Thermodynamics and selectivity of separation based on activity coefficients at infinite dilution of various solutes in 1-allyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide ionic liquid.

The effect of interaction between organic solvents or water on the interfacial and bulk properties of 1-allyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide ([AMIM][NTf 2 ]) and on activity coefficients ( γ 13 ∞ ) at infinite dilution for 64 solutes. The observations monitored by gas-liquid chromatography at six temperatures in range of (318.15–368.15) K are explained for polar and non-polar solutes as alkanes, alkenes and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters. Density, ρ and viscosity η as a function of temperature, T for chosen ionic liquid, [AMIM][NTf 2 ] at pressure p = 101 kPa were measured. The gas-liquid partition coefficients, K L at infinite dilution and the fundamental thermodynamic functions, the partial molar excess Gibbs energy, enthalpy and entropy at infinite dilution were calculated. The values of selectivity and capacity for three separation problems as hexane/hex-1-ene, cyclohexane/cyclohexene and ethylbenzene/styrene were calculated from γ 13 ∞ and compared to literature values for imidazolium-based or bis{(trifluoromethyl)sulfonyl}imide-based ionic liquids (ILs) for the same separation problems. The data presented here show that [AMIM][NTf 2 ] reveals average selectivity in the comparison to measured earlier ILs in the chosen separation problems. These findings seem useful for future applications of ILs especially for alkanes/alkenes separation process. [ABSTRACT FROM AUTHOR]