Values Of Partial Molar Excess Enthalpies Research Articles

Measurements of activity coefficient at infinite dilution for organic solutes in tetramethylammonium chloride + ethylene glycol deep eutectic solvent using gas-liquid chromatography

Deep eutectic solvents (DESs) are considered as the new ionic liquids (ILs) analogues that have emerged as potential alternative ‘green’ solvents, for a diversity of applications. In this study, a type III DES based on ammonium salt was investigated as an alternative solvent to currently employed conventional organic solvents in separation processes. Activity coefficients at infinite dilution, γ13∞ for 19 organic solutes in the tetramethylammonium chloride + ethylene glycol DES were measured by the gas-liquid chromatography (GLC) method at four temperatures in the range from (313.15–343.15) K. Experimental measurements were undertaken with an overall uncertainty of ±5.4%. The effect of the structure of the solutes on γ13∞ was also investigated. For all investigated solutes, Gibbs helmholtz relationship was utilised to derive partial molar excess enthalpy values at infinite dilution (ΔHiE,(∞)) from experimental limiting activity coefficient data. From selectivity (Sij∞) and capacity (kj∞) values at infinte dilution, it was concluded that the investigated DES has the potential to replace a number of industrial solvents for the separation of various industrial mixtures.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid trihexyltetradecylphosphonium hexafluorophosphate using gas–liquid chromatography at T = (313.15, 333.15, 353.15, and 363.15) K

Activity coefficients at infinite dilution γ13∞ for 31 organic solutes (n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, alcohols, and ketones) in the ionic liquid trihexyltetradecylphosphonium hexafluorophosphate [3C6C14P][PF6] were determined by gas–liquid chromatography at T=(313.15, 333.15, 353.15, and 363.15)K. From experimental values, the partial molar excess enthalpy values at infinite dilution, ΔH1E,∞, together with the selectivity, Sij∞, and the capacity, kj∞, (which are related to the separation of liquids) were calculated and compared to literature values for other ionic liquids, as well as industrial solvents.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-butyl-3-methylimidazolium hexafluoroantimonate using gas–liquid chromatography at T = (313.15, 323.15, and 333.15) K

Activity coefficients at infinite dilution were determined for 27 solutes: n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, alcohols, and ketones in the ionic liquid 1-butyl-3-methylimidazolium hexafluoroantimonate, [BMIM][SbF 6], by gas–liquid chromatography at three different temperatures, T = (313.15, 323.15, and 333.15) K. The results are compared to published data on related compounds. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental data over the same temperature range. Selectivities and capacities at infinite dilution were calculated for the hexane/benzene and methanol/benzene systems from experimental infinite dilution activity coefficients and compared to the literature values for related ionic liquids, as well as to data on industrial molecular solvents.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid trihexyl(tetradecyl)phosphonium tetrafluoroborate using gas–liquid chromatography at T = (313.15, 333.15, 353.15, and 373.15) K

Activity coefficients at infinite dilution have been measured by gas–liquid chromatography for 27 organic solutes (n-alkanes, 1-alkenes, 1-alkynes, cycloalkanes, aromatics, alcohols, and ketones) in the ionic liquid trihexyl(tetradecyl)phosphonium tetrafluoroborate [3C 6C 14P][BF 4]. The measurements were carried out at four different temperatures viz. T = (313.15, 333.15, 353.15, and 373.15) K. From the experimental data, partial molar excess enthalpy values at infinite dilution were calculated for the experimental temperature range. The selectivity values for the separation of n-hexane/benzene, cyclohexane/benzene, and methanol/benzene mixtures were determined from the experimental infinite dilution activity coefficient values. These values were compared to those available in the literature for other ionic liquids and commercial solvents, so as to assess the feasibility of employing [3C 6C 14P][BF 4] in solvent-enhanced industrial separations.

Determination of Activity Coefficients at Infinite Dilution of 35 Solutes in the Ionic Liquid, 1-Butyl-3-methylimidazolium Tosylate, Using Gas−Liquid Chromatography

The activity coefficients at infinite dilution, γ13∞, for hydrocarbon solutes, alcohols, water, thiophene, ethers, and ketones in the ionic liquid 1-butyl-3-methylimidazolium tosylate (p-toluenesulfonate), [BMIM][TOS], have been determined by gas−liquid chromatography at temperatures T = (338.15, 348.15, 358.15, and 368.15) K. The selectivity values have been calculated at T = 338.15 K, and the results indicate that the ionic liquid [BMIM][TOS] should be considered as a solvent for separation of aromatic sulfur compounds from alkanes. The partial molar excess enthalpy values at infinite dilution ΔH1E∞, determined in this work, together with the values γ13∞ have been discussed in terms of intermolecular interactions and compared to results of related systems obtained earlier by us and from the literature.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate using gas–liquid chromatography at T = (313.15, 323.15, and 333.15) K

Activity coefficients at infinite dilution were determined for 24 solutes: n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes and alcohols in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate, [OMIM][PF 6], by gas–liquid chromatography at three different temperatures T = (313.15, 323.15, and 333.15) K. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental data over the same temperature range. Capacities and selectivities at infinite dilution for the systems hexane/benzene and methanol/benzene were determined from the experimental data and compared to the literature values for other ionic liquids, as well as for industrial molecular solvents. The influence of the cation and anion of the ionic liquid on the activity coefficient is discussed, as well as the usefulness of [OMIM][PF 6] in separating organic liquids.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate using gas–liquid chromatography at T = (313.15, 323.15, and 333.15) K

Activity coefficients at infinite dilution were determined for 24 solutes (n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes, and alcohols) in the ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate by gas-liquid chromatography at three different temperatures T = (313.15, 323.15, 333.15) K. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental results over the same temperature range. Selectivities and capacities at infinite dilution for the hexane/benzene and methanol/benzene separation problems were calculated from experimental infinite dilution activity coefficient values. The activity coefficients, enthalpies, selectivities, and capacities are discussed and compared to literature values for other ionic liquids, as well as industrial molecular solvents.

Activity coefficients at infinite dilution measurements for organic solutes in the ionic liquid N-butyl-4-methylpyridinium tosylate using GLC at T = (328.15, 333.15, 338.15, and 343.15) K

Activity coefficients at infinite dilution for 19 solutes: alkanes, cycloalkanes, alk-1-enes, alk-1-ynes, benzene and alcohols in the ionic liquid N-butyl-4-methylpyridinium tosylate ([BMPy][TOS]) were determined by gas–liquid chromatography at four temperatures T = (328.15, 333.15, 338.15, and 343.15) K. The partial molar excess enthalpy values at infinite dilution Δ H 1 E , ∞ were calculated from the experimental gamma infinity values obtained over the temperature range. The selectivity for the hexane/benzene and cyclohexane/benzene separations was calculated from the gamma infinity values and compared to the literature values for other ionic liquids, NMP and sulfolane.

Determination of Activity Coefficients at Infinite Dilution of Solutes in the Ionic Liquid, Trihexyltetradecylphosphonium Bis(trifluoromethylsulfonyl) Imide, Using Gas−Liquid Chromatography at T = (303.15, 308.15, 313.15, and 318.15) K

The activity coefficients at infinite dilution, γ13∞, for hydrocarbon solutes and some alcohols in the ionic liquid trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide [3C6C14P][Tf2N] have been determined by gas−liquid chromatography at temperatures T = (303.15, 308.15, 313.15, and 318.15) K. The selectivity values have been calculated at T = 308.15 K, and the results indicate that the ionic liquid [3C6C14P][Tf2N] should not be considered as a solvent for separation of alkanes and aromatics. The partial molar excess enthalpy values at infinite dilution ΔH1E∞, determined in this work, together with the values γ13∞ have been discussed in terms of intermolecular interactions and compared to results of related systems obtained from the literature.

Determination of Activity Coefficients at Infinite Dilution of Solutes in the Ionic Liquid 1-Butyl-3-methylimidazolium Octyl Sulfate Using Gas−Liquid Chromatography at a Temperature of 298.15 K, 313.15 K, or 328.15 K

The activity coefficients at infinite dilution, , for hydrocarbons and methanol solutes in the ionic liquid 1-butyl-3-methylimidazolium octyl sulfate, [BMIM][OcOSO3], have been determined by gas−liquid chromatography at temperatures of 298.15 K, 313.15 K, and 328.15 K. This work is part of our research focus on activity coefficients at infinite dilution, , in ionic liquids. The selectivity values have been calculated at T = 298.15 K, and the results indicate that the ionic liquid [BMIM][OcOSO3] should not be considered to be a solvent for the separation of alkanes and aromatics. The partial molar excess enthalpy values at infinite dilution have also been determined at temperature 298.15 K and have been discussed in terms of intermolecular interactions and packing effects. The results have been discussed in terms of measurements of for other ionic liquids taken from the recent literature.

Determination of Activity Coefficients at Infinite Dilution of Solutes in the Ionic Liquid 1-Hexyl-3-methylimidazolium Tetrafluoroborate Using Gas−Liquid Chromatography at the Temperatures 298.15 K and 323.15 K

The activity coefficients at infinite dilution, , for both polar and nonpolar solutes in an ionic liquid, 1-hexyl-3-methylimidazolium tetrafluoroborate ([HMIM+][BF4-]), have been determined by gas−liquid chromatography at T = (298.15 K and 323.15 K). This work is part of our research focus on ionic liquids. The selectivity values have been calculated at T = 298.15 K, and the results indicate that the ionic liquid, [HMIM+][BF4-], should be a good solvent for separation of benzene and alkanes. The partial molar excess enthalpy values at infinite dilution have also been determined at T = 298.15 K and have been discussed in terms of intermolecular interactions. The results have been discussed in terms of measurements of , using other ionic liquids, taken from the recent literature.