Kinetics and mechanism of the gas-phase reaction of the CIO radical with alkanes

Abstract

The products in the early stages of the reaction of ∼20 torr. chlorine monoxide with ∼200 torr. propane and isobutane in the gas phase at 38–110° are hypochlorous acid and alkyl chlorides. From the yields of the isomeric chlorides, the ratio of rate constants for the reaction ClO·+ RH → HOCl + R· are k_prim : k_sec : k_tert= 1 : 22 : 71 at 95°. The activation energy for abstraction from a primary bond is 1·4 kcal. mole^–1 greater than abstraction from a secondary C–H bond. A chain mechanism has been proposed which gives good agreement between the observed and calculated overall rate of reaction.