Measurements of Activity Coefficients at Infinite Dilution for Organic Solutes and Water in the Ionic Liquid 1-Butyl-1-methylpiperidinium Thiocyanate

The activity coefficients at infinite dilution (γ 13 ∞ ) for 33 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water in the ionic liquid, 1-butyl-1-methylpiperidinium thiocyanate ([BMPIP][SCN]), were determined by gas−liquid chromatography over the temperature range (318.15 to 358.15) K. The partial molar excess enthalpies at infinite dilution values (Δ H 1 E,∞ ) were calculated from the experimental γ 13 ∞ values, obtained over the temperature range. The selectivities for heptane/benzene, cyclohexane/benzene, and heptane/thiophene separation problems were calculated from the γ 13 ∞ and compared to the literature values for other ionic liquids with thiocyanate-based anion or with a butyl-methyl-substituted cation.