Predicting PC-SAFT parameters based on COSMO-RS

To predict the size (m, sigma) and energy (epsilon) parameters of the perturbed-chain statistical associating fluid theory (PC-SAFT) based on the conductor-like screening model for realistic solvents (COSMO-RS), in this work, the PC-SAFT model parameters of 304 substances were reviewed and summarized, their COSMO-RS results linked to the size and energy were predicted, and the relationships between the PC-SAFT parameters and COSMO-RS results were obtained in 3 cases (Case 1: relationships based on n-alkanes, Case 2: category-specific relationships, Case 3: generic relationships for 138 substances). Case 2 (including Case 1) shows the lowest average absolute relative deviations (AARDs) of 7.63% (m), 3.05% (sigma), and 9.05% (epsilon), while Case 3 provides the prediction capacity with AARDs of 10.00% (m), 4.05% (sigma), and 13.21% (epsilon), which is better than those developed by others. Finally, the new PC-SAFT parameters were used to predict the densities and vapor pressures of 8 representative substances and compared with the results using the original PC-SAFT parameters, showing that the parameters in Case 3 can be used to reproduce densities and the parameters in Case 2 (including Case 1) can be used to reproduce both densities and vapor pressures.

Automated summary

In this study, the size and energy parameters of the PC-SAFT model were predicted based on the COSMO-RS results. The relationships between the PC-SAFT parameters and COSMO-RS results were obtained in three cases, with Case 2 showing the best prediction capacity. Furthermore, the new PC-SAFT parameters were used to predict the densities and vapor pressures of representative substances.