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

Quantitative structure-property relationship (QSPR) and group contribu tion-additivity (GCA) models have been developed for predicting the no rmal boiling points of diverse fluorocarbons and fluorocarbon-hydrocar bon diblock compounds. The models are based on experimental boiling po ints and intrinsic molecular properties (i.e., dynamic polarizability and isopotential surfaces)of 68 uniquely structured fluorocarbons. The molecular properties were obtained from quantum mechanical calculatio ns utilizing the PM3 Hamiltonian. The QSPR and GCA models have an aver age error of 5 and 3%, respectively. The error reduction in the GCA mo del is due to effective distribution of the contributory propagated er rors. A wide range of fluorocarbons was examined, and 21 group contrib utions were delineated. These include such groups and heteroatoms as R (F), R(H), C=O, NH2, OH, C, N, O, Cl, Br, and I.