The gas-phase unimolecular thermal isomerization of pentachlorocyclopropane

Abstract

The gas-phase thermal isomerization of pentachlorocyclopropane to 1,1,3,3,3-pentachloropropene has been studied in the temperature range 440–490 K at pressures between 10 and 50 Torr. The reaction is of the first order and was unaffected by changes in surface:volume ratio or by the addition of cyclohexene. The rate constants log₁₀k/s^–1=(14·16 ± 0·23)–(39,963 ± 500)/4·576T(i) fit the Arrhenius equation (i). The reaction is interpreted as a unimolecular process taking place with chlorine-atom migration through a concerted transition state.