Model Performances Evaluated for Infinite Dilution Activity Coefficients Prediction at 298.15 K

The infinite dilution activity coefficient (γi∞) is often
applied to characterize solvent−solute interactions, and, when
accurately predicted, it can also serve as an early-stage solvent
selection tool. Ample data are available on the use of a variety of
models, which complicates decision making on which model to
apply and when to apply it. A comparative study was performed for
eight predictive models at 298.15 K, including the Hildebrand
parameter and the Hansen solubility parameters. Also, three group
contribution methods based on UNIFAC, COSMO-RS, the
Abraham model, and the MOSCED model were evaluated. Overall,
the MOSCED model and the Abraham model are most accurate for
molecular solvents and ionic liquids, respectively, with average
relative deviations of 16.2% ± 1.35% and 65.1% ± 4.50%.
Therefore, cautious decision making based on predicted γi
∞ in ionic liquids should always be done, because of the expected
significant deviations. A MOSCED model for ionic liquids could be a potential approach for higher accuracy.