US EPA

7744551 

Journal Article 

Kinetics of the gas-phase reactions of Cl atom with selected C-2-C-5 unsaturated hydrocarbons at 283 < T < 323 K 

Coquet, S; Ariya, PA 

2000 

Yes 

International Journal of Chemical Kinetics
ISSN: 0538-8066
EISSN: 1097-4601 

32 

8 

478-484 

English 

10.1002/1097-4601(2000)32:8<478::AID-KIN5>3.3.CO;2-J 

WOS:000087992600005 

The reaction of Cl atoms with a series of C2-C5 unsaturated hydrocarbons has been investigated at atmospheric pressure of 760 Torr over the temperature range 283-323 K in air and N2 diluents. The decay of the hydrocarbons was followed using a gas chromatograph with a flame ionization detector (GC-FID), and the kinetic constants were determined using a relative rate technique with n-hexane as a reference compound. The Cl atoms were generated by UV photolysis (λ≥300 nm) of Cl2 molecules. The following absolute rate constants (in units of 10-11 cm3 molecule-1 s-1, with errors representing ±2σ) for the reaction at 295±2 K have been derived from the relative rate constants combined to the value 34.5×10-11 cm3 molecule-1 s-1 for the Cl+n-hexane reaction: ethene (9.3±0.6), propyne (22.1±0.3), propene (27.6±0.6), 1-butene (35.2±0.7), and 1-pentene (48.3±0.8). The temperature dependence of the reactions can be expressed as simple Arrhenius expressions (in units of 10-11 cm3 molecule-1 s-1): kethene = (0.39±0.22)×10-11 exp((226±42)/T), kpropyne = (4.1±2.5)×10-11 exp((118±45)/T), kpropene = (1.6±1.8)×10-11 exp((203±79)/T), k1-butene = (1.1±1.3)×10-11 exp((245±90)/T), and kl-pentene = (4.0±2.2)×10-11 exp((423±68)/T). The applicability of our results to tropospheric chemistry is discussed.