Solute Distribution Ratio Research Articles

Capacity of ionic liquids [EMim][NTf 2] and [EMpy][NTf 2] for extraction of toluene from mixtures with alkanes: Comparative study of the effect of the cation

The ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMim][NTf 2] and 1-ethyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, [EMpy][NTf 2] have been studied as solvents for the extraction of toluene from mixtures with alkanes (heptane or cyclohexane). The liquid–liquid equilibria of ternary systems {heptane or cyclohexane + toluene + [EMim][NTf 2] or [EMpy][NTf 2]} and {heptane + cyclohexane + [EMim][NTf 2] or [EMpy][NTf 2]} at 298.15 K and atmospheric pressure were determined. The solute distribution ratio and selectivity derived from the tie-lines were used to determine if these ionic liquids can be used as extraction solvents. The tie-lines were satisfactorily correlated by means of the thermodynamic NRTL model for ternary systems with [EMpy][NTf 2] and with NRTL and UNIQUAC models for the ternary systems with [EMim][NTf 2].

Hexyl dimethylpyridinium ionic liquids for desulfurization of fuels. Effect of the position of the alkyl side chains

In this work, the desulfurization ability of the 1-hexyl-2,4-dimethylpyridinium bis(trifluoromethylsulfonyl)imide ionic liquid, [h 2,4mmpy][NTf 2], has been compared with that of 1-hexyl-3,5-dimethylpyridinium bis(trifluoromethylsulfonyl)imide, [h 3,5mmpy][NTf 2]. With this aim, liquid–liquid equilibrium data have been obtained for the [h 2,4mmpy][NTf 2] + thiophene + toluene, [h 2,4mmpy][NTf 2] + thiophene + hexane and [h 2,4mmpy][NTf 2] + pyridine + hexane ternary systems at 298.15 K and atmospheric pressure. The obtained data have been adequately correlated using the UNIQUAC and NRTL models. The suitability of both ionic liquids as solvents for extractive desulfurization has been evaluated in terms of solute distribution ratio and selectivity.

Extraction of Benzene from Aliphatic Compounds Using Commercial Ionic Liquids as Solvents: Study of the Liquid–Liquid Equilibrium at T = 298.15 K

In this paper, the liquid extraction of benzene from aliphatic compounds (heptane, octane, cyclooctane, and methylcyclohexane) using commercial ionic liquids (ILs; 1-propyl-3-methylimidazolium bis{trifluoromethylsulfonyl}imide, [PMim][NTf2], and 1-butyl-3-methylimidazolium bis{trifluoromethylsulfonyl}imide, [BMim][NTf2]) as solvents was studied. The liquid–liquid equilibrium (LLE) data for five ternary systems (aliphatic compound + benzene + IL) are reported at T = 298.15 K and atmospheric pressure. The cloud point method was used to determine the solubility curves, and the tie-line compositions were obtained by density measurements. From the experimental LLE data, the selectivity and the solute distribution ratio were calculated. The degree of consistency of the tie-lines was tested using the Othmer–Tobias equation, and the experimental LLE data were correlated using nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) thermodynamic models. Moreover, a systematic study about the influence of the size of the aliphatic and IL on the aromatic extraction was carried out.

Study of [EMim][ESO 4] ionic liquid as solvent in the liquid–liquid extraction of xylenes from their mixtures with hexane

The aim of this work is to determine if the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate is a good solvent for the separation of xylenes and hexane by liquid extraction. With this purpose, liquid–liquid equilibrium (LLE) data for the ternary systems {hexane + o-xylene, or m-xylene, or p-xylene + 1-ethyl-3-methylimidazolium ethylsulfate} were determined at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio, derived from the experimental equilibrium data, were calculated and used to determine if this ionic liquid can be used as a potential solvent for the extraction of xylenes from their mixtures with hexane. The experimental LLE data for the ternary systems were correlated using the NRTL and UNIQUAC models.

Deterpenation of Citrus Essential Oil by Liquid−Liquid Extraction with 1-Alkyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)amide Ionic Liquids

Three 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ionic liquids, namely, those with ethyl-, hexyl-, or decyl- as the alkyl substituent chain, were evaluated as potential solvents for the deterpenation of citrus essential oil by liquid−liquid extraction. The citrus essential oil was simulated as a mixture of the terpene limonene and the oxyterpene linalool. The liquid−liquid equilibrium data for the ternary systems formed by limonene, linalool, and each of the ionic liquids selected were experimentally determined at 298.15 K. The suitability of the ionic liquids as solvents for the proposed process was evaluated by means of solute distribution ratio and selectivity values. The influence of the alkyl side chain in the imidazolium cation of the ionic liquids on the liquid−liquid equilibrium data was analyzed. By comparison with data previously reported in the literature for analogous systems, the influence of the ionic liquid anion on the proposed separation was also analyzed. The experimen...

Application of [EMim][ESO4] ionic liquid as solvent in the extraction of toluene from cycloalkanes: Study of liquid–liquid equilibria at T = 298.15 K

In this paper, the separation of toluene from cycloalkanes by liquid extraction using the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate, [EMim][ESO4], as solvent was studied. Liquid–liquid equilibrium (LLE) data for ternary systems {cyclohexane, or cyclooctane, or methylcyclohexane+toluene+[EMim][ESO4]} were determined at T=298.15K and atmospheric pressure. Selectivity and solute distribution ratio, derived from the tie-lines, were used to determine the ability of this ionic liquid as solvent for the separation of toluene from its mixtures with cycloalkanes. The degree of consistency of the tie-lines was tested using the Othmer–Tobias equation, and the experimental LLE data were correlated using the non-random two-liquid (NRTL) and the UNIversal QUAsi-Chemical (UNIQUAC) models.

Synthesis and characterization of new polysubstituted pyridinium-based ionic liquids: application as solvents on desulfurization of fuel oils

The production of transportation fuels which have a very low content of sulfur has became one of the priority challenges for the oil industry worldwide, due to by strict new regulatory requirements. Ionic liquids (ILs) have been proposed as suitable and promising solvents for this purpose due to their excellent qualities as solvents. In this work a series of ten new ILs derived from pyridinium cation substituted with different alkyl chains have been synthesized from 2-alkyl-3,5-dimethylpyridines. The starting materials were prepared by selective metalation of 2,3,5-trimethylpyridine, which allowed the introduction of different alkyl groups in pyridine position 2 with high yields. To test the ILs sulfur-removal capacity, liquid–liquid equilibrium (LLE) data for ternary systems (heptane + thiophene + IL) were determined at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio, calculated from tie-lines, were used to evaluate whether these new ILs could be used as solvents for the extraction of thiophene from heptane. Finally, the experimental LLE data were correlated with the NRLT thermodynamic model.

(Liquid + liquid) equilibrium data for the ternary systems (cycloalkane + ethylbenzene + 1-ethyl-3-methylimidazolim ethylsulfate) at T = 298.15 K and atmospheric pressure

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 = 298.15 K 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.

Separation of toluene from cyclic hydrocarbons using 1-butyl-3-methylimidazolium methylsulfate ionic liquid at T = 298.15 K and atmospheric pressure

In this paper the extraction of toluene from cyclic hydrocarbons (cyclohexane, or methylcyclohexane, or cyclooctane, or cyclohexene) was analyzed by liquid extraction with 1-butyl-3-methylimidazolium methylsulfate ionic liquid, [BMim][MSO 4], as solvent. The experimental (liquid + liquid) equilibrium (LLE) data were determined at T = 298.15 K and atmospheric pressure. Solubility curves were obtained by the cloud point method and tie-line compositions were determined by density measurement. An analysis of the influence of different cyclic hydrocarbons on the extraction was performed. The effectiveness of the extraction of toluene from cyclic hydrocarbons was evaluated by means of the solute distribution ratio and selectivity values. The degree of consistency of the experimental LLE data was ascertained using the Othmer–Tobias and Hand equations. The experimental data for the (liquid + liquid) equilibria of the ternary systems were correlated with the Non-Random Two-Liquid (NRTL) and UNIversal QUAsi-Chemical (UNIQUAC) thermodynamic models.

Distribution ratio, distribution constant and partition coefficient. Countercurrent chromatography retention of benzoic acid

There is some confusion in chromatography between terms such as solute distribution ratio, distribution constant and partition coefficient. These terms are very precisely defined in the field of liquid–liquid systems and liquid–liquid extraction as well as in the field of chromatography with sometimes conflicting definitions. Countercurrent chromatography (CCC) is a chromatographic technique in which the stationary phase is a support-free liquid. Since the mobile phase is also liquid, biphasic liquid systems are used. This work focuses on the exact meaning of the terms since there are consequences on experimental results. The retention volumes of solutes in CCC are linearly related to their distribution ratios. The partition coefficient that should be termed (IUPAC recommendation) distribution constant is linked to a single definite species. Using benzoic acid that can dimerize in heptane and ionize in aqueous phase and an 18mL hydrodynamic CCC column, the role and relationships between parameters and the consequences on experimental peak position and shape are discussed. If the heptane/water distribution constant (marginally accepted to be called partition coefficient) of benzoic acid is 0.2 at 20°C and can be tabulated in books, its CCC measured distribution ratio or distribution coefficient can change between zero (basic aqueous mobile phase) and more than 25 (acidic aqueous mobile phase and elevated concentration). Benzoic acid distribution ratio and partition coefficient coincide only when both dimerization and ionization are quenched, i.e. at very low concentration and pH 2. It is possible to quench dimerization adding butanol in the heptane/water system. However, butanol additions also affect the partition coefficient of benzoic acid greatly by increasing it.

Extraction of toluene from aliphatic compounds using an ionic liquid as solvent: Influence of the alkane on the (liquid + liquid) equilibrium

In this paper, the feasibility of using 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid, [EMim][ESO 4], as solvent for the extraction of toluene from aliphatic compounds (hexane, heptane, octane, or nonane) was analyzed. (Liquid + liquid) equilibrium (LLE) data for the ternary systems {alkane (1) + toluene (2) + [EMim][ESO 4] (3)} were measured at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio were calculated from the experimental LLE data, and the obtained values were compared to those previously reported using other ionic liquids and sulfolane. The degree of consistency of the experimental LLE data was ascertained using the Othmer–Tobias equation. Finally, the experimental LLE data were satisfactorily correlated with NRTL and UNIQUAC models.

Liquid−Liquid Equilibria of the Ternary Systems of Alkane + Aromatic + 1-Ethylpyridinium Ethylsulfate Ionic Liquid at T = (283.15 and 298.15) K

In this work, the ionic liquid [EPy][EtSO4] was tested as a solvent for the separation of benzene from alkanes. The liquid−liquid equilibrium (LLE) data for the ternary mixtures of octane (1) or nonane (1) + benzene (2) + 1-ethylpyridinium ethylsulfate ([EPy][EtSO4]) (3) at T = (283.15 and 298.15) K and atmospheric pressure were experimentally determined. The cloud-point method was used to determine the solubility curve, and the tie-line compositions were obtained by density measurements. The effectiveness of the extraction of benzene from an alkane was evaluated by means of the calculation of the solute distribution ratio and selectivity values. The consistency of tie-line data was ascertained by applying the Othmer−Tobias and Hand equations. A correlation of the experimental tie lines was conducted through the use of the nonrandom two-liquid (NRTL) equation, which provides a good correlation of the experimental data. The results show that [EPy][EtSO4] can be used as an alternative solvent in liquid extraction processes for the removal of benzene from its mixtures with alkanes.

Liquid–liquid equilibrium and interfacial tension of the ternary system heptane + thiophene + 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

The liquid–liquid equilibrium (LLE) of the ternary system comprising heptane, thiophene and the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C 2mim][NTf 2]) was determined at 25 °C and atmospheric pressure, for preliminary evaluation of the potential of this ionic liquid as solvent for the desulfurisation of transportation fuels. Classical parameters such as solute distribution ratio and selectivity were calculated from the LLE data and subsequently analysed. The LLE data were also correlated by means of the ‘Non-Random Two-Liquid’ (NRTL) equation. Besides the LLE, another critical property for the design of extraction processes, namely the interfacial tension, was determined in parallel, throughout the immiscibility domain of the ternary system. For the first time, the LLE and the interfacial tension of a ternary system involving an ionic liquid are jointly reported.

Liquid Extraction of Benzene from Its Mixtures Using 1-Ethyl-3-methylimidazolium Ethylsulfate as a Solvent

In this work, the separation of benzene from cycloalkanes (cyclohexane, methylcyclohexane, and cyclooctane) was investigated by liquid extraction using the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate, [EMim][ESO4]. The liquid−liquid equilibrium (LLE) data were measured for the ternary systems formed by cycloalkane, benzene, and [EMim][ESO4] at 298.15 K and atmospheric pressure. The cloud point method was used to determine the solubility curve data, and the tie-line compositions were obtained by density measurements. The selectivity, the percent removal of aromatic, and the solute distribution ratio were calculated from the experimental LLE data. Selectivity and solute distribution ratio values were compared to those previously reported with other ionic liquids and sulfolane. Moreover, the influence of the size of the cycloalkane on the aromatic extraction was analyzed. The reliability of the experimental LLE data was tested using the Othmer−Tobias equation, and the NRTL and UNIQUAC models were used to correlate the experimental LLE data.

Separation of Benzene from Linear Alkanes (C6−C9) Using 1-Ethyl-3-Methylimidazolium Ethylsulfate at T = 298.15 K

In this work, the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate, [EMim][ESO4], is used to separate benzene from alkanes (hexane, heptane, octane, nonane) by solvent extraction through the study of the liquid−liquid equilibria of the ternary systems at T = 298.15 K and atmospheric pressure. The selectivity, solute distribution ratio, and percent removal of the aromatic, calculated from the tie-line data, were used to determine whether this ionic liquid is a good solvent for the extraction of benzene from alkane compounds. The consistency of the tie-line data was ascertained by applying the Othmer−Tobias equation, and the experimental results for the ternary systems were correlated with the nonrandom two-liquid (NRTL) and the universal quasi-chemical (UNIQUAC) models.

Application of [EMpy][ESO 4] ionic liquid as solvent for the liquid extraction of xylenes from hexane

Liquid–liquid equilibrium (LLE) data for the ternary systems {hexane + o-xylene + 1-ethyl-3-methylpyridinium ethylsulfate}, {hexane + p-xylene + 1-ethyl-3-methylpyridinium ethylsulfate}, and {hexane + m-xylene + 1-ethyl-3-methylpyridinium ethylsulfate} were determined at T = 298.15 K and atmospheric pressure. Selectivity, percent removal of aromatic, and solute distribution ratio, derived from the experimental equilibrium data, were used to determine if this ionic liquid can be used as a potential extracting solvent for the separation of xylenes from hexane. The consistency of tie-line data was ascertained by applying the Othmer–Tobias equation. The phase diagrams for the ternary systems are shown, and the tie-lines correlated with the NRTL model have been compared with the experimental data.

Liquid–liquid equilibria for ternary systems of {cyclohexane + aromatic compounds + 1-ethyl-3-methylpyridinium ethylsulfate}

Liquid–liquid equilibrium (LLE) data for the ternary systems {cyclohexane + benzene + 1-ethyl-3-methylpyridinium ethylsulfate}, {cyclohexane + toluene + 1-ethyl-3-methylpyridinium ethylsulfate}, and {cyclohexane + ethylbenzene + 1-ethyl-3-methylpyridinium ethylsulfate} were determined at T = 298.15 K and atmospheric pressure. Selectivity, percent removal of aromatic, and solute distribution ratio, derived from the equilibrium data, were used to determine if this ionic liquid can be used as a potential solvent for the separation of aromatic compounds from cyclohexane. The phase diagrams for the ternary systems are shown, and the tie-lines correlated with NRTL model have been compared with the experimental data.

Essential oil deterpenation by solvent extraction using 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate ionic liquid

Taking into account that heat application can have undesirable effects in essential oil properties, liquid extraction comes up as a promising process instead of distillation for citrus oil deterpenation. In this work the suitability of using the ionic liquid 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate as a solvent for the extraction of linalool from citrus essential oil (which has been simulated as a mixture of limonene and linalool) has been analyzed. Liquid–liquid equilibrium data at three different temperatures (298.15 K, 308.15 K and 318.15 K) have been reported and successfully correlated using NRTL model. The best results were achieved using α = 0.1 for the systems at 298.15 K and 308.15 K and α = 0.2 at 318.15 K. The solute distribution ratio has showed values close to one and high values of selectivity have been achieved.

Separation of toluene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at T=298.15K and atmospheric pressure

Abstract In this paper, the separation of toluene from aliphatic hydrocarbons (heptane, or octane, or nonane) was analyzed by solvent extraction with 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid, [EMpy][ESO4]. Liquid−liquid equilibrium (LLE) data for the ternary systems {heptane (1) + toluene (2) + [EMpy][ESO4] (3)}, {octane (1) + toluene (2) + [EMpy][ESO4] (3)}, and {nonane (1) + toluene (2) + [EMpy][ESO4] (3)} were obtained by measurements at T = 298.15 K and atmospheric pressure. The selectivity, % removal of aromatic, and solute distribution ratio, obtained from experimental equilibrium results, were used to determine the ability of [EMpy][ESO4] as a solvent. The degree of consistency of the experimental LLE values was ascertained using the Othmer–Tobias and Hand equations. The experimental results for the ternary systems were correlated with the NRTL model. Finally, the results obtained were compared with other ionic liquids and other solvents.

An ionic liquid proposed as solvent in aromatic hydrocarbon separation by liquid extraction

AbstractLiquid–liquid extraction is the most common method for extraction of aromatics from their mixtures with aliphatic hydrocarbons. An ionic liquid (IL) 1‐butyl‐1‐methylpyrrolidinium bis (trifluoromethylsulfonyl) imide [BMpyr][NTf2] was tested as solvent for this separation. The liquid–liquid equilibria (LLE) of the ternary mixtures heptane + benzene, or toluene, or ethylbenzene + [BMpyr][NTf2] were carried out at 298.15 K. The solvent ability of the IL was evaluated in terms of solute distribution ratio and selectivity. The results were compared with those previously reported for the extraction of aromatics from its mixtures with heptane by using ILs. The conventional process using sulfolane as solvent was discussed. The experimental LLE data were correlated by non‐random two liquid equation. A proposal of extraction process with this IL as solvent is simulated by conventional software and the results are shown. © 2009 American Institute of Chemical Engineers AIChE J, 2010