Excess Molar Gibbs Free Energies Research Articles

Intermolecular interactions in mixtures of poly (ethylene glycol) with methoxybenzene and ethoxybenzene: Volumetric and viscometric studies

The density and viscosity values of the binary mixtures of {poly (ethylene glycol) (PEG400)+methoxybenzene, or+ethoxybenzene} have been measured at T=(298.15, 308.15, and 318.15)K. From these experimental values, the excess molar volume, apparent specific volume, partial specific volume of solute, partial specific volume of solvent and excess Gibbs free energy of activation have been computed over the entire range of composition at three temperatures. From the experimental data, the thermodynamic functions of activation have been estimated for each binary mixture. The obtained results have been interpreted in light of polymer–solvent interactions and packing effects. The signs of excess molar volume and deviations of excess Gibbs free energy of activation have been used to obtain some information in regard to existence of specific interactions between PEG400 and solvents molecules. The changes in entropy and enthalpy of activation from the initial state to the transition state were also calculated in order to see which one of these functions controls viscous flow process in the studied polymer solutions. The excess molar volume and excess Gibbs free energy of activation values have been adequately fitted to the Redlich–Kister polynomial. Apparent specific volume values were correlated with the suitable equation. The different models proposed for correlating the viscosity of polymer solutions or liquid mixtures (segment-based-Eyring–NRTL, segment-based-Eyring–Wilson, Grunbreg–Nissan, Frenkel, Hind et al., Katti–Chauddhri, Tamura–Kurata, Auslander and McAllister) have also been used to fit the viscosity values.

Densities, viscosities, refractive indices and excess properties of ortho- and meta-chloroaniline with 2-alkoxyethanols at 303.15 K

Densities (ρ), viscosities (η) and refractive indices (nD) were measured for the binary mixtures of o- and m-chloroaniline with 2-alkoxyethanols like 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol at 303.15K. From the experimental data, the values of excess molar volume (VE), deviation of viscosity (ηE), deviation of refractive index (ΔnD), excess molar refraction (RmE) and excess Gibbs free energy (ΔG⁎E) for the six binary mixtures were calculated and the values are fitted with Redlich–Kister polynomial equation. The values of all calculated parameters of the binary mixtures and their deviations indicate a strong specific type of interaction between the amino group (NH2) of chloroanilines with hydroxyl group (OH) of 2-alkoxyethanols.

The study of activity coefficients at infinite dilution for organic solutes and water in 1-butyl-4-methylpyridinium dicyanamide, [B4MPy][DCA] using GLC

The main aim of this paper is to investigate the possibility of using ionic liquid as a solvent for the separation processes, especially for extraction of azeotropic mixtures i.e. aliphatic from aromatic hydrocarbons. The first step in assessing the ability of selective extraction is to determine the selectivity based on measurements of activity coefficients at infinite dilution. In this work new data of the activity coefficients at infinite dilution for 53 solutes including: alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, acetonitrile, pyridine, 1-nitropropane and water in the ionic liquid: 1-butyl-4-methylpyridinium dicyanamide, [B4MPy][DCA] were determined using GLC technique at wide temperature range from (308.15 to 368.15)K. From the temperature dependence of γ13∞ the partial molar excess Gibbs free energies, ΔG1E,∞, enthalpies ΔH1E,∞ and entropies TrefΔS1E,∞ at infinite dilution were calculated. Additionally the (gas+liquid) partition coefficients, KL were determined. The selectivities for the many separation problems were calculated and compared to the values from the recent literature for other ionic liquids. The densities of pure ionic liquid were determined over a wide temperature range from (308.15 to 368.15)K.

Thermodynamics and activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-butyl-1-methylmorpholinium tricyanomethanide

The activity coefficients at infinite dilution, γ13∞, for 61 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, esters, aldehyde, acetonitrile, pyridine and 1-nitropropane in the ionic liquid (IL) 1-butyl-1-methylmorpholinium tricyanomethanide, [BMMOR][TCM] were determined by gas–liquid chromatography at six temperatures within the range of (318.15 to 368.15)K. The thermodynamic functions at infinite dilution as partial molar excess Gibbs free energy ΔG1E,∞, enthalpy ΔH1E,∞, and entropy term TrefΔS1E,∞ were calculated from the experimental γ13∞ values obtained over the temperature range. The density of [BMMOR][TCM] was measured over the temperature range (288.15 to 368.15)K. The gas–liquid partition coefficient KL was calculated for all solutes. The values of selectivity and capacity for a few separation problems such as hexane/benzene, cyclohexane/benzene, heptane/thiophene at T=328.15K were calculated from γ13∞ and compared to literature values for similar ionic liquids, viz. N-methyl-2-pyrrolidinone (NMP), and sulfolane. In comparison with the previously measured values for [BMPYR][TCM], the morpholinium IL presents high selectivity for the separation of aromatic hydrocarbons from aliphatic hydrocarbons, and especially thiophene, or piridine from heptane with a slightly lower capacity. New data show that [BMMOR][TCM] IL may be proposed as an alternative solvent for the separation of sulphur or nitrogen compounds from alkanes.

Measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide

The activity coefficients at infinite dilution, γ13∞, for 62 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, acetonitrile, pyridine and 1-nitropropane in the ionic liquid 1-butyl-1-methylpyrrolidinium tricyanomethanide, [BMPYR][TCM] were determined by gas–liquid chromatography at six temperatures over the range of (318.15 to 368.15)K. The partial molar excess Gibbs free energy, ΔG1E∞, enthalpy ΔH1E∞, and entropy term TrefΔS1E,∞ at infinite dilution were calculated from the experimental γ13∞ values obtained over the temperature range. The densities of [BMPYR][TCM] were measured within temperature range from 318.15K to 368.15K. The gas–liquid partition coefficients, KL were calculated for all solutes. The values of selectivity for few separation problems as hexane/benzene, cyclohexane/benzene, heptane/thiophene were calculated from γ13∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other ionic liquids based on [BMPYR]+ cation. In comparison with the former measured ILs, [BMPYR][TCM] present quite high selectivity for the separation of aromatic hydrocarbons and aliphatics hydrocarbons, an average capacity for benzene. The data presented here shows that [BMPYR][TCM] ionic liquid can be used as an alternative solvent for the separation of thiophene from the aliphatic hydrocarbons.

Environmentally friendly solutions of liquid poly(ethylene glycol) and imidazolium based ionic liquids with bistriflamide and triflate anions: Volumetric and viscosity studies

In this paper, densities and viscosities of the solutions of PEG200 with two imidazolium ionic liquids, 1-ethyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide ([C2mim][NTf2]) and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([C2mim][OTf]), at pressure 0.1MPa and in the temperature range of 288.15–318.15K, were measured. The experimental data were used to calculate excess molar volumes, deviations in viscosity and excess molar Gibbs free energies of activation of viscous flow for the studied solutions. Excess molar volumes indicate strong attractive interactions provoked by the studied ionic liquids which are even enhanced in the case of the [C2mim][OTf] as a solution component. The analysis of the viscosity data showed that these cannot be solely explained on the basis of the interactions between the present molecules/ions and that the factors also related to entropy – size and packing of molecules – must be considered as well. Thus, excess molar Gibbs free energy of activation of viscous flow appeared as very important for a complete description of the current viscosity behavior.

Measurements of activity coefficients at infinite dilution for organic solutes and water in N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] using GLC

This work is a continuation of our research of ionic liquids (ILs) to investigate the possibility of using them as a solvent for the separation processes, especially for extraction of aromatic from aliphatic hydrocarbons. New data of the activity coefficients at infinite dilution, γ13∞ were determined for 53 solutes including: n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, acetonitrile, pyridine, 1-nitropropane and water in the ionic liquid: N-hexylisoquinolinium thiocyanate, [HiQuin][SCN] using inverse gas chromatography at wide range of temperature from (308.15 to 368.15)K. From the temperature dependence of γ13∞ the basic thermodynamic function, that is partial molar excess Gibbs free energies, ΔG1E,∞, enthalpies ΔH1E,∞ and entropies TrefΔS1E,∞ at infinite dilution were calculated at a wide temperature range. Additionally the gas–liquid partition coefficients, KL were determined. The selectivities for n-heptane/toluene, cyclohexane/benzene, n-heptane/xylenes separation problems were calculated directly from the experimental values of γ13∞ and compared to the studies from the recent literature for other ionic liquids.

Activity coefficient at infinite dilution measurements for organic solutes (polar and non-polar) in fatty compounds – Part II: C18 fatty acids

In this work, activity coefficients at infinite dilution (γ13∞) have been measured for 21 solutes (subscript 1) (alkanes, cycloalkanes, alkenes, aromatic compounds, alcohols, esters, ketones, and halogenated hydrocarbons), in four solvents (subscript 3), namely one saturated fatty acid and three unsaturated fatty acids: stearic (octadecanoic) acid – C18:0, oleic (cis-9-octadecenoic) acid – C18:1 9c, linoleic (cis,cis-9,12-octadecadienoic) acid – C18:2 9c12c, and linolenic (cis,cis,cis-9,12,15-octadecatrienoic) acid – C18:3 9c12c15c, by gas–liquid chromatography. The measurements were carried out at temperatures from (303.13 to 368.19)K and the partial molar excess Gibbs free energy (ΔG1E,∞), enthalpy (ΔH1E,∞), and entropy (ΔS1E,∞), at infinite dilution were calculated from experimental γ13∞ values obtained over the temperature range. The uncertainties in determination of γ13∞ and ΔH1E,∞ are 4% and 20%, respectively. The results for stearic acid obtained in this study have been compared to those available in the Dortmund Data Bank (DDB). The real behaviour of fatty systems could be better understood through the results obtained in this work.

Physicochemical properties and activity coefficients at infinite dilution for organic solutes and water in a novel bicyclic guanidinium superbase-derived protic ionic liquid

The activity coefficient at infinite dilution, γ13∞, was determined by gas–liquid chromatography at temperatures from T=308.15 to T=348.15K for 54 assorted solutes—among them, alkanes (linear, branched, or cyclic), alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, tetrahydrofuran, 1,4-dioxane, ethers, acetone, ketones, acetonitrile, pyridine, and 1-nitropropane—in the novel bicyclic guanidine superbase-derived protic ionic liquid 1,3,4,6,7,8-hexahydro-1-methyl-2H-pyrimido[1,2-a]pyrimidine bis(pentafluoroethyl)sulfonylimide, [MTBDH][BETI]. The partial molar excess Gibbs free energy ΔG1E,∞, the partial molar excess enthalpy ΔH1E,∞, and entropy at reference temperature TrefΔS1E,∞ at infinite dilution were calculated from the experimental γ13∞ values obtained over this temperature range. The gas–liquid partition coefficient, KL, was calculated for each solute and discussed in light of the Abraham solvation parameter model. The density of the IL as a function of temperature was also measured. The selectivities for heptane/benzene, heptane/thiophene, heptane/pyridine, and heptane/nitropropane separation problems were calculated from γ13∞ and compared to literature values for select ILs, as these separation problems are central to the petroleum industry.

Density, dynamic viscosity and derived properties of binary mixtures of m-xylene, o-xylene, and p-xylene, with pyridine at T = 293.15, 303.15, 313.15 and 323.15 K

Densities, viscosities of binary liquid mixtures of pyridine and m-xylene, o-xylene and p-xylene were determined at 293.15, 303.15, 313.15 and 323.15K. From the experimental results obtained, deviation in viscosity (Δη), excess molar volume (VE), and excess Gibbs free energy of activation of viscous flow (ΔG*E), were determined. The deviations in viscosity, excess molar volume and excess Gibbs free energy of activation of viscous flow were correlated with Redlich–Kister polynomial equation. Other parameters like Grunberg–Nissan interaction constant (d′) and a modified Kendall–Monroe equation (Eηm), were used to quantitatively analyze the interactions in the system.

Interdiffusion, Intrinsic Diffusion, Atomic Mobility, and Vacancy Wind Effect in γ(bcc) Uranium-Molybdenum Alloy

U-Mo alloys are being developed as low enrichment uranium fuels under the Reduced Enrichment for Research and Test Reactor (RERTR) Program. In order to understand the fundamental diffusion behavior of this system, solid-to-solid pure U vs Mo diffusion couples were assembled and annealed at 923 K, 973 K, 1073 K, 1173 K, and 1273 K (650 °C, 700 °C, 800 °C, 900 °C, and 1000 °C) for various times. The interdiffusion microstructures and concentration profiles were examined via scanning electron microscopy and electron probe microanalysis, respectively. As the Mo concentration increased from 2 to 26 at. pct, the interdiffusion coefficient decreased, while the activation energy increased. A Kirkendall marker plane was clearly identified in each diffusion couple and utilized to determine intrinsic diffusion coefficients. Uranium intrinsically diffused 5-10 times faster than Mo. Molar excess Gibbs free energy of U-Mo alloy was applied to calculate the thermodynamic factor using ideal, regular, and subregular solution models. Based on the intrinsic diffusion coefficients and thermodynamic factors, Manning’s formalism was used to calculate the tracer diffusion coefficients, atomic mobilities, and vacancy wind parameters of U and Mo at the marker composition. The tracer diffusion coefficients and atomic mobilities of U were about five times larger than those of Mo, and the vacancy wind effect increased the intrinsic flux of U by approximately 30 pct.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpiperidinium trifluorotris(perfluoroethyl)phosphate

This work is continuation of our systematic study of activity coefficients at infinite dilution, γ∞ of different organic solutes and water in the ionic liquids. New data of γ∞ were determined for 62 solutes, including alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, butanal, acetonitrile, and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpiperidinium trifluorotris(perfluoroethyl)phosphate by inverse gas chromatography at the temperature range from (318.15 to 368.15)K. The basic thermodynamic functions, namely partial molar excess Gibbs free energies, ΔG1E,∞, enthalpies, ΔH1E,∞ and entropies, ΔS1E,∞ at infinite dilution were calculated from the experimental γ∞ values obtained over the temperature range. Additionally the gas–liquid partition coefficients, KL were determined. Results are compared to previously investigated ionic liquids with the same cations or anions. Values of the selectivity and capacity at infinite dilution for heptane/benzene, heptane/thiophene, and heptane/methanol extraction problems were calculated from experimental γ∞ values to verify the possibility of investigated ionic liquid as an entrainer in liquid–liquid extraction.

Densities, viscosities, refractive indices and excess properties of aniline and o-anisidine with 2-alkoxyethanols at 303.15K

Densities, viscosities and refractive indices have been measured for the binary mixtures of aromatic amines such as aniline and o-anisidine with 2-alkoxyethanols like 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol at 303.15 K. The excess properties are excess molar volume (VE), deviation of viscosity (ηE), deviation of refractive index (ΔnD), excess molar refraction (RmE) and excess Gibbs free energy (ΔG* E) for the six binary mixtures that were calculated and the values are fitted with Redlich–Kister polynomial equation. The measured refractive index values are analyzed by different theoretical mixing rules and the standard deviations are predicted. From the values of excess properties of the binary mixtures and its deviations indicate that a strong specific type of interaction is formed between the amino group (–NH2) of aniline and o-anisidine with hydroxyl group (–OH) of 2-alkoxyethanols. The strength of interaction is in the following order: aniline > o-anisidine in 2-alkoxyethanols (2-BE > 2-EE > 2-ME). Further the hydrogen bonding interaction of anilines with 2-alkoxyethanols is confirmed by FT-IR spectra.

Activity coefficient at infinite dilution measurements for organic solutes (polar and non-polar) in fatty compounds: Saturated fatty acids

The activity coefficients at infinite dilution , γ13∞ (the subscript 1 and 3 correspond to solute and solvent, respectively), for 21 solutes, including alkane, cycloalkane, alkene, aromatic compounds, alcohol, ester, ketone, and halogenated hydrocarbons, in four solvents, that are the saturated fatty acids: capric (decanoic) acid, lauric (dodecanoic) acid, myristic (tetradecanoic) acid, and palmitic (hexadecanoic) acid, were determined by gas–liquid chromatography at temperatures from 314.10K to 358.33K. Comparison with previously published for selected solutes in palmitic (hexadecanoic) acid were also performed. The values of the partial molar excess Gibbs free energy, ΔG13∞, enthalpy, ΔH13∞, and entropy, ΔS13∞, at infinite dilution were calculated from experimental γ13∞ values obtained over the temperature range. Results obtained in this work allow a more accurate description of the real behavior of fatty systems.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 4-(2-methoxyethyl)-4-methylmorpholinium trifluorotris(perfluoroethyl)phosphate

This paper presents new data on activity coefficients at infinite dilution, γ∞ for 62 different solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water in the ionic liquid 4-(2-methoxyethyl)-4-methylmorpholinium trifluorotris(perfluoroethyl)phosphate, [COC2mMOR][FAP]. The data were determined by inverse gas chromatography at six temperatures from T=318.15K to T=368.15K. These values were compared with ionic liquid based on the same cation and bis(trifluoromethylsulfonyl)-amide anion, [COC2mMOR][NTf2]. Additionally the partial molar excess Gibbs free energies ΔG1E,∞, enthalpies ΔH1E,∞, and entropies ΔS1E,∞ at infinite dilution were calculated from the experimental γ∞ values obtained over the temperatures range. The selectivities and capacities at infinite dilution for hexane/benzene, cyclohexane/benzene, and heptane/thiophene extraction problems were calculated from the γ∞ to verify the possibility of investigated ionic liquid as an entrainer in liquid–liquid extraction and desulphurization of fuels. Obtained values were compared with literature data of other ionic liquids based on trifluorotris(perfluoroethyl)phosphate and bis(trifluoromethylsulfonyl)-amide anions and industrial solvents: NMP and sulfolane. Also the Abraham solvation parameter model was used for evaluation of the solvation characteristic of the ionic liquid. Linear free energy relationship (LFER) system constants as a function of temperature were calculated.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)-amide

The activity coefficients at infinite dilution, γ∞, gas–liquid partition coefficients, KL, the partial molar excess Gibbs free energy ΔG1E,∞, enthalpy ΔH1E,∞ and entropy ΔS1E,∞ at infinite dilution for 61 organic solutes and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)-amide were determined by inverse gas chromatography at the temperatures from (318.15 to 368.15)K. The values of the selectivity for selected compounds which form azeotropic mixtures were calculated from the γ∞ and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion.

Measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate

The activity coefficients at infinite dilution, γ13∞, for 43 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, acetonitrile, pyridine, and 1-nitropropane in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate [EMIM][MeSO3] were determined by gas–liquid chromatography at six temperatures within the range (308.15 to 358.15)K. The interaction of these 42 organic compounds and water with the ionic liquid were described with the partial molar excess Gibbs free energy, ΔG1E,∞, enthalpy ΔH1E,∞, and entropy TrefΔS1E,∞ at infinite dilution, calculated from the experimental γ13∞ values obtained over the temperature range. The gas–liquid partition coefficients, KL were calculated for all solutes. The values of the selectivity for few separation problems as heptane/toluene, cyclohexane/benzene, heptane/xylenes and heptane/thiophene were calculated from γ13∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other ionic liquids based on [EMIM]+ cation. Comparison with the results published earlier for [EMIM][MeSO3] show much lower selectivities in the discussed separation problems. By contrast with the former measured ILs [EMIM][MeSO3] reveals the average selectivity for the separation of aromatics/aliphatics and low capacity for benzene. An interesting high value of selectivity was observed in the separation of thiophene/aliphatics. Very high values of selectivity may be expected in the separation of the azeotropic systems including water. The density of [EMIM][MeSO3] within temperature range from (298.15 to 358.15)K was measured and compared to the literature values.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide

The activity coefficients at infinite dilution, γ∞ and gas–liquid partition coefficients, KL for 61 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, butanal, acetonitrile, and water in the ionic liquid 1-(2-methoxyethyl)-1-methylpiperidinium bis(trifluoromethylsulfonyl)-amide were determined by inverse gas chromatography at the temperatures from (318.15 to 368.15)K. The partial molar excess Gibbs free energies ΔG1E,∞, enthalpies ΔH1E,∞ and entropies ΔS1E,∞ at infinite dilution were calculated from the experimental γ∞ values obtained over the temperature range. The selectivities for selected compounds, which form azeotropic mixtures, were calculated from the γ∞ and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 4-(2-methoxyethyl)-4-methylmorpholinium bis(trifluoromethylsulfonyl)-amide

The activity coefficients at infinite dilution, γ 13 ∞ and gas–liquid partition coefficients, K L for 62 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, butanal, acetonitrile, acetic acid and water in the ionic liquid 4-(2-methoxyethyl)-4-methylmorpholinium bis(trifluoromethylsulfonyl)-amide were determined by gas–liquid chromatography at the temperatures from (318.15 to 368.15) K. The partial molar excess Gibbs free energies Δ G 1 E, ∞ , enthalpies Δ H 1 E, ∞ and entropies Δ S 1 E, ∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for selected compounds which form azeotropic mixtures were calculated from the γ 13 ∞ and compared to the literature values for other ionic liquids based on bis(trifluoromethylsulfonyl)-amide anion.

Measurements of activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate

The activity coefficients at infinite dilution, γ 13 ∞ , for 59 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, acetic acid, thiophene, ethers, ketones, esters, butanal 4, and acetonitrile in the ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate, [HMIM][TCB], were determined by gas–liquid chromatography at six temperatures over the range (318.15 to 368.15) K. The partial molar excess Gibbs free energies Δ G 1 E, ∞ , enthalpies Δ H 1 E, ∞ , and entropies Δ S 1 E, ∞ at infinite dilution were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The gas–liquid partition coefficients, K L were calculated for all solutes. The selectivities for different separation problems were calculated from γ 13 ∞ and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and other tetracyanoborate-based ionic liquids. The densities of [HMIM][TCB] within the temperature range from 318.15 K to 368.15 K were measured.