AbstractThe unimolecularity of the thermal dehydrogenation of cyclopentene has been confirmed using the technique of very low‐pressure pyrolysis (VLPP). Application of RRKM theory shows that the experimental unimolecular rate constants obtained over the temperature range of 942°–1152°K are consistent with the high‐pressure Arrhenius parameters given by\documentclass{article}\pagestyle{empty}\begin{document}$$ \log (k/\sec ^{-1}) = 13.35 - 61/\theta $$\end{document}where θ = 2.303RTkcal/mol. These parameters are in good agreement with static and shock tube studies. No firm evidence could be found for any side reactions or reversibility under the experimental conditi