Laser Photolysis - LIF Kinetic Studies of the Reactions of CH₃O and CH₂CHO with O₂ between 300 and 500 K

Rate constants for the reactions (1) CH₃O (methoxy) + O₂ and (2) CH₂CHO (vinoxy) + O₂ have been determined between 300 and 500 K using a combined laser photolysis/laser induced fluorescence technique. Whereas reaction (1) is purely bimolecular with k₁ = (5.5 ± 2.0) 10⁻¹⁴ exp(−1000 K/T) cm³s, reaction (2) appears to be a recombination process. For p = 130 mbar (M = He) we find k₂ = (2.7 ± 1.5) 10⁻¹⁴ exp(668 K/T) cm³s, corresponding to a T^−1.8 negative temperature dependence.