Accurate pre-calculation of limiting activity coefficients by COSMO-RS with molecular-class based parameterization

The COSMO-RS method allows mixed-phase thermodynamic parameters to be calculated from quantum-chemically determined surface screening charge-density distributions. For this method we shall present and discuss a parameterization for alkanes and olefins in alcohols, which are important classes of molecules in industrial application. As we were able to demonstrate, the accuracy of predicting from a specialized parameterization can be significantly better than that from a universal parameterization. Furthermore, we critically compared the method with the UNIFAC(Do) group contribution method.

► A substance-class specific COSMO-RS parameterization is presented for the first time. ► A comparison of the error distributions of the COSMO-RS and group contribution methods is made. ► The accuracy of the molecular-class specific COSMO-RS parameterization equals that of UNIFAC(Do). ► New potential is opened up for the COSMO-RS method in industrial applications. ► Specialized parameterizations are possible for all classes, including those not describable using group contribution methods.