Direct kinetics study of the temperature dependence of the CH2O branching channel for the CH3O2 + HO2 reaction
A direct kinetics study of the temperature dependence of the CH2O branching channel for the CH3O2 + HO2 reaction has been performed using the turbulent flow technique with high-pressure chemical ionization mass spectrometry for the detection of reactants and products. The temperature dependence of the CH2O-producing channel rate constant was investigated between 298 and 218 K at a pressure of 100 Torr, and the data were fitted to the following Arrhenius expression: 1.6−0.7+1.0 × 10−15 × exp[(1730 ± 130)/T]; cm3 molecule−1 s−1. Using the Arrhenius expression for the overall rate of the CH3O2 + HO2 reaction and this result, the 298 K branching ratio for the CH2O producing channel is measured to be 0.11, and the branching ratio is calculated to increase to a value of 0.31 at 218 K, the lowest temperature accessed in this study. The results are compared to the analogous CH3O2 + CH3O2 reaction and the potential atmospheric ramifications of significant CH2O production from the CH3O2 + HO2 reaction are discussed.
Elrod, M.J., D.L. Ranschaert, and N.J. Schneider. 2001. "Direct Kinetics Study of the Temperature Dependence of the CH2O Branching Channel for the CH3O2 + HO2 Reaction." International Journal of Chemical Kinetics. 33(6): 363-376.
International Journal of Chemical Kinetics
Chemistry and Biochemistry