Physicochemical properties and activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-decyl-3-methylimidazolium tetracyanoborate.

The activity coefficients at infinite dilution γ(13)(∞) and gas−liquid partition coefficients K(L) for 43 solutes—alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, carboxylic acids, thiophene, ethers, ketones, and water—in the ionic liquid 1-decyl-3-methylimidazolium tetracyanoborate ([dmim][TCB]) were determined by gas−liquid chromatography at temperatures from 318.15 to 378.15 K. The partial molar excess Gibbs energies ΔG(1)(E,∞), enthalpies ΔH(1)(E,∞), and entropies ΔS(1)(E,∞) at infinite dilution were calculated from the experimental γ(13)(∞) values obtained over the temperature range. Additionally, the densities for investigated ionic liquid over the temperature range were determined. The selectivities for the aliphatic/aromatic hydrocarbon separation problem were calculated from γ(13)(∞) and compared to the literature values for N-methyl-2-pyrrolidinone (NMP) and sulfolane. It was found that the investigated [dmim][TCB] ionic liquid shows much higher capacity than NMP and sulfolane and selectivity on the same level as NMP and lower than that for sulfolane for the separation of aliphatic hydrocarbons from aromatic hydrocarbons.