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

Abstract 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.