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Imidazolium ionic liquid has been prepared from 1-methylimidazolium as a substrate. The work includes specific basic characterization of a synthesized compound by NMR spectra, water content, and a glass transition temperature determined by the differential scanning calorimetry (DSC). The mutual solubilities of 1-hexyl-3-methylimidazolium thiocyanate, [HMIM][SCN], with water, alcohols, n-alkanes (n-hexane, n-heptane, n-octane, n-nonane, or n-decane), aromatic hydrocarbons (benzene, toluene, or ethylbenzene), and cyclic hydrocarbons (cyclohexane or cycloheptane) have been measured at ambient pressure by a dynamic method in a range of temperatures from (200 to 420) K. The simple eutectic system was observed for water with complete miscibility in the liquid phase. Complete miscibility has been observed in the systems of [HMIM][SCN] with alcohols ranging from methanol to 1-decanol at a temperature of T = 298.15 K. The upper critical solution temperatures (UCSTs) were observed for the systems with n-alkanes and the lower critical solution temperatures (LCSTs) for the systems with aromatic hydrocarbons. The solubility decreases with an increase of the molecular weight of the solvent. The liquid−liquid phase equilibria (LLE) have been correlated using the nonrandom two-liquid (NRTL) equation. The average root-mean square deviation of the equilibrium mole fraction for all of the LLE data was 0.0021.

Density and viscosity were determined for binary mixtures containing the ionic liquid 1-butyl-3methylimidazolium thiocyanate ([BMIM][SCN]) and 1-alcohol (1-heptanol, 1-octanol, 1-nonanol, or 1-decanol) over the temperature range (298.15 to 348.15) K and ambient pressure. The temperature dependence of density and viscosity for these systems can be described by an empirical second-order polynomial and by the Vogel-Fucher-Tammann equation, respectively. Excess molar volumes and viscosity deviations were calculated and correlated by the Redlich-Kister polynomial expansions. These systems exhibit negative molar excess volumes. Volume expansivity and excess volume expansivity were described as functions of temperature and composition. The polynomial correlations describe the variation of density and viscosity with composition. For each system and for a chosen number of the Redlich-Kister parameters, A r , the partial excess molar volumes, V 1 E and V 2 E , are presented. The Prigogine-Flory-Paterson (PFP) and the Flory-Benson-Treszczanowicz (FBT) models were used for the prediction of V m E and H m E of the measured systems. A comparison of the results for the four binary systems elucidates the influence of 1-alcohol carbon chain length on their physical properties.

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The activity coefficients at infinite dilution, gamma13(infinity) for 34 solutes--alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, and ketones--in the ionic liquid 1-butyl-4-methylpyridinium thiocyanate, [BMPy][SCN], and in 1-butyl-1-methylpyrrolidinium thiocyanate, [BMPYR][SCN], were determined by gas-liquid chromatography at the temperature range from 298.15 to 368.15 K. The partial molar excess enthalpies at infinite dilution values, DeltaH1E,infinity, were calculated from the experimental gamma13(infinity) values obtained over the temperature range. The selectivities for the n-heptane/benzene, cyclohexane/benzene, and n-heptane/thiophene separation problems were calculated from the gamma13(infinity). Obtained values were compared to the literature values for the other ionic liquids, NMP, and sulfolane.

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