Gas-phase reactivity study of O(~3P) atoms with trans-CHCl=CHCl and CHCl=CCl_2 at 298 K:Comparison to reactions with some other substituted ethenes

摘要

Absolute rate coefficients for the gas-phase reactions of trans-dichioroethene and trichioroethene with O(3P) atoms have been measured at 298 K using a discharge flow tube coupled to a chemiluminescence detection system. The observed rate constant values are (2.2±0.4) X l0~(-13) and (1.4 ± 0.2) X l0X~(-13) cm~3 molecule~(-1) s~(-1), respectively. The experiments were carried out under pseudo-first-order conditions with [O(~3P)]_0[alkene]_0. These results are compared to those of 0 atom reactions with other chioroethenes and with different elec-trophiles, such as OH and NO_3. Different factors that affect the rate of addition to the double bond are considered. The rate constants for these reactions do not correlate in a simple manner with the experimental ionization potential, as is the case in the alkene and methyl-substituted alkene reactions.