Comparison of theoretical methods for assessing the heat of formation of C1 and C2 chlorofluorocarbons and hydrochlorofluorocarbons

The heat of formation of a number of key C1 and C2 chlorofluorocarbons and hydrochlorofluorocarbons have been calculated by G3, G3MP2, G3MP2B3 and G3B3 methods. Based on the results of the atomization approach, it was found that the errors are approximately dependent upon the number of C–F or C–Cl bonds. Moreover, the bond additive correction (BAC) procedure and isodesmic reactions approach improved the accuracy and decreased these system errors significantly. The extended comparison between the BAC procedure and isodesmic reaction approaches had been made; the latter yielded the best results and showed broader applicability.

Deviations of calculated heat of formation from experimental data for the C2 CFCs and HCFCs in which the deviations are approximately dependent upon the number of C–F or C–Cl bonds.Figure optionsDownload as PowerPoint slide