Showing papers by "Marta Królikowska published in 2010"

Measurements of activity coefficients at infinite dilution in solvent mixtures with thiocyanate-based ionic liquids using GLC technique.

Abstract: The activity coefficients at infinite dilution, γ13∞ 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, ΔH1E,∞, were calculated from the experimental γ13∞ 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 γ13∞. Obtained values were compared to the literature values for the other ionic liquids, NMP, and sulfolane.

Density and Viscosity of Binary Mixtures of {1-Butyl-3-methylimidazolium Thiocyanate + 1-Heptanol, 1-Octanol, 1-Nonanol, or 1-Decanol}

Abstract: Density and viscosity were determined for binary mixtures containing the ionic liquid 1-butyl-3-methylimidazolium 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, Ar, the partial excess molar volumes, V1E and V2E, are presented. The Prigogine−Flory−Paterson (PFP) and the Flo...

Effect of temperature and composition on the surface tension and thermodynamic properties of binary mixtures of 1-butyl-3-methylimidazolium thiocyanate with alcohols

Abstract: The surface tensions of pure ionic liquid, 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), and binary mixtures of [BMIM][SCN] with alcohols (1-butanol, 1-pentanol, 1-hexanol) have been measured at atmospheric pressure at five temperatures in the range from 298.15 to 328.15 K. These measurements have been provided to complete information of the influence of temperature on surface tension for the selected ionic liquid, which was chosen as a possible new entrainer in extraction processes. The surface thermodynamic functions such as surface entropy and enthalpy have been derived from the temperature dependence of the surface tension values, as well as the critical temperature, parachor, and speed of sound for pure ionic liquid. The investigations include the effect of the alkyl chain length of an alcohol and polarity of a solvent on the surface tension.

Activity Coefficients at Infinite Dilution Measurements for Organic Solutes and Water in the Ionic Liquid 1-Hexyl-3-methylimidazolium Thiocyanate

Abstract: Activity coefficients at infinite dilution (γ ∞ 13 ) for 34 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, acetone, and water in the ionic liquid 1-hexyl-3-methylimidazolium thiocyanate ([hmim][SCN]) were determined by gas—liquid chromatography over temperature range from (298.15 to 368.15) K. The partial molar excess enthalpies at infinite dilution values (ΔH E,∞ i ) were calculated from the experimental γ ∞ 13 values, obtained over the temperature range. The selectivities for aliphatic/aromatic hydrocarbon separation problems were calculated from the γ ∞ 13 and compared to the literature values for other ionic liquids with a thiocyanate-based anion or a -C≡N group in an anion or a cation, N-methyl-2-pyrrolidinone (NMP) and sulfolane.

Phase Equilibria of (1-Hexyl-3-methylimidazolium Thiocyanate + Water, Alcohol, or Hydrocarbon) Binary Systems

Abstract: 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...