trends in solvent impact on infinite dilution activity coefficients of solutes reviewed and visualized using an algorithm to support selection of solvents for greener fluid separations

The infinite dilution activity coefficient, gamma(infinity)(i), is a frequently used molecular descriptor to pre-select a solvent for various kinds of fluid separations. Unfortunately, information related to these coefficients is scattered throughout the open literature. Therefore, an open-source gamma(infinity)(i)-database containing 77.173 gamma(infinity)(i) data points over the temperature interval 243 K < T < 555.6 K for 268 solutes and 692 solvents is provided in the electronic supporting information of this work. Additionally, we performed an inter- and extrapolation data analysis algorithm using the Van 't Hoff equation to extend the gamma(infinity)(i) data points at 298.15 K. The gamma(infinity)(i) for five solutes (n-hexane, benzene, chloroform, acetone and ethanol) in a wide range of molecular solvents and ionic liquids (ILs) were compared. Various trends between the molecular solvent structure and the gamma(infinity)(i) are visualized, which allows for not only a pre-selection of solvents for targeted gamma(infinity)(i) but also visualizes the effect molecular modification of the solvent will have on the gamma(infinity)(i). Overall, the presented methodology is complementary to approaches using simulation software, and helps acquiring a detailed understanding of the effect of the solvent structure on the gamma(infinity)(i), which will facilitate solvent pre-selection in an early process design stage towards greener fluid separations.

Automated summary

This study provides an open-source database with a large number of γ∞(i) data points, and utilizes the Van 't Hoff equation for data analysis and extrapolation. The γ∞(i) for five solutes in different solvents were compared, visualizing trends between solvent structure and γ∞(i).