Crossed beam reaction of the phenyl radical, (C 6H 5, X 2A′) with molecular oxygen [formula omitted]: Observation of the phenoxy radical, (C 6H 5O, X 2A′)

Abstract

The chemical dynamics of the combustion-relevant reaction of phenyl radicals with molecular oxygen were investigated in a crossed beam reaction at a collision energy of 107 kJ mol −1. Under these conditions, the formation of the phenoxy radical (C 6H 5O) plus ground state atomic oxygen was observed; no atomic hydrogen exchange pathway was opened. The reaction dynamics of the phenoxy radical channel were found to be direct, involved a stripping-like reaction mechanism, and were initiated by a radical–radical recombination of phenyl plus molecular oxygen forming a short lived phenylperoxy radical (C 6H 5O 2). The latter decomposed to the phenoxy radical plus atomic oxygen; the overall reaction was exoergic by about 38 ± 15 kJ mol −1.