Absolute determinations of the addition rate constants for the reactions of O( 3 P) atoms with halogenated propenes and butenes. A structure–activity relationship for the estimation of rate constants

The kinetics of the reactions of O( 3 P) atoms with CF 3 CHCH 2 , CF 3 CClCCl 2 , CF 3 CFCClCF 3 and CF 3 CClCClCF 3 were studied at 298 K using a discharge flow tube system. This is the first absolute kinetic study of these reactions. The overall rate constants based on the measured afterglow reactions were (3.4±0.4) × 10 −14 , (3.3±0.6) × 10 −14 , (1.3±0.3) × 10 −14 and (1.9±0.4) × 10 −14  cm 3 molecule −1  s −1 , respectively. The experiments were carried out under pseudo‐first‐order conditions with [O( 3 P)] 0 ≪ [alkene] 0 . The effect of substituent atoms or groups on the reactivity was analyzed. A simple method, using a structure–activity relationship based on the structure of the alkene, was applied for the first time to the reactions of O( 3 P) with haloalkenes. It is shown that this approach is useful in obtaining an initial estimate of unknown rate constants for reactions of O( 3 P) with alkenes. Copyright © 2004 John Wiley & Sons, Ltd.