Kinetics of the pyrolyses of endo‐ and exo‐5‐methylbicyclo (2.2.2) oct‐2‐ene in the gas phase

The pyrolyses of endo‐ and exo‐5‐methylbicyclo (2.2.2) oct‐2‐ene (endo‐ and exo‐MBO) have been studied between 608 and 679°K at pressures between 7 and 37 torr. These reactions correspond to parallel first‐order eliminations of propene and ethylene: equation image The rate constants (in sec−1) for endo‐MBO are given by and those for exo‐MBO by Reaction mechanisms involving diradicals are shown to be compatible with the experimental results. The heats of formation and the entropies of endo and exo‐MBO are estimated.