Infinite dilution activity coefficient from SMD calculations: accuracy and performance for predicting liquid-liquid equilibria.

Prediction of liquid-liquid phase equilibria is an important goal in the physical chemistry of solutions. Quantum chemistry methods, combined with a dielectric continuum description of the solvent, has received attention as a first principle approach. In this work, the performance of the continuum solvation model based on density (SMD) for prediction of γ∞ in binary liquid mixtures, using 46 values of γ∞, was evaluated. We found the mean uncertainty of RTln γ∞ to be 0.92 kcal mol-1. Based on the calculated γ∞ and the two parameters of the Redlich-Kister expansion, we calculated the liquid-liquid phase equilibria. Based on 26 values of solubility, an uncertainty of 0.66 was found in the logarithm of molar fraction of the smallest component in each phase. Our results suggest this approach can be used for fast and semi-quantitative prediction of phase behavior. More reliable predictions could be obtained with improvements in the SMD model. Graphical abstract Prediction of liquid-liquid phase equilibriaᅟ.