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

ABSTRACT

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.

KEYWORDS:

• Ionic liquid solvents
• partition coefficients
• solute transfer processes
• Abraham model correlations

Acknowledgements

Bihan Jiang and Melissa Horton thank the University of North Texas’s Texas Academy of Math and Science (TAMS) program for a summer research award.

Disclosure statement

No potential conflict of interest was reported by the authors.