Rate Constant and Branching Ratio for the Reactions of the Ethyl Peroxy Radical with Itself and with the Ethoxy Radical

The self-reaction of the ethyl peroxy radical (C2H5O2) (1) has been studied using laser photolysis coupled to a selective time-resolved detection two different radicals by continuous-wave cavity ring-down spectroscopy (cw-CRDS) in near-infrared range: C2H5O2 was detected Ã-X̃ electronic transition at 7596 cm–1 and HO2 2ν1 vibrational overtone 6638.2 cm–1. Radicals were generated from pulsed 351 nm C2H6/Cl2 mixture presence O2. reaction can proceed via propagation channel, leading C2H5O (1a) or stable products (1b/1c). Because react subsequently with O2, HO2, which turn reacts rapidly C2H5O2, knowledge branching ratio is indispensable for retrieving rate constant. A strong disagreement exists about constant between recommendation IUPAC (Atkinson et al., Atmos. Chem. Phys. 2006, 3625) JPL (Publication 19-5, 2020) recent, more direct measurement (Noell J. 2010, 6983). found here be k1 = (1.0 ± 0.2) × 10–13 cm3 s–1 fraction channel being α (0.31 0.06), contradiction recommendations, but confirming most recent indicating that current this should revised. ethoxy (C2H5O) also involved mechanism, its extracted modeling. It k9 (7 1.5) 10–12 s–1, times slower than only available Noell al. 6983.