Kinetic Studies of Diatomic Free Radicals Using Mass Spectrometry: Part 4.—The Br + OClO and BrO + ClO reactions

Abstract

In a kinetic study of the reaction of ground state Br 2P[fraction three-over-two] bromine atoms with chlorine dioxide, it has proved possible to determine not only the rate constant k–1a for the primary reaction, but also the rate constants k1a, k1b, for the various reactions of ClO with BrO radicals via different channels (1a) and (1b). The rate constants (cm3 molecule–1 s–1 at 298 K; error = 1.5σ) were as follows: [graphic omitted] The reaction kinetics were studied in a flow system using collision-free sampling of free radicals and stable molecules to a mass spectrometer. The thermochemistry and reaction kinetics of the XO + XO reactions (X = Cl, Br) are discussed. The ClO + ClO, BrO + BrO and BrO + ClO reactions are all thought to occur via related free radical channels, XO + XO ⇌ X + XOO. In addition, the ClO + ClO and BrO + ClO reactions occur through a similar and parallel channel, XO + XO ⇌ X + OXO.