Temperature dependences of the reactions of O(3P) atoms with selected chlorofluoroethenes between 298 and 359 K

✍ Scribed by Mariano A. Teruel; Pablo M. Cometto; Raúl A. Taccone; Silvia I. Lane

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 117 KB
• Volume: 37
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20126

✦ Synopsis

Abstract

The rate constants for the gas‐phase reactions of ground‐state oxygen atoms with CF~2~CFCl (1), (E/Z)‐CFClCFCl (2), CFClCH~2~ (3), and (E/Z)‐CFHCHCl (4) have been measured directly using a discharge flow tube coupled to a chemiluminescence detection system. The experiments were carried out under pseudo‐first‐order conditions with [O^3^P)]~0~ ≪ [ethene]~0~. The temperature dependences of the reactions were studied for the first time in the range 298–359 K. The proposed Arrhenius expressions (in units of cm^3^ molecule^−1^ s^−1^) were k~1~ = (1.07 ± 0.32) × 10^−11^ exp{−(8000±1600)/RT}, k~2~ = (0.56 ± 0.10) × 10^−11^ exp{−(8700±500)/RT}, k~3~ = (4.23 ± 1.25) × 10^−11^ exp{−(12,700 ± 800)/RT}, and k~4~ = (1.13 ± 0.62) × 10^−11^ exp{−(10,500 ± 1500)/RT}. All the rate coefficients display a positive temperature dependence, which highlights the importance of the irreversibility of the addition mechanism for these reactions. Halogen substitution in the ethene is discussed in terms of reactivity with O(^3^P). © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 763–769, 2005