Multivariate QSARs to model the hydroxyl radical rate constant for halogenated aliphatic hydrocarbons

Multivariate quantitative structure-activity relationships (QSARs) are applied to model the atmospheric persistence of halogenated aliphatic hydrocarbons. The objective is to forecast the rate of reaction between the haloalkanes and the hydroxyl radical in the gas phase. The QSARs are developed in the light of a recently proposed strategy for risk assessment of environmental chemicals, based on multivariate data analysis and statistical experimental design. The QSARs are calibrated using a training set consisting of ten chemicals and different sets of descriptors, namely empirical and qualitative indicator variables and quantum-chemical descriptors. The predictabilities of the QSARs are investigated by making predictions for 13 additional compounds for which experimental observations exist. Finally, the best obtained set of descriptors is used as a basis for making predictions for 35 non-tested haloalkanes.