Kinetics and mechanism of the reaction of CH3O with NO

✍ Scribed by S. Dóbé; G. Lendvay; I. Szilágyi; T. Bérces

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 778 KB
• Volume: 26
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550260903

✦ Synopsis

Abstract

The kinetics of the reaction of CH~3~O with NO and the branching ratio for HCHO product formation, obtained as Γ~HCHO~ = (Rate of HCHO formation) / (Rate of CH~3~O decay), have been studied using a discharge flow reactor. Laser induced fluorescence has been used to monitor the decay of the CH~3~O radical and the build‐up of the HCHO product. Overall rate constants and product branching ratios were measured at room temperature over the pressure range of 0.72–8.5 torr He. Three reaction mechanisms were considered which differed in the routes of HCHO formation: (i) direct disproportionation; (ii) via an energized collision complex; or (iii) both reaction routes. It has been shown that data on the pressure dependence of the overall rate constant are not sufficient to distinguish between these mechanisms. In addition, an accurate value of Γ is required. Analysis of the available experimental data provided 0.0 and about 0.1 as the lower and upper limit for Γ, respectively. Since the rate constants derived for CH~3~ONO formation were not sensitive to the value assumed for Γ, k = (1.69 ± 0.69) × 10^−29^ cm^6^ molecule^−2^ s^−1^ and k = (2.45 ± 0.31) × 10^−11^ cm^3^ molecule^−1^ s^−1^ could be derived. The rate constant obtained for formaldehyde formation when extrapolated to zero pressure is k = (3.15 ± 0.92) × 10^−12^ cm^3^ molecule^−1^ s^−1^. © 1994 John Wiley & Sons, Inc.