Michał Wlazło

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium trifluorotris(perfluoroethyl)phosphate.

The activity coefficients at infinite dilution, gamma(13)(infinity), for 37 solutes, alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water, in the ionic liquid 1-(3-hydroxypropyl)pyridinium trifluorotris(perfluoroethyl)phosphate [N-C(3)OHPY][FAP] were determined by gas-liquid chromatography at the temperatures from 308.15 to 358.15 K. The partial molar excess enthalpies at infinite dilution values DeltaH(1)(E,infinity) were calculated from the experimental gamma(13)(infinity) values obtained over the temperature range. The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated from the gamma(13)(infinity) values and compared to the literature values for other ionic liquids, N-methylpyrrolidone (NMP) and sulfolane. It was found that the investigated [N-C(3)OHPY][FAP] ionic liquid shows much higher selectivity and capacity at infinite dilution than the generally used organic solvents such as NMP, sulfolane, and other ionic liquids.

Assessment of certain ionic liquids for separation of binary mixtures based on gamma infinity data measurements

The effect of interactions between organic solvents or water on the interfacial and bulk properties of 1-benzyl-3-methylimidazolium dicyanamide, [BzMIM][DCA] and 1-benzyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [BzMIM][NTf2] were determined via measurement of activity coefficients γ∞13 at infinite dilution for 64 solutes. The data were obtained using the gas–liquid chromatography technique. Measurements were undertaken at six temperatures, in 10 K intervals, in the range of 318.15 to 368.15 K. The solutes studied included both non-polar and polar compounds, such as alkanes, alkenes, and alkynes, as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters. Density, ρ, and viscosity η, measurements for a range of temperatures, T for the chosen ionic liquids (ILs), [BzMIM][DCA] and [BzMIM][NTf2] were also undertaken at pressure, p = 101 kPa. The gas–liquid partition coefficients, KL at infinite dilution, and the fundamental thermodynamic functions, partial molar excess Gibbs energy, enthalpy and entropy at infinite dilution were calculated from the experimental data measurements. The values of selectivity and capacity for three separation cases, viz. hexane/hex-1-ene, cyclohexane/cyclohexene, and ethylbenzene/styrene were calculated from γ∞13 values and compared to literature for imidazolium-based or dicyanamide-based, or bis{(trifluoromethyl)sulfonyl}imide-based ionic liquids (ILs). The results from the study indicate that [BzMIM][DCA] has large selectivity values for all three of the separation cases studied.

Physico-Chemical Properties and Phase Behavior of the Ionic Liquid-β-Cyclodextrin Complexes

The solubility of β-cyclodextrin (β-CD) in ionic liquids (ILs) and the activity coefficients at infinite dilution ( γ13∞) of more than 20 solutes (alkanes, aromatic hydrocarbons, alcohols) were measured in four chosen ionic liquids, their mixtures with β-CD, and in the β-CD at high temperatures from 338 to 398 K using the inverse gas chromatography. The intermolecular interactions, inclusion complexes and the possible increasing of the solubility of β-CD in water using the IL are presented. The solubility of β-CD in ten chosen hydrophobic ILs at the temperature T = 423 K was detected. The solid-liquid phase diagrams (SLE) of {IL (1) + β-CD (2)} binary systems at the high mole fraction of the IL were measured for three systems (1-ethyl-3-methylimidazolium chloride, [EMIM][Cl], 1-ethyl-3-methylimidazolium bromide, [EMIM][Br]; and for 1-butyl-3-methylimidazolium chloride, [BMIM][Cl]). The eutectic points were determined at the high IL concentration for all binary systems. The intermolecular interaction and the possibility of inclusion complexes of the IL and/or solvents with β-CD were discussed. The infrared spectroscopy, IR was used for the description of the intermolecular interactions in the (β-CD + IL) systems. It was shown via the activity coefficients at infinite dilution results that the inclusion complexes are dependent on the temperature. The addition of β-CD to the IL does not improve the selectivity of the separation of the aliphatics from aromatics.