Predicting Henry's law constant and the effect of temperature on Henry's law constant

Air-water partitioning data for a wide range of organic chemicals are used to validate a three-variable quantitative structure-activity relationship (QSAR) model for Henry's law constant, H. The predictive ability of the basic model, developed from a training set of 180 chemicals, is now demonstrated on 105 new chemicals of similar molecular structure. This basic model is then extended to cover additional chemicals of diverse molecular features. The predictive ability of the final model is demonstrated on a new testing set of 70 chemicals featuring multiple structural components and polyfunctional groups. Spanning over 10 orders of magnitude, the log H values predicted by the QSAR model for 462 compounds are found to agree with the reported experimental values with r² > 0.95 at p = 0.0005. A new QSAR model for estimating H as a function of temperature, T, is also proposed. The predictive ability of this H-T model is demonstrated using experimental data for 18 chemicals over a temperature range of 10-55°C.