Selected ion flow tube studies of the gas-phase reactions of O ·−, O 2·− and OH − with a variety of brominated compounds

Abstract

The reactions of fourteen bromine-containing molecules, CH 3Br, CH 2Br 2, CHBrCl 2, CHBr 2Cl, C 2H 5Br, CH 2BrCH 2Br, CH 2BrCH 2Cl, CF 3Br, CF 2Br 2, CFBr 3, CBrClF 2, CFBr 2Cl, CCl 3Br and CF 2BrCF 2Br, with the anions O ·−, O 2 ·− and OH − in a 0.5 Torr helium buffer gas have been studied at 300 K using a selected ion flow tube. Reaction rate coefficients and branching ratios are presented. Several distinct reaction processes are observed among the large number of reactions studied, including nucleophilic attack, proton transfer, abstraction, and dissociative and non-dissociative electron transfer (within or out of a reaction complex). Of the forty-two bimolecular reactions, the rates of only two are significantly below the collisional rate and, for these two, competitive three-body processes are observed. Many of the reactions reported here have not previously been studied. This study, therefore, presents new data which provide additional insight into the reactions of anions with halogenated species.