Method for Estimating Activity Coefficients of Target Components in Poorly Specified Mixtures

Mixtures that contain a known target component but are otherwise poorly specified are important in many fields. Previously, the activity of the target component, which is needed, e.g., to design separation processes, could not be predicted in such mixtures. A method was developed to solve this problem. It combines a thermodynamic group contribution method for the activity coefficient with NMR spectroscopy, which is used for estimating the nature and amount of the different chemical groups in the mixture. The knowledge of the component speciation of the mixture is not required. Test cases that are inspired by bioprocess engineering applications show that the new method gives surprisingly good results.