Decomposition of 1,1,2,2‐tetrafluorocyclopropane. Arrhenius parameters and their influence on the chemical activation results

The kinetics of the gas‐phase thermal decomposition of 1,1,2,2‐tetrafluorocyclopropane (TFC) to 1,1‐difluoroethylene and CF 2 was studied in the temperature range of 507.0‐577.0 K and with a total pressure of 200 to 300 torr of a 1:100 mixture of reactant and C 2 H 4 . Also at 557.0 K experiments were made at different total pressures, in the range 2–20 torr with neat TFC and between 20–300 torr with the C 2 H 4 /TFC mixture, confirming that the reaction is in the high pressure limit. The reaction is first‐order and the rate constants fit the following Arrhenius relationship:\documentclass{article}\pagestyle{empty}\begin{document}$$\log \,k/(s^{ - 1}) = (14.02 \pm 0.16) - (45,150 \pm 200)/4.576T$$\end{document} From this value of the activation energy, the data for the decomposition of chemically activated TFC were revised. The new results yield a minimum energy of the activated molecule of 98 ± 4 kcal/mol and ΔH   f ° (TFC) = −155.4 ± 7 kcal/mol, while an analysis of the kinetic data yields ΔH   f ° (TFC) = −159 ± 9 kcal/mol.