Kinetics of C2H radical reactions with ethene, propene and 1-butene measured in a pulsed Laval nozzle apparatus at T=103 and 296 K

Low-temperature kinetics of the reactions of C2H radical with ethene (k1), propene (k2), and 1-butene (k3) are studied using a pulsed Laval nozzle supersonic expansion. The C2H decay profiles in the presence of both the alkene reactant and O2 are monitored by the CH(A2Δ) chemiluminescence tracer method. The rate constants k1, k2, and k3 are measured at T=103 K to be (1.4±0.4)×10−10, (2.4±0.6)×10−10, and (2.6±0.6)×10−10 cm3 molecule−1 s−1, respectively. Measurements at room temperature (296 K) and previous data suggest a slight negative temperature dependence for all three reactions.