A 1-alkylcyanopyridinium-based ionic liquid in the separation processes

Abstract

The activity coefficients at infinite dilution, γ13∞ for 65 solutes, including wide spectra of alkanes, alkenes and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters in the 1-butyl-4-cyanopyridinium bis{(trifluoromethyl)sulfonyl}imide [BCN4Py][NTf2] were determined by gas–liquid chromatography for all solutes at seven temperatures in range of (308.15 to 368.15)K. The gas–liquid partition coefficients, KL at infinite dilution and the fundamental thermodynamic functions, the partial molar excess Gibbs energy, ΔG1E,∞, enthalpy ΔH1E,∞, and entropy term TrefΔS1E,∞ were calculated. The values of selectivity and capacity for four separation problems as hexane/hex-1-ene, hexane/benzene, cyclohexane/cyclohexene and ethylobenzene-styrene were calculated from γ13∞ and compared to literature values for bis{(trifluoromethyl)sulfonyl}imide-based ionic liquids (ILs) for the same separation problems. In comparison with the former measured ILs, the [BCN4Py][NTf2] present quite high selectivity for the chosen separation problems, and an average capacity for hex-1-ene, benzene, cyclohexene and styrene. The data presented here shows that [BCN4Py][NTf2] may be proposed as an alternative solvent for the chosen separation problems in new technological projects.