The kinetics and the mechanism of the thermal gas‐phase reaction between bis(trifluoromethyl)trioxide, CF 3 O 3 CF 3 and 1,1‐dichlorodifluoroethylene, CF 2 CCI 2

Abstract The thermal addition of CF 3 O 3 CF 3 (T) to CF 2 CCl 2 (E) has been investigated between 49.6 and 69.5°C. The initial pressure of CF 3 O 3 CF 3 was varied between 7 and 240 torr and that of CF 2 CCl 2 between 4 and 600 torr. Four products of formula CF 3 O (E) j OOCF 3 , where j = 1 → 4 are formed. The sum of the products Σ   i = 1 4CF 3 O (E) j OOCF 3 is equal to the amount of trioxide decomposed. The reaction is homogeneous. Its rate is not affected by the total pressure and the presence of inert gas. It is a free radical telomerization with four basic steps: thermal decomposition of CF 3 O 3 CF 3 into CF 3 O . and CF 3 O 2 . , chain initiation by addition of CF 3 O . to olefin incorporated in, and telomeric radicals termination. The consumption of alkene is well represented by the equation:\documentclass{article}\pagestyle{empty}\begin{document}$$ - d[E]/dt = k_1 [T]\left\{ {1 + \sum\limits_{j = 1}^3 {\prod\limits_{i = 1}^j {[1 + (k_{t_1 } k_1^{1/2} /k_{gi} } k_t^{1/2})([T]^{1/2} /[E])]^{ - 1} } } \right\} $$\end{document}where ( d [ E ]/ d [ T ]) =\documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document}is the mean chain length of telomerization.\documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document}varies from 1.45 at 1.5 torr of E to 3.3 at 400 torr of E . Above this pressure E has no influence on\documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document} . The estimated value of the constant for the addition of telomeric radicals to alkene is:\documentclass{article}\pagestyle{empty}\begin{document}$$ k_g \simeq 8.6 \pm 6.0 \times 10^4 \exp ( - 2300 \pm 200{\rm col mol}^{{\rm - 1}} /RT){\rm M}^{{\rm - 1}} {\rm s}^{{\rm - 1}} $$\end{document}