Impact of critical point restriction on the calculation of surface tension of organic acids using group contribution models

Abstract

This manuscript reports the calculation of surface tension of organic acids using new group contribution models. These models were obtained from the Jasper equation and the van der Waals principle of corresponding states. A special analysis was performed to determine the impact of incorporating the critical point restriction on the performance of tested group contribution models. This restriction was incorporated via a penalty term on the objective function used in the group contribution determination, and using the reduced temperature as the input model variable. A total of 885 experimental surface tension data points for 78 organic acids (including aliphatic, aromatic, dicarboxylic, and polyfunctional acids) were used to compare the performance of these group contribution models. The results showed that tested models calculated the surface tension of polyfunctional and aliphatic organic acids with modeling errors lower than 5%. However, the calculation of surface tension of aromatic and dicarboxylic acids was challenging for all tested models. The incorporation of critical point restriction of surface tension as a penalty term in the data processing stage did not improve the performance of tested group contribution models. Group contribution models that used the reduced temperature as an input variable showed the best performance for the calculation of the surface tension of these organic compounds.