Data have been compiled from the published literature on the partition coefficients of solutes and vapors into anhydrous sulfolane. The logarithms of the water-to-sulfolane partition coefficients, log P, and gas-to-sulfolane partition coefficients, log K, were correlated with the Abraham solvation parameter model. The derived correlations described the observed log P and log K values for solutes dissolved in sulfolane to within average standard deviations of 0.14 log units or less. The log P correlation was extended to include the partition of ions by inclusion of a cation-solvent and an anion-solvent term.
Experimental data have been compiled from the published literature on the partition coefficients of solutes and vapors into o-xylene, m-xylene and p-xylene at 298 K. The logarithms of the water-to-xylene partition coefficients, log P, and gas-to-xylene partition coefficients, log K, were correlated with the Abraham solvation parameter model. The derived mathematical expressions described the observed log P and log K data for the three xylene isomers to within average deviations of 0.14 log units or less.
Key words and phrasesPartition coefficients, xylene solvents, Abraham model correlations ________________________________________________________________________ *To whom correspondence should be addressed. (E-mail: acree@unt.edu) 2
IntroductionLiquid-liquid extraction affords a convenient experimental means for separating synthesized organic materials from reaction solvent media, and for pre-concentrating chemicals in unknown liquid samples prior to quantitative analyses. Extraction methods are based on solute partitioning in a biphasic liquid system containing two or more solvents having limited mutual solubility. Molecular interactions between the dissolved solute(s) and surrounding extraction solvents determine the solute recovery factor and separation efficiency. Considerable attention has been given in recent years to developing methods for selecting the best biphasic partitioning system to achieve a desired chemical separation.In many previous studies [1-8], we have shown that two general linear free energy Abraham model correlations, equations 1 and 2, can be used to mathematically describe the transfer of neutral solutes from water to organic solvents and from the gas phase to organic solvents log P = c p + e p ·E + s p ·S + a p ·A + b p ·B + v p ·Vlog K = c k + e k ·E + s k ·S + a k ·A + bk·B + l k ·LThe dependent variables in eqns. 1 and 2 are the logarithm of the water-to-organic solvent partition coefficient, log P, and the logarithm of the gas-to-organic solvent partition coefficient, log K, for a series of solutes. The independent variables, or solute descriptors, are properties of the neutral solutes as follows: [9,10] E is the solute excess molar refraction in cm 3 mol -1 /10, S is the solute dipolarity/polarizability, A is the overall solute hydrogen bond acidity, B is the overall solute hydrogen bond basicity, V is McGowan's characteristic molecular volume in cm 3 mol -1 /100 and L is the logarithm of the gas to hexadecane partition coefficient measured at 298 K.
Experimental data have been compiled from the published chemical and engineering literature pertaining to the infinite dilution activity coefficients, gas solubilities and chromatographic retention factors for solutes dissolved in ionic liquid (IL) solvents. Included in the compilation are chromatographic retention factors for forty-five solutes on a 1-butyl-1-methylpyrrolidinium tricyanomethanide ionic liquid gas-liquid chromatographic stationary phase. The published experimental data were converted to gas-to-IL and water-to-IL partition coefficients, and correlated with the ion-specific equation coefficient version of the Abraham general solvation 2 model. Ion-specific equation coefficients were calculated for 40 different cations and 16 different anions. The calculated ion-specific equation coefficients describe the experimental gas-to-IL and water-to-IL partition coefficient data to within 0.123 and 0.149 log units, respectively.
Data have been assembled from the published literature on the enthalpies of solvation for 91 organic vapors and gaseous solutes in 2-propanol, for 73 gaseous compounds in 2-butanol, for 85 gaseous compounds in 2-methyl-1-propanol and for 128 gaseous compounds in ethanol. It is shown that an Abraham solvation equation with five descriptors can be used to correlate the experimental solvation enthalpies to within standard deviations of 2.24 kJ/mole, 1.99 kJ/mole, 1.73 kJ/mole and 2.54 kJ/mole for 2-propanol, 2-butanol, 2-methyl-1-propanol and ethanol, respectively. The derived correlations provide very accurate mathematical descriptions of the measured enthalpy of solvation data at 298 K, which in the case of ethanol span a range of 136 kJ/mole. Division of the experimental values into a training set and a test set shows that there is no bias in predictions, and that the predictive capability of the correlations is better than 3.5 kJ/mole.
Experimental solubilities are reported for 3,4-dichlorobenzoic acid dissolved in methyl butyrate, and in 16 alcohol, 5 alkyl acetate, 5 alkoxyalcohol and 6 ether solvents. Solubilities were also measured in nine binary aqueous-ethanol solvent mixtures at 298.15 K. The measured solubility data were correlated with the Abraham solvation parameter model. Mathematical expressions based on the Abraham model predicted the observed molar solubilities to within 0.12 log units.
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