Temperature-dependent kinetics for the ozonolysis of selected chlorinated alkenes in the gas phase

The ozonolysis of olefinic species is an important tropospheric process impacting on climate and human health. However, few studies have investigated these reactions as a function of temperature and even less information is available upon the effects of alkene heteroatomic substitution on the Arrhenius parameters. The electron-withdrawing capacity of substituents about the olefinic bond strongly influences the rate of alkene ozonolysis. To understand better the effect of these substitutions, the temperature-dependence of a series of ozone-chloroalkene reactions is investigated. Experiments were conducted in the EXTreme RAnge (EXTRA) chamber, over the range of 292-409 K and 760 Torr. The experimentally determined rate coefficients were fitted using an Arrhenius-type analysis to yield the following activation energies: 30.80 ± 0.79, 23.18 ± 0.59, 65.2 ± 2.8, 116.9 ± 5.6, 29.5 ± 1.8, and 18.67 ± 0.96 kJ mol-1 and preexponential A-factors 1.22 +0.39-0.29×10-15, 9.3+6.7 -5.4×10-16, 1.6+2.5 -1.0×10-10, 6+22-3.9× 10-4, 1.7+1.6-0.8×10-14, and 4.2+1.9-1.3× 10-15 cm3 molecule-1 s-1 for cis-1,2-dichloroethene, trans-1,2-dichloroethene, trichloroethene, tetrachloroethene, 2-chloropropene, and 3-chloro-1-butene, respectively. © 2010 Wiley Periodicals, Inc.