonate Using Gas–Liquid Chromatography

“…The lower the value of the capacity, the smaller the amount of solute that dissolves in the solvent, causing the separation less efficiency. Disubstituted imidazolium based ionic liquids as a class of solvents for extraction and separation processes have been broadly studied in the literature. − ,,− Reviews on the properties and applications of such ionic liquids are available for details. , In general, protic ionic liquids with Brønsted acidity are not preferred as separation media because they may catalyze undesired reactions for molecules of interest to be separated.…”

“…ILs which have shown great potential for the separation of cyclohexane/benzene by extractive distillation or extraction are exemplified by those in the literature: s ij ∞ = 38.9 (at 298.15 K) for [EMIM]­[BF 4 ]; s ij ∞ = 33.2 (at 298.15 K) for [EMIM]­[SCN]; s ij ∞ = 21.7 (at 298.15 K) for [EMIM]­[C 2 H 5 SO 4 ]; s ij ∞ = 19.7 (at 298.15 K) for [BMIM]­[BF 4 ]; s ij ∞ = 10.2 (at 298.15 K) for [BMIM]­[Tf 2 N]; s ij ∞ = 29.3 (at 298.15 K) for [BMIM]­[SCN]; s ij ∞ = 7.8 (at 298.15 K) for [HMIM]­[CF 3 SO 3 ]; s ij ∞ = 7.4 (at 298.15 K) for [HMIM]­[NTf 2 ]; s ij ∞ = 53.6 (at 323.15 K) for [C 2 OHmim]­[BF 4 ]; , s ij ∞ = 15.8 (at 323.15 K) for [C 2 OHmim]­[FAP] . Generally, the selectivity for the separation of aromatic hydrocarbons/aliphatic hydrocarbons decreases with increasing length of the alkyl chain on the imidazolium, or anion of the IL.…”

Activity Coefficients at Infinite Dilution of Organic Solutes in 1-Ethyl-3-methylimidazolium Tetrafluoroborate Using Gas−Liquid Chromatography

“…[1][2][3][4][5][6][7] Heintz et al [8][9][10][11][12][13][14][15][16] and Letcher et al [17][18][19][20][21][22][23][24][25] measured γ i ∞ of various solutes in a number of ILs.…”

Activity Coefficients at Infinite Dilution and Physicochemical Properties for Organic Solutes and Water in the Ionic Liquid 1-Ethyl-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate

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Fig. 2 Comparison of selectivity, S 12 ∞ , at T = 328.15 K for hexane/benzene separation problem of different 1-alkyl-3-methylimidazolium ionic liquids: ( filled circle ) [FAP] − this work and [ 22 ], ( empty circle ) [FAP] − [ 21 , 22 ], ( empty square ) [NTf 2 ] − [ 10 , 29 – 31 ]; ( empty triangle ) [TCB] − [ 11 , 32 , 33 ], ( filled triangle ) [CF 3 SO 3 ] − [ 14 , 34 , 35 ], ( filled square ) [BF 4 ] − [ 18 , 36 – 39 ], where alkyl = n -C n H 2 n +1 . The lines are drawn to guide the eye

Fig.

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