Kinetic study of the reactions of Br2 with OH and OD

The kinetics of the reactions OH + Br2 → HOBr + Br (1) and OD + Br2 → DOBr + Br (3) have been studied in the temperature range 230–360 K and at total pressure of 1 Torr of helium using the discharge-flow mass spectrometric method. The following Arrhenius expressions were obtained either from the kinetics of product formation (HOBr, DOBr) in excess of Br2 over OH and OD or from the kinetics of Br2 consumption in excess of OH and OD: k1 = (1.8 ± 0.3) × 10−11 exp [(235 ± 50)/T] and k3 = (1.9 ± 0.2) × 10−11 exp [(220 ± 25)/T] cm3 molecule−1 s−1. For the reaction channels of the title reactions: OH + Br2 → BrO + HBr and OD + Br2 → BrO + DBr, the upper limits of the branching ratios were found to be 0.03 and 0.02 at T = 320 K, respectively.