Rate Constants of the Reactions of O(3P) Atoms with Ethene and Propene over the Temperature Range 230–900 K

Abstract

ABSTRACTThe kinetics of the reactions of ethene and propene with triplet oxygen atoms have been studied over a wide temperature range, T = 230–900 K, using a low‐pressure (P = 1 Torr) flow tube reactor coupled with an electron impact ionization quadrupole mass spectrometer: O + C2H4 → products (1) and O + C3H6 → products (2). The rate constants of the title reactions were determined under pseudo–first‐order conditions, either monitoring the kinetics of O‐atom consumption in excess of alkene or alkene loss in excess of oxygen atoms. The temperature dependence of the rate constant of reaction (1), k1 = 8.64 × 10−17 T1.70 exp(–206/T) cm3 molecule−1 s−1 (uncertainty of 20%), was found to be in excellent agreement with multiple previous data that can be considered as a validation of the experimental approach. The measurements of the rate constant of the reaction of O atoms with propene, k2 = 3.65 × 10−18 T2.20 exp(455/T) cm3 molecule−1 s−1 (uncertainty of 20%), allowed to harmonize the results of previous low‐ and high‐temperature measurements and to recommend the expression for k2 in a wide temperature range, 200–1200 K.