Ion-specific equation coefficient version of the Abraham model for ionic liquid solvents: determination of coefficients for tributylethylphosphonium, 1-butyl-1-methylmorpholinium, 1-allyl-3-methylimidazolium and octyltriethylammonium cations

Gas-to-ionic liquid partition coefficient data have been assembled from the published chemical literature for solutes dissolved in 1-allyl-3-methylimidazolium dicyanamide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulphonyl)imide, octyltriethylammonium bis(trifluomethyl-sulphonyl)imide, tributylethylphosphonium diethylphosphate and 1-butyl-1-methylmorpholinium tricyanomethanide. The published experimental data were converted to water-to-ionic liquid partition coefficients using standard thermodynamic relationships. Both sets of partition coefficients were correlated with the Abraham solvation parameter model. The derived Abraham model correlations described the observed partition coefficient data to within 0.13 log units. Cation-specific equation coefficients were calculated for each of the cations present in the five ionic liquid solvents studied. The calculated cation-specific equation coefficients can be combined with previously reported ion-specific equation coefficients for 19 different anions to yield Abraham model correlations for predicting the partitioning the behaviour of solutes in 76 different anhydrous ionic liquid solvents.     

Abraham model ion-specific equation coefficients for the 1-butyl-2,3-dimethyimidazolium and 4-cyano-1-butylpyridinium cations calculated from measured gas-to-liquid partition coefficient data

Partition coefficient and gas solubility data have been assembled from the published chemical and engineering literature for solutes dissolved in anhydrous 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, and 4-cyano-1-butylpyrridinium bis(trifluoromethylsulfonyl)imide. More than 60 experimental data points were gathered for each IL solvent. The compiled experimental data were used to derive Abraham model correlations for describing the solute transfer properties into the three anhydrous IL solvents from both the gas phase and water. The derived mathematical correlations described the observed solute transfer properties, expressed as the logarithm of the water-to-IL partition coefficient and logarithm of the gas-to-IL solvent partition coefficient, to within standard deviations of 0.125 log units (or less). Abraham model ion-specific equation coefficients are also calculated for the 1-butyl-2,3-dimethylimidazolium and 4-cyano-1-butylpyridinium cations.     

Correlations for describing gas-to-ionic liquid partitioning at 323 K based on ion-specific equation coefficient and group contribution versions of the Abraham model

Chromatographic retention measurements were measured for a wide range of solutes on 1-methyl-3-ethylimidazolium tris(pentafluoroethyl)trifluorophosphate, ([MEIm]⁺[FAP]⁻), and 1-(3-hydroxypropyl)pyridinium tris(pentafluoroethyl)trifluorophosphate, ([1-PrOHPy]⁺[FAP]⁻), stationary phases at 323 K. The measured retention factors were combined with published infinite dilution activity coefficient, gas solubility data and retention factor data to yield gas-to-anhydrous ionic liquid (IL) partition coefficients at 323 K for 2349 different solute-IL combinations. The compiled partition coefficient data were analyzed using the ion-specific equation coefficient and the functional group contribution versions of the Abraham solvation parameter model. Ion-specific equation coefficients were calculated for 25 cations and 14 anions. In addition, values were calculated for 14 cation functional groups and 14 anions. The calculated ion-specific equation coefficients and calculated functional group values described the experimental 323 K partition coefficient data to within standard deviations of 0.10 and 0.13 log units, respectively.     

Infinite dilution activity coefficients and gas-to-liquid partition coefficients of organic solutes dissolved in 1-sec-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and in 1-tert-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

Inverse gas chromatography was used to measure infinite dilution activity coefficients and gas-to-liquid partition coefficients for 48 organic solute probes in either 1-sec-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-tert-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide in the temperature range from 323.15 to 373.15 K. Partial molar excess enthalpies of solution were calculated from the variation of the infinite dilution activity coefficients with temperature. Abraham model correlations were also derived from the experimental partition coefficient data. The derived Abraham model correlations describe the observed partition coefficients to within 0.11 log units.     

Linear free energy relationship correlations for the solubilising characterisation of room temperature ionic liquids containing 1-hexyloxymethyl-3-methylimidazolium and 1,3-dihexyloxymethylimidazolium cations

Gas-to-room temperature ionic liquid (RTIL) partition coefficients have been compiled from the published literature for solutes dissolved in 1-hexyloxymethyl-3-methylimidazolium bis(trifluoromethylsulphonyl)imide, {[HxomMIm]⁺[(Tf)₂N]^?}, and in 1,3-dihexyloxymethylimidazolium bis(trifluoromethylsulphonyl)imide, {[(Hxom)₂Im]⁺[(Tf)₂N]^?}. These partition coefficients are converted into water-to-RTIL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients are analysed using the Abraham model with cation-specific and anion-specific equation coefficients. The equation coefficients are reported for the 1-hexyloxymethyl-3-methylimidazolium and 1,3-dihexyloxymethylimidazolium cations. The calculated cation coefficients can be combined with our previously determined nine sets of anion-specific equation coefficients to yield expressions capable of predicting the partition coefficients of solutes in 18 different RTILs.     

Development of Abraham model IL-specific correlations for N-triethyl(octyl)ammonium bis(fluorosulfonyl)imide and 1-butyl-3-methylpyrrolidinium bis(fluorosulfonyl)imide

ABSTRACT

Abraham model correlations are derived for describing gas-to-ionic liquid and water-to-ionic liquid partition coefficients from published experimental data for solutes dissolved in both N-triethyl(octyl)ammonium bis(fluorosulfonyl)imide and 1-butyl-3-methyl-pyrrolidinium bis(fluorosulfonyl)imide. Derived Abraham model correlations describe the observed partition coefficient data to within 0.13 log units. As part of the current study the existing equation coefficients for the N-triethyl(octyl)ammonium cation were updated and reported for the first time were equation coefficients for the bis(trifluorosulfonyl)imide anion.     

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 1-ethyl-3-methylimidazolium trifluoroacetate

The activity coefficients at infinite dilution, gamma13(infinity) for 29 solutes, alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols and water in the ionic liquid 1-ethyl-3-methylimidazolium trifluoroacetate ([EMIM][TFA]), were determined by gas-liquid chromatography at temperatures from 298.15-368.15 K. The partial molar excess enthalpies at infinite dilution DeltaH1(E,infinity) values were calculated from the experimental gamma13(infinity) values obtained over the temperature range. The selectivities for the hexane/benzene and cyclohexane/benzene separation were calculated from gamma13(infinity) and compared to the literature values for other ionic liquids, NMP and sulfolane.     

Partition coefficients of organic compounds in new imidazolium based ionic liquids using inverse gas chromatography

Partition coefficients of organic compounds in four ionic liquids: 1-ethanol-3-methylimidazolium tetrafluoroborate, 1-ethanol-3-methylimidazolium hexafluorophosphate, 1,3-dimethylimidazolium dimethylphosphate and 1-ethyl-3-methylimidazolium diethylphosphate were measured using inverse gas chromatography from 303.3 to 332.55 K. The influence of gas–liquid and gas–solid interfacial adsorption of different solutes on ionic liquids was also studied. Most of the polar solutes were retained largely by partition while light hydrocarbons were retained predominantly by interfacial adsorption on the ionic liquids studied in this work. The solvation characteristics of the ionic liquids were evaluated using the Abraham solvation parameter model.     

Development of Abraham model expressions for predicting the enthalpies of solvation of solutes dissolved in acetic acid

Experimental data have been compiled from the published chemical and engineering literature on the enthalpies of solvation for 92 different inorganic gases and organic vapours in acetic acid. The compiled data are used to derive mathematical correlations based on the Abraham solvation parameter model. The derived expressions describe the experimental solvation enthalpies in acetic acid to within a standard deviation (SD) of 2.2 kJ mol^?1. Principal Component Analysis (PCA) on the five equation coefficients from a derived Abraham model correlation shows that acetic acid does not resemble hydroxylic solvents in terms of enthalpic interactions, but is more akin to moderately polar solvents such as ethyl acetate or acetone.     

Determination of solute partition behavior with room-temperature ionic liquid based micellar gas-liquid chromatography stationary phases using the pseudophase model

The use of micelles in ionic liquid based gas-chromatography stationary phases was evaluated using equations derived for a "three-phase" model. This model allows the determination of all three partition coefficients involved in the system, and elucidates the micellar contribution to retention and selectivity. Four types of micellar-ionic liquid columns were examined in this study: 1-butyl-3-methylimidazolium chloride with sodium dodecylsulfate or dioctyl sulfosuccinate, and 1-butyl-3-methylimidazolium hexafluorophosphate with polyoxyethylene-100-stearyl ether or polyoxyethylene-23-lauryl ether. The partition coefficients were measured for a wide range of probe molecules capable of a variety of types and magnitudes of interactions. In general, most probe molecules preferentially partitioned to the micellar pseudophase over the bulk ionic liquid component of the stationary phase. Therefore, addition of surfactant to the stationary phase usually resulted in greater solute retention. It is also shown that the selectivity of the stationary phase is significantly altered by the presence of micelles, either by enhancing or lessening the separation. The effects of surfactant on the interaction parameters of the stationary phase are determined using the Abraham solvation parameter model. The addition of sodium dodecylsulfate and dioctyl sulfosuccinate to 1-butyl-3-methylimidazolium chloride stationary phases generally increased the phase's hydrogen bond basicity and increased the level of dispersion interaction. Polyoxyethylene-100-stearyl ether and polyoxyethylene-23-lauryl ether surfactants, however, enhanced the pi-pi/n-pi, polarizability/dipolarity, and hydrogen bond basicity interactions of 1-butyl-3-methylimidazolium hexafluorophosphate to a greater degree than the ionic surfactants with 1-butyl-3-methylimidazolium chloride. However, these nonionic surfactants appeared to hinder the ability of the stationary phase to interact with solutes via dispersion forces. Therefore, it is possible to effectively predict which analytes will be most highly retained by these micellar-ionic liquid stationary phases.     

Characterization of room-temperature ionic liquids by the Abraham model with cation-specific and anion-specific equation coefficients

Gas-to-RTIL (room-temperature ionic liquid) partition coefficients have been compiled for 592 different solute-RTIL combinations. These partition coefficients were converted into water-to-RTIL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analyzed using the Abraham solvation parameter model with cation-specific and anion-specific equation coefficients. The derived equations correlated the experimental gas-to-RTIL and water-to-RTIL partition coefficient data to within 0.10 and 0.14 log units, respectively. The 8 sets of calculated cation-specific equation coefficients and 4 sets of calculated anion-specific equation coefficients can be combined to yield expressions capable of predicting the partition coefficients of solutes in 32 different RTILs.     

Osmotic coefficients of aqueous solutions of four ionic liquids at T = (313.15 and 333.15) K

Measurements of osmotic coefficients of BmimCl (1-butyl-3-methylimidazolium chloride), HmimCl (1-hexyl-3-methylimidazolium chloride), MmimMeSO₄ (1,3-dimethylimidazolium methylsulfate), and BmimMeSO₄ (1-butyl-3-methylimidazolium methylsulfate) with water at T = (313.15 and 333.15) K are reported in this work. Vapour pressure and activity data of all the studied binary systems are obtained from experimental data. The osmotic coefficients data are correlated using the extended Pitzer model of Archer and the modified NRTL (MNRTL) model and standard deviations obtained with both models are given too. The parameters obtained with the extended Pitzer model of Archer are used to calculate the mean molal activity coefficients.     

A new diastereoselective intramolecular electroreductive coupling of unsaturated β-ketoesters and β-ketoamides in ionic liquids at a tin cathode

The diastereoselective intramolecular electroreductive coupling of several β-ketoesters and β-ketoamides has been accomplished at a tin cathode in ionic liquids and isopropanol (9:1). The ionic liquids used are 1-butyl-3-methylimidazolium bromide [BMIM]Br, 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM]BF₄, 1-methoxyethyl-3-methylimidazolium trifluoroacetate [MOEMIM]CF₃COO and 1-methoxyethyl-3-methylimidazolium mesylate [MOEMIM]Ms. This methodology offers a clean and green process for the synthesis of functionalized carbocycles in good yields with excellent stereochemical control at three stereogenic centres.     

Osmotic coefficients of binary mixtures of four ionic liquids with ethanol or water at T = (313.15 and 333.15) K

Measurements of osmotic coefficients of BmimCl (1-butyl-3-methylimidazolium chloride) and HmimCl (1-hexyl-3-methylimidazolium chloride) with ethanol and EmimEtSO₄ (1-ethyl-3-methylimidazolium ethylsulfate) and EmpyEtSO₄ (1-ethyl-3-methylpyridinium ethylsulfate) with water at T = (313.15 and 333.15) K are reported in this work. Vapour pressure and activity results of the studied binary systems are obtained from experimental measurements. The results for the osmotic coefficients are correlated using the extended Pitzer model modified by Archer and the modified NRTL (MNRTL) model. The standard deviations obtained with both models are also given. The parameters obtained with the extended Pitzer model of Archer are used to calculate the mean molal activity coefficients.     

Linear free energy relationship (LFER) correlations for the solubilising characterisation of room temperature ionic liquids containing triethylsulphonium and 1-butyl-1-methylpyrrolidinium cations

Gas-to-room temperature ionic liquid (RTIL) partition coefficients have been compiled from the published literature for solutes dissolved in triethylsulphonium bis(trifluoromethylsulphonyl)imide, {[E₃S]⁺[(Tf)₂N]^?}, and in 1-butyl-1-methylpyrrolidinium trifluoromethanesulphonate, {[BMPyr]⁺[Trif]^?}. These partition coefficients were converted into water-to-RTIL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analysed using the Abraham model with cation-specific and anion-specific equation coefficients. Equation coefficients are reported for the triethylsulphonium and 1-butyl-1-methylpyrrolidinium cations. The calculated cation coefficients can be combined with our previously determined eight sets of anion-specific equation coefficients to yield expressions capable of predicting the partition coefficients of solutes in 16 different RTILs.     

Osmotic and activity coefficients in the binary solutions of 1-butyl-3-methylimidazolium chloride and bromide in methanol or ethanol at T = 298.15 K from isopiestic measurements

Osmotic coefficients of the binary solutions of two room-temperature ionic liquids (1-butyl-3-methylimidazolium chloride and bromide) in methanol and ethanol have been measured at T = 298.15 K by the isopiestic method. The experimental osmotic coefficient data have been correlated using a forth-order polynomial in terms of (molality)^0.5, with both, ion interaction model of Pitzer and electrolyte non-random two liquid (e-NRTL) model of Chen. The values of vapor pressures of above-mentioned solutions have been calculated from the osmotic coefficients. The model parameters fitted to the experimental osmotic coefficients have been used for prediction of the mean ionic activity coefficients of those ionic liquids in methanol and ethanol.