Infinite Dilution Of Organic Solutes Research Articles

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.

Activity Coefficients at Infinite Dilution of Organic Solutes in 1-Butyl-3-methylimidazolium Nitrate Using Gas−Liquid Chromatography

Activity coefficients at infinite dilution of 21 organic solutes in the ionic liquid 1-butyl-3-methylimidazolium nitrate ([BMIM][NO3]) have been determined using gas−liquid chromatography over a temperature range of (303.15 to 363.15) K with the ionic liquid as the stationary phase. The partial molar excess enthalpies at infinite dilution and the solubility parameters of ionic liquid were determined for the solutes from the temperature dependence of the experimental activity coefficient at infinite dilution values.

Activity Coefficients at Infinite Dilution of Organic Solutes in 1-Decyl-3-methylimidazolium Tetrafluoroborate Using Gas−Liquid Chromatography

Activity Coefficients at Infinite Dilution of Organic Solutes in 1-Decyl-3-methylimidazolium Tetrafluoroborate Using Gas−Liquid Chromatography

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, methyl(trioctyl)ammonium thiosalicylate, [N1888][TS] by gas–liquid chromatography at T = (303.15, 313.15, and 323.15) K

In this work, activity coefficients at infinite dilution ( γ 13 ∞ ) have been obtained for 19 polar and non-polar organic solutes in the form of n-alkanes, cycloalkanes, 1-alkenes, 1-alkynes, aromatic compounds, and ketones in the ionic liquid methyl(trioctyl)ammonium thiosalicylate by gas–liquid chromatography at three different temperatures, i.e. T = (303.15, 313.15, and 323.15) K. Two columns with different phase loadings of the ionic liquid in the stationary phase (25% and 30%) were employed to obtain γ 13 ∞ values at each temperature investigated. Partial molar excess enthalpies at infinite dilution ( Δ H 1 E, ∞ ) were calculated for each of the solutes from the temperature dependency of the γ 13 ∞ values for the temperature range in this study. Selectivity values at infinite dilution ( S ij ∞ ) were computed from the γ 13 ∞ values to screen the potential candidacy of the ionic liquid for the separation of n-hexane/benzene mixtures. The results from this study have been compared to those available for several other classes of ionic liquids and commercial solvents employed in solvent-enhanced industrial separation processes.

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.

Measurements of Activity Coefficients at Infinite Dilution for Organic Solutes and Water in the Ionic Liquid 1-Butyl-1-methylpiperidinium Thiocyanate

The activity coefficients at infinite dilution (γ13∞) for 33 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water in the ionic liquid, 1-butyl-1-methylpiperidinium thiocyanate ([BMPIP][SCN]), were determined by gas−liquid chromatography over the temperature range (318.15 to 358.15) 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 heptane/benzene, cyclohexane/benzene, and heptane/thiophene separation problems were calculated from the γ13∞ and compared to the literature values for other ionic liquids with thiocyanate-based anion or with a butyl-methyl-substituted cation.

Physicochemical Properties and Activity Coefficients at Infinite Dilution for Organic Solutes and Water in the Ionic Liquid 1-Decyl-3-methylimidazolium Tetracyanoborate

The activity coefficients at infinite dilution γ(13)(∞) and gas−liquid partition coefficients K(L) for 43 solutes—alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, carboxylic acids, thiophene, ethers, ketones, and water—in the ionic liquid 1-decyl-3-methylimidazolium tetracyanoborate ([dmim][TCB]) were determined by gas−liquid chromatography at temperatures from 318.15 to 378.15 K. The partial molar excess Gibbs energies ΔG(1)(E,∞), enthalpies ΔH(1)(E,∞), and entropies ΔS(1)(E,∞) at infinite dilution were calculated from the experimental γ(13)(∞) values obtained over the temperature range. Additionally, the densities for investigated ionic liquid over the temperature range were determined. The selectivities for the aliphatic/aromatic hydrocarbon separation problem were calculated from γ(13)(∞) and compared to the literature values for N-methyl-2-pyrrolidinone (NMP) and sulfolane. It was found that the investigated [dmim][TCB] ionic liquid shows much higher capacity than NMP and sulfolane and selectivity on the same level as NMP and lower than that for sulfolane for the separation of aliphatic hydrocarbons from aromatic hydrocarbons.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate

Infinite dilution activity coefficients γ 1 ∞ and gas–liquid partition coefficients K L of 30 selected hydrocarbons, alcohols, ketones, ethers, esters, haloalkanes, nitrogen- and sulphur-containing compounds in the ionic liquid (IL) 1-ethyl-3-methylimidazolium methanesulfonate [EMIM][MeSO 3] were determined by gas–liquid chromatography at five temperatures in the range from 318.15 to 353.15 K. Relative contribution of adsorption at gas–liquid interphase to the overall solute retention, as examined by varying sample size and IL loading in the column, was found negligible. Partial molar excess enthalpies and entropies at infinite dilution were derived from the temperature dependence of the γ 1 ∞ values. The linear free energy relationship (LFER) solvation model was used to correlate successfully the K L values. The LFER correlation parameters and excess thermodynamic functions were analyzed to disclose molecular interactions operating between the IL and the individual solutes. Comparison to [EMIM][NO 3] studied previously revealed [MeSO 3] − anion to have still greater hydrogen bond basicity than that found for [NO 3] −. In addition, similarly to [EMIM][NO 3], promising potential of [EMIM][MeSO 3] for applications in solvent-aided separation processes was identified, the selectivities of [EMIM][MeSO 3] for separation of aromatic hydrocarbons and thiophene from saturated hydrocarbons ranking among the highest ever observed with ILs or molecular solvents.

Prediction of activity coefficients at infinite dilution for organic solutes in ionic liquids by artificial neural network

To our knowledge, this work illustrates for the first time the ability of artificial neural network (ANN) to predict activity coefficients at infinite dilution for organic solutes in ionic liquids (ILs). Activity coefficient at infinite dilution ( γ ∞) is a useful parameter which can be used for the selection of effective solvent in the separation processes. Using a multi-layer feed-forward network with Levenberg–Marquardt optimization algorithm, the resulting ANN model generated activity coefficient at infinite dilution data over a temperature range of 298 to 363 K. The unavailable input data concerning softness ( S) of organic compounds (solutes) and dipole moment ( μ) of ionic liquids were calculated using GAMESS suites of quantum chemistry programs. The resulting ANN model and its validation are based on the investigation of up to 24 structurally different organic compounds (alkanes, alkenes, alkynes, cycloalkanes, aromatics, and alcohols) in 16 common imidazolium-based ionic liquids, at different temperatures within the range of 298 to 363 K ( i.e. a total number of 914 γ Solute ∞ for each IL data point). The results show a satisfactory agreement between the predicted ANN and experimental data, where, the root mean square error (RMSE) and the determination coefficient ( R 2) of the designed neural network were found to be 0.103, 0.996 for training data and 0.128, 0.994 for testing data, respectively.

Activity coefficients at infinite dilution of organic solutes in N-alkylpyridinium bis(trifluoromethylsulfonyl)imide ([C nPY][NTf 2], n = 2, 4, 5) using gas–liquid chromatography

The activity coefficients at infinite dilution, γ i ∞ for both polar and non-polar solutes in the ionic liquids N-alkylpyridinium bis(trifluoromethylsulfonyl)imide ([C n PY][NTf 2], n = 2, 4, 5) have been determined by gas–liquid chromatography using the ionic liquid as the stationary phase. The measurements were carried out at the temperatures from (303 to 353) K. The partial molar excess enthalpies at infinite dilution H i E, ∞ of the solutes in the ionic liquids were also derived from the temperature dependence of the γ i ∞ values. The values of the selectivity for the hexane/benzene and cyclohexane/benzene separation problems were calculated from experimental infinite dilution activity coefficient values and compared to the other ionic liquids, taken from the recent literatures.

Measurements of activity coefficients at infinite dilution of organic solutes and water in 1-propyl-1-methylpiperidinium bis{(trifluoromethyl)sulfonyl}imide ionic liquid using g.l.c.

Activity coefficients at infinite dilution ( γ 13 ∞ ) of 38 different solutes (including alkanes, cyclohydrocarbons, alkenes, alkynes, benzene, alkylbenzenes, alcohols, water, thiophene, THF, MTBE, ethers, acetone, and n-ketones) in the ionic liquid 1-propyl-1-methylpiperidinium bis{(trifluoromethyl)sulfonyl}imide have been determined by using the g.l.c. method and have been reported over the temperature range from (308.15 to 358.15) K. The partial molar excess enthalpies of mixing at infinite dilution have been determined based on temperature dependence of γ 13 ∞ and discussed in terms of the intermolecular interactions. Selectivity and capacity at infinite dilution has been also calculated for chosen separation processes in systems ( n-hexane + benzene) and (cyclohexane + benzene) to evaluate if the studied ionic liquid is capable to be a good entrainer for these processes, e.g. in the liquid–liquid extraction. The results obtained are much better than many other ionic liquids with bis{(trifluoromethyl)sulfonyl}imide-based anion. However, the results are worse than for the thiocyanate-based ionic liquids.

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate [EMIM][TCB] using gas–liquid chromatography

The activity coefficients at infinite dilution, γ i ∞ , for both polar and non-polar solutes in the ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate [EMIM][TCB] have been determined by gas–liquid chromatography at the temperatures from (303 to 343) K. The partial molar excess enthalpies at infinite dilution H i E, ∞ of the solutes in the ionic liquid were also calculated from the temperature dependence of the γ i ∞ values. The selectivity for the hexane/benzene and cyclohexane/benzene separation problems was calculated from experimental infinite dilution activity coefficient values and compared to the other ionic liquids, taken from the recent literature.

Activity Coefficients at Infinite Dilution of Organic Solutes in 1-Ethyl-3-methylimidazolium Tris(pentafluoroethyl)trifluorophosphate [EMIM][FAP] Using Gas−Liquid Chromatography

The activity coefficients at infinite dilution, γi∞, for both polar and nonpolar solutes in the ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([EMIM][FAP]) have been determined by gas−liquid chromatography using the ionic liquid as the stationary phase. The measurements were carried out in the temperature range of (313 to 364) K. The partial molar excess enthalpies at infinite dilution HiE,∞ of the solutes in the ionic liquid were also derived from the temperature dependence of the γi∞ values.

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 of Organic Solutes in the Ionic Liquid 1-Ethyl-3-methyl-imidazolium Nitrate

Infinite dilution activity coefficients gamma(1)(infinity) and gas-liquid partition coefficients K(L) of 30 selected hydrocarbons, alcohols, ketones, ethers, esters, haloalkanes, nitrogen- and sulfur-containing compounds in the ionic liquid (IL) 1-ethyl-3-methylimidazolium nitrate [EMIM][NO(3)] were determined by gas-liquid chromatography at five temperatures in the range from 318.15 to 353.15 K. Relative contribution of adsorption at gas-liquid interphase to the overall solute retention, as examined by varying sample size and IL loading in the column, was found negligible. Partial molar excess enthalpies and entropies at infinite dilution were derived from the temperature dependence of the gamma(1)(infinity) values. The linear free energy relationship (LFER) solvation model was used to correlate successfully the KL values. The LFER correlation parameters and excess thermodynamic functions were analyzed to disclose molecular interactions operating between the IL and the individual solutes. In addition, the promising potential of [EMIM][NO(3)] for applications in solvent-aided separation processes was identified, the selectivities of [EMIM][NO(3)] for separation of aromatic hydrocarbons and thiophene from saturated hydrocarbons ranking among the highest ever observed with ILs or molecular solvents.

Activity Coefficients at Infinite Dilution of Organic Solutes in 1-Ethyl-3-methylimidazolium Tetrafluoroborate Using Gas−Liquid Chromatography

The activity coefficients at infinite dilution, γi∞, for 25 organic solutes, alkanes, alkenes, alkyl benzenes, acetonitrile, acetone, 1,4-dioxane, tetrahydrofuran, ethyl acetate, and chloromethanes, in the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) have been measured by the gas−liquid chromatographic method at temperatures from (303.15 to 363.15) K. The partial molar excess enthalpies at infinite dilution, HiE,∞, of the solutes in the ionic liquid were also derived from the temperature dependence of the γi∞ values.

Determination of activity coefficients at infinite dilution of organic solutes in the ionic liquid, tributylmethylphosphonium methylsulphate by gas–liquid chromatography

Activity coefficients at infinite dilution, γ i ∞ , have been determined for organic solutes in the phosphonium-based ionic liquid, tributylmethylphosphonium methylsulphate at T = 308.15 K, 318.15 K and 328.15 K. The experimental activity coefficient data presented are the first to be reported for this ionic liquid, through the use of the technique of steady-state gas–liquid chromatography. The organic solutes that were investigated were normal alkanes (pentane, hexane, heptane and octane), alkenes (1-hexene, 1-heptene and 1-octene), alkynes (1-hexyne, 1-heptyne and 1-octyne), cycloalkanes (cyclopentane, cyclohexane and cycloheptane) and benzene. The partial molar excess enthalpies at infinite dilution, H i E , ∞ , were also determined for the solutes from the temperature dependency of the γ i ∞ values. The γ i ∞ data obtained for tributylmethylphosphonium methylsulphate in this investigation have been compared to those obtained for other ionic liquids available in literature; most notably that of trihexyl(tetradecyl)-phosphonium tris(pentafluoroethyl) trifluorophosphate. This comparison allows for an assessment of the potential for the use of different ionic liquids as solvents in industrial solvent-enhanced separation processes such as extractive distillation.

Determination of activity coefficients at infinite dilution of organic solutes in the ionic liquid, trihexyl(tetradecyl)-phosphonium tris(pentafluoroethyl) trifluorophosphate, by gas–liquid chromatography

Activity coefficients at infinite dilution, γ i ∞ , have been determined for polar and non-polar organic solutes in the high molecular weight ionic liquid, trihexyl(tetradecyl)-phosphonium tris(pentafluoroethyl) trifluorophosphate at T = 308.15, 318.15 and 328.15 K. The experimental activity coefficient data presented are the first to be reported for the phosphonium-based ionic liquid. For the measurement of γ i ∞ , the technique of steady-state gas–liquid chromatography has been employed. The organic solutes that were investigated were normal alkanes (pentane, hexane, heptane and octane), alkenes (1-hexene, 1-heptene and 1-octene), alkynes (1-hexyne, 1-heptyne and 1-octyne), cycloalkanes (cyclopentane, cyclohexane and cycloheptane), alcohols (methanol, ethanol and propanol) and benzene. The partial molar excess enthalpies at infinite dilution, H i E , ∞ , were also determined for the solutes from the temperature dependency of the γ i ∞ values. The γ i ∞ data obtained for trihexyl(tetradecyl)-phosphonium tris(pentafluoroethyl) trifluorophosphate in this investigation have been compared to that obtained for other ionic liquids available in literature and the potential for the use of ionic liquids as solvents in industrial solvent-enhanced separation processes such as extractive distillation has been discussed.