Prediction of reaction rate constants of hydroxyl radical with chemicals in water

The rate constants (k(OH)) of the reactions between organic micropollutants with hydroxyl radical (center dot OH) in aqueous systems are an important parameter to evaluate the persistence of organic compounds in the environment. In this paper, a support vector machine (SVM) model based on five descriptors was built to predict the reaction rate constants (log K = (log k(OH))/M-W). The quantitative structure-activity relationship (QSAR) model of log K was obtained from a training set (600 compounds) and validated with a test set (395 compounds). The coefficients of determination R-2 of the training and test sets are 0.923 and 0.925, respectively. The results suggest that the SVM model developed in this work possesses satisfactory prediction ability. Practitioner points The rate constants of the reactions of organic micropollutants with center dot OH in aqueous systems were investigated. SVM model was established for the reaction rate constants (log K = (log k(OH))/M-W). Only five molecular descriptors were used to predict 995 log K. A large data set was used for the test set (395 compounds).