Measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate

The activity coefficients at infinite dilution, γ13∞, for 59 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, acetic acid, thiophene, ethers, ketones, esters, butanal 4, and acetonitrile in the ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate, [HMIM][TCB], were determined by gas–liquid chromatography at six temperatures over the range (318.15 to 368.15) K. The partial molar excess Gibbs free energies ΔG1E,∞, enthalpies ΔH1E,∞, and entropies ΔS1E,∞ at infinite dilution were calculated from the experimental γ13∞ values obtained over the temperature range. The gas–liquid partition coefficients, KLKL were calculated for all solutes. The selectivities for different separation problems were calculated from γ13∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other tetracyanoborate-based ionic liquids. The densities of [HMIM][TCB] within the temperature range from 318.15 K to 368.15 K were measured.

► Measurements of activity coefficients at infinite dilution using GLC. ► Fifty-nine organic solvents and water in the ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate, [HMIM][TCB]. ► Possible entrainer for different separation processes. ► The excess thermodynamic functions and the gas–liquid partition coefficients were calculated.