Kinetics and mechanism of the C2H5O2 + NO reaction: A temperature and pressure dependence study using chemical ionization mass spectrometry

The overall rate coefficient (k1) for the reaction of C2H5O2 + NO has been measured using the turbulent flow CIMS technique. The temperature dependence of the rate coefficient was investigated between 203 and 298 K. Across the temperature range, the experimentally determined rate coefficients showed good agreement with previous studies and were fitted using an Arrhenius type analysis to yield the expression k1 = (1.75) × 10−12 exp[(462 ± 19)/T] cm3 molecule−1 s−1. Experiments were carried out in the pressure range of 100–200 Torr within the stated temperature range, where the rate coefficients were shown to be invariant with pressure. The branching ratio of the reaction was also assessed as a function of temperature and was found to proceed 100 ± 5% via the C2H5O + NO2 reactive channel. This work represents the first temperature and pressure study over which the branching ratio has been studied. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 253–260, 2005