QSPR AND GCA MODELS FOR PREDICTING THE NORMAL BOILING POINTS OF FLUOROCARBONS

Quantitative structure-property relationship (QSPR) and group contribution-additivity (GCA) models have been developed for predicting the normal boiling points of diverse fluorocarbons and fluorocarbon-hydrocarbon diblock compounds. The models are based on experimental boiling points and intrinsic molecular properties (i.e., dynamic polarizability and isopotential surfaces)of 68 uniquely structured fluorocarbons. The molecular properties were obtained from quantum mechanical calculations utilizing the PM3 Hamiltonian. The QSPR and GCA models have an average error of 5 and 3%, respectively. The error reduction in the GCA model is due to effective distribution of the contributory propagated errors. A wide range of fluorocarbons was examined, and 21 group contributions were delineated. These include such groups and heteroatoms as R(F), R(H), C=O, NH2, OH, C, N, O, Cl, Br, and I.