Investigation of the CH₃ + NO reaction in shock waves

Abstract

The reaction of CH3 + NO was investigated behind incident shock waves at temperatures between 1300 K and 2080 K. The formation of H atoms and of HCN was studied by time resolved UV absorption and by IR‐emission. OH measurements of Hoffmann et al. were reevaluated with the rate constant of this work. The rate constant for the reaction of CH3 + NO can be expressed byk = (4.0 ± 0.8)·1012 exp (−(8500 ± 500) K/T) cm3 mol−1 s−1.HCN was found to be the main final product of the reaction of CH3 + NO in the temperature range covered. The contribution of the H forming channels is around 20–25% to the main channel.

The CH3+NO rate coefficient at high temperatures: Theoretical analysis and comparison with experiment

“…We compare our predictions for with this data in k T Figure 2. The agreement of our results with the most recent experiments of Hennig and Wagner [15] and Braun -Unkhoff, et al [14] is remarkably good over the entire temperature range of their experiments. However, there are more serious discrepancies between the theory and the experiments of Yang et al [17] and those of Wolff and Wagner [19], probably more than could be accounted for by theoretical inaccuracies, the most important of which are possible errors in the potential energy barriers.…”

“…k ϭ 3.0 ϫ 10 T exp(Ϫ 3950/RT) cm /mole-s, T 3 in the temperature range is in 1000 K Յ T Յ 2500 K, excellent agreement with the most recent shock-tube experiments of Hennig and Wagner 15 and BraunUnkhoff et al [14].…”

“…2 Taking our result for and their result for k 1 , we k T would conclude that at i.e., k /k Ϸ 0.3 T ϭ 1200 K, 1 T the radical channel is dominant at this temperature. However, this conclusion appears to be inconsistent with the experimental results of Hennig and Wagner [15] and Braun -Unkhoff et al [14], both of whom conclude that the molecular channel is the dominant one even at higher temperatures. Of course, the importance of the radical channel should increase with increased T.…”

Combustion Chemistry of Nitrogen

“…1993;Lifshitz et a1. 1993;Hennig and Wagner 1994). These data and earlier measurements are summarized in Figure 2.37.…”

“…Entropy and heat capacity values were computed in MOPAC with the THERMO option for vibrations and overall rotation; contributions from frequencies corresponding to internal rotations were replaced by Pitzer-Gwinn estimates of the rotational entropy and heat capacity. --e-- Hennig-Wagner (1994) total --<>--- Lifshitz et al (1993) HCN + H2O…”