Quantitative structure-property relationship (QSPR) models are developed to predict the logarithm of infinite dilution activity coefficient of hydrocarbons, oxygen containing organic compounds and halogenated hydrocarbons in water at 298.15 K. The description of the molecular structure in terms of quantum-connectivity descriptors allows to obtain more simple QSPR models because of the quantum-chemical and topological information coded in this type of descriptors. The models developed in this paper have fewer descriptors and better statistics than other models reported in literature. The current models allow a more transparent physical interpretation of the phenomenon in terms of intermolecular interactions which occur in solution and which explain the respective deviations from ideality.

A Quantitative Structure-Property Relationship (QSPR) model for the prediction of surface tension of organic compounds was derived from a data set of 320 chemicals including N, O, F, Cl, Br, and/or S atoms and covering a range of about 14-45 dyn cm-1. The model, only involving six molecular descriptors obtained solely from the chemical structures, yielded an r2 of 0.96. Its predictive capability was estimated from an external test set containing 55 structures not considered in the training set (r2 = 0.94). It was shown that the selected molecular descriptors presented a physical meaning corresponding to the different intermolecular interactions occurring in the bulk solution. The model is applicable to a wider variety of compounds, includes less parameters and correlates better than other QSPR models reported in literature.

No abstract