AbstractThe gas phase pyrolysis of 1,1,1,2‐tetrachloropropane was studied in a static system and seasoned vessel over the temperature range of 393.0–452.8°C and pressure range of 27.5–118.5 torr. The reaction is homogeneous, unimolecular, follows a first‐order rate law, and is not affected by the presence of the free radical inhibitor, toluene, or propene. The main dehydrochlorination products are 1,1,1‐trichloro‐2‐propene and 1,1,2‐trichloro‐1‐propene. The temperature dependence of the rate coefficient is given by the Arrhenius equation\documentclass{article}\pagestyle{empty}\begin{document}$$ \log {\rm }k_1 ({\rm s}^{{\rm - 1}}) = (11.98 \pm 0.34) - (205.1 \pm 4.6){\rm kJ/mol/2}{\rm .303}RT $$\end{document}The Arrhenius parameters of this reaction are apparently low. Consequently, in estimating the transition state ofA= 1013.5, the following expression is obtained\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm log }k_1 ({\rm s}^{ - {\rm 1}}) = 13.5 - 225.1{\rm kJ/mol/2}{\rm .303}RT $$\end{document}The partial rates and kinetic parameters for the parallel elimination products have been estimated and reported. The trichloromethyl substituent has been found to affect this elimination process through its electro