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This paper presents novel data on density, viscosity and refractive index of four binary mixtures constituted of ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate and N-methyl-2-pyrrolidone/or 1-hexanol/or liquid polyethylene glycols with molar mass 200/or 400, in the temperature range from T  = 288.15 K to 333.15 K and at pressure of p  = .1 MPa. Thermal conductivity has been measured for mixtures of ionic liquid and polyethylene glycol 200/or polyethylene glycol 400 in the temperature range from T  = 303.15 to 323.15 K and at a pressure of p  = .1 MPa. All these solutions have the potential for application in regenerative flue gas desulfurization processes. From experimental values of densities, viscosities, thermal conductivities and refractive indices, excess molar volumes and deviations in viscosity, thermal conductivity and refractive index have been calculated and correlated with Redlich-Kister polynomial equation. The values of excess and deviation functions were used for analysis of molecular interactions present in the investigated solutions. In addition, modeling of transport properties, viscosity and thermal conductivity, was carried out and the obtained results were interpreted taking into account the applied approaches and models. [ABSTRACT FROM AUTHOR]

Ternary liquid-liquid equilibria were experimentally determined for eight systems composed of an ionic liquid + n -hexane + an organic compound implicated in the racemic resolution of rac -2-pentanol ( rac -2-pentanol, vinyl butyrate, rac -2-pentyl butyrate or butyric acid) at a temperature of 303.15 K and pressure of 0.1 MPa. The following ionic liquids were used: 1-ethyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [emim + ][NTf 2 − ], and 1-hexyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [hmim + ][NTf 2 − ]. The binodal curves and the tie line of the conjugate phases compositions were determined through measurement of the refractive index for the ionic liquid-rich phase and by using gas chromatography for the hexane-rich phase, enabling their potential to be assessed for selective extraction of organic compounds from a mixture of ionic liquid reaction media for the resolution of rac -2-pentanol. Liquid phase activity coefficients were calculated using the Non-Random Two-Liquid equation and the tie line theoretical data calculated from the model are in good agreement with the experimental data. As yet, the literature contains no data for the systems studied in this paper. [ABSTRACT FROM AUTHOR]

This paper reports experimental values of dynamic viscosity for four binary systems of 1-ethyl-3-methylimidazolium tetrafluoroborate, [Emim][BF4], with dimethyl sulfoxide (DMSO), acetonitrile (ACN), ethylene glycol (EG) and 1,4-dioxane over the temperature ranges from 293.15 K to 353.15 K at p = 0.1 MPa. All binary mixtures were completely miscible over the entire range of mole fraction, except the system with 1,4-dioxane. The viscosity results have been correlated by the one parameter Grunberg–Nissan and Fang and He equations and the two-parameter McAllister, Eyring-UNIQUAC, Eyring-NRTL and Eyring-Wilson models and the results were compared. Additionally, the viscosity deviations, Δ η , and the excess Gibbs energy of activation for viscous flow, G ∗ E , were calculated and fitted to the Redlich–Kister equation. The results show that all Δ η values are negative over the whole composition range and the G ∗ E values are positive, except for the system with EG. The results of the excess functions are discussed in terms of molecular interactions. [ABSTRACT FROM AUTHOR]

This paper reports an experimental and theoretical study on the structural and energetic characterization of the 2-mercaptoimidazole (2-MI) in the solid and in the gaseous phases. The single crystal X-ray diffraction determinations on the anhydrous and hemihydrate 2-MI forms were carried out at T = (296 ± 2) K and T = (150 ± 2) K, respectively, and suggest that in both forms the 2-MI molecule is closer to the thione conformation, albeit some single bond character is possible. The energy of combustion of the title compound was measured by rotating-bomb combustion calorimetry, being used to derive the corresponding enthalpy of formation in the crystalline-phase. The enthalpy of sublimation of 2-MI, at T = 298.15 K, was obtained from high temperature Calvet microcalorimetry measurements. These two parameters yielded the gas-phase enthalpy of formation, allowing the inherent energetic analysis of the molecule. This result was discussed together with the corresponding predictions for 2-MI and its tautomer, 1,3-dihydro-2 H -imidazole-2-thione, by the G3 method. The dehydration reaction of 2-MI · 0.5H 2 O(cr) was also investigated and the corresponding enthalpy of dehydration was determined by Calvet microcalorimetry. [ABSTRACT FROM AUTHOR]

In this paper, a densimeter based on vibrating tube principle is used to determine experimentally the density of 1-butyl-2,3-dimethylimidazolium tris(pentafluoroethyl)trifluorophosphate and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide at temperatures between (278.15 and 398.15) K and at pressures up to 120 MPa. The apparatus was calibrated by using water, vacuum and bromobenzene. The Tammann–Tait equation of state was used to correlate ( p , T , ρ ) results with standard deviations around 2 · 10 −4 g · cm −3 . Other volumetric properties, such as isothermal compressibility and isobaric thermal expansivity, were obtained from this equation. For each ionic liquid, the α p isotherms present a crossing point within the experimental pressure range. Besides, the effect that the C2-methylation in the imidazolium cation provokes on density values is analyzed. The prediction ability of the group contribution methods of Gardas and Coutinho and Jacquemin et al. were tested with the experimental densities. [ABSTRACT FROM AUTHOR]

Abstract: The use of ionic liquids as a media for dissolving DNA holds great promise for the development of new base materials in electrochemistry. This paper reports the systematic study of the effect of two nucleic acid bases, uracil and adenine, on the ionicity of 1-alkyl-3-methylimidazolium acetates achieved by monitoring several thermodynamic and transport properties. Density, dynamic viscosity, speed of sound, refractive index and ionic conductivity of 1-ethyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium acetate were studied as a function of temperature at atmospheric pressure. The thermal expansion coefficients and molar volumes of these ionic liquids were calculated from the experimental density values. The various properties of the binary mixtures 1-ethyl-3-methylimidazolium acetate with uracil or adenine, namely, their ionic conductivity, density and viscosity in the temperature range 298K–343K were determined as a function of the nucleobase content. Walden plots were determined and used to clarify the role of the nucleobases in the ionic liquids ionicity. [Copyright &y& Elsevier]

Abstract: In this paper, the separation of toluene from the aliphatic hydrocarbons heptane and cyclohexane employing the ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [HMim][NTf2], 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, [HMim][TfO] and 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [BMim][TfO], as solvents was studied and discussed. Liquid–liquid equilibrium data for the ternary systems {heptane, or cyclohexane+toluene+[HMim][NTf2], or [HMim][TfO], or [BMim][TfO]} and {heptane+cyclohexane+[HMim][NTf2], or [HMim][TfO], or [BMim][TfO]} were measured at T =298.15K and atmospheric pressure. The degree of consistency of the tie-lines was tested using the Othmer–Tobias equation. The solute distribution ratio and selectivity, derived from the experimental tie-lines, were used to determine if these ionic liquids can be used as potential solvents on the extraction of toluene from aliphatic hydrocarbons; a comparison with literature data where sulfolane is used as solvent was also included. Finally, the experimental data were correlated with the NRTL and UNIQUAC thermodynamic models. [Copyright &y& Elsevier]

Abstract: In this paper, experimental densities and dynamic viscosities of 1-ethyl-3-methylimidazolium based ionic liquids (ILs) with the anions acetate and dicyanamide are presented in a wide temperature range (298.15 to 343.15K) at atmospheric pressure. Surface tension of these ILs was measured at T =298.15K. The effect of water and/or ethanol compositions on densities and dynamic viscosities of these ILs are studied in binary and ternary mixtures. A quadratic mixing rule was used to correlate binary and ternary liquid densities. The Eyring–Patel–Teja model, which is recommended for polar and aqueous systems, is used to correlate dynamic viscosity data over the whole range of compositions and temperatures in binary and ternary mixtures. Temperature-dependent interaction parameters are introduced here to account for the changes of viscosities with temperature showing good agreements with experimental data. [Copyright &y& Elsevier]

Abstract: In this paper, we demonstrate that it is possible to know the refractive index, nD , of every given mixture of 1-alkyl-3methyl imidazolium tetrafluoroborate with water and ethanol just from the knowledge of the refractive index and density of pure components. To do that, we measured nD for seven different mixtures in all range of existing concentrations and, independently, we deduce nD theoretically. Both sets of values differ less than a 0.2% on average. The theoretical deduction takes into account that these mixtures are quasi-ideal from the molar volume point of view, as recently published, and so density for any composition of the mixture can be obtained with a precision better than 0.5% from the pure compounds value. Now we simply apply Newton or Gladstone–Dale models, which relate the refractive index of a binary mixture with its density from the value of both pure components, without any fitting parameter. Both models are very similar in form and in the values they deduce (less than a 0.2% of difference), but while that of Newton performs slightly better for ethanol mixtures, the model of Gladstone–Dale gives some better results for aqueous mixtures. We think that these results can be extended to the majority of ionic liquid plus solvent systems. [Copyright &y& Elsevier]

Abstract: This paper focuses on the study of the solubility behaviour of 1-hexyl-3-methylimidazolium tetracyanoborate [HMIM][TCB] and 1-butyl-3-methylimidazolium tetracyanoborate [BMIM][TCB] in combination with methylcyclohexane and toluene as representatives for non-aromatic and aromatic components. Binary and ternary (liquid+liquid) equilibrium data were collected at three different temperatures and at atmospheric pressure (0.1MPa). The experimental data were well-correlated with the NRTL and UNIQUAC thermodynamic models; however, the UNIQUAC model gave better predictions than the NRTL, with a root mean square error below 0.97%. The non-aromatic/aromatic selectivities of the ionic liquids make them suitable solvents to be used in extractive distillation processes. [Copyright &y& Elsevier]

Abstract: In this paper, (liquid+liquid) equilibrium (LLE) data for the ternary systems (cyclohexane, or cyclooctane, or methylcyclohexane+ethylbenzene+1-ethyl-3-methylimidazolium ethylsulfate) have been determined experimentally at T = 298.15K and atmospheric pressure. The solubility curves and the tie-line compositions of the conjugate phases were obtained by means of density. The degree of consistency of the tie-lines was tested using the Othmer–Tobias equation, and the Non-Random Two-Liquid (NRTL) and the Universal Quasi-Chemical (UNIQUAC) models were used to correlate the phase equilibrium in the systems. Selectivity and solute distribution ratio were evaluated for the immiscible region. [Copyright &y& Elsevier]