Temperature‐dependent rate constants for the reactions of chlorine atom with methanol and Br2

Abstract

AbstractKinetics of the reaction of Cl atoms with methanol has been investigated at 2 Torr total pressure of helium and over a wide temperature range 225‐950 K, using a discharge flow reactor combined with an electron impact ionization quadrupole mass spectrometer. The rate constant of the reaction Cl + CH3OH → products (1) was determined using both absolute measurements under pseudo‐first order conditions, monitoring the kinetics of Cl‐atom consumption in excess of methanol and relative rate method, k1 = (5.1 ± 0.8) × 10−11 cm3 molecule−1 s−1, and was found to be temperature independent over the range T = 225‐950 K. The rate constant of the reaction Cl + Br2 → BrCl + Br (3) was measured in an absolute way monitoring Cl‐atom decays in excess of Br2: k3 = 1.64 × 10−10 exp(34/T) cm3 molecule−1 s−1 at T = 225‐960 K (with conservative 15% uncertainty). The experimental data for k3 can also be adequately represented by the temperature independent value of k3 = (1.8 ± 0.3) × 10−10 cm3 molecule−1 s−1. The kinetic data from the present study are compared with previous measurements.