Temperature dependences of the reactions of O(3P) with chlorofluoroalkenes

M.A.TERUEL, P. M. COMETTO, M. B. BLANCO, R.A.TACCONE Y S.I.LANE

Leeds, UK

Conferencia; Faraday Discusión 130-Atmospheric Chemistry; 2005

As part of a systematic study of O(3P) atom reactivity , we report in this work absolute rate constants for the reactions of O(3P) with CFCl=CH2, (E/Z)-CFH=CClH, (E/Z)-CFCl=CHCl, CF3CCl=CCl2, CF3CF=CF2, CF3CF=CClCF3 and CF3CCl=CClCF3 measured in a  discharge flow tube apparatus coupled with a chemiluminescence detection system to monitor the O(3P) decay. The absolute rate coefficients as a function of temperature were measured in the temperature range of 295-359 K and the activation energies and preexponential factors calculated. As far as we know, this is the first systematic investigation, using an absolute technique, temperature dependent study of the reaction of O(3P) with all the alkenes above mentioned. There is only one measurement for the CF3CF=CF2 by Saunders and Heicklen  at two temperatures.  The present work was undertaken in order to augment the existing scant supply of kinetic information about the O(3P)-haloalkene reactions. We have also studied the temperature dependences of these reactions, in the hope that an improved understanding of the reaction mechanism might be forthcoming.