High Temperature Reactions of CH₃ 1. The Reaction CH₃ + H₂ → CH₄ + H

Abstract

The rate coefficient of the reaction CH3 + Hz 4 CH4 + H was determined at high temperatures behind incident shock waves by timeresolved measurements of the absorption of the methyl radical at 216.5 nm. The resulting Arrhenius expression k3 = 1013.3~0.~ exp( -(72OO f 400) KIT) cm3 mol-' s-' is in good agreement with earlier indirect measurements. Several methyl radical sources are compared.

High Temperature Reactions of CH3 2. H‐Abstraction from Alkanes

“…Methyl concentration was measured by following the absorption at 216.5 nm, the second beam was used to follow the absorption of the parent compound at shorter wavelengths. The results of those latter observations have been reported recently [3]. The absorption profiles at 216.5 nm show the typical behaviour of the rapidly formed and somewhat slower consumed methyl radical.…”

“…After passing the shock tube the beam was divided by a quartz plate, focussed on the entrance slits of two monochromators and detected by photomultiplier tubes. The apparatus was identical to that described in our previous study of the kinetics of the reaction of CH3 with molecular hydrogen [3],…”

The use of transition‐state theory to extrapolate rate coefficients for reactions of H atoms with alkanes

“…The lowesttemperature measurements of k -l were those of Gesser and Steacie [12] (372 < T/K < 480). More recent measurements include those of Moller et al [13] in a shock tube (1070 < T/K < 2320,30 < p/torr < 121); of Baldwin et al [14] at 753 K, relative to reaction of CH3 + CH3 -+ CzH6 (kI2); and of Marshall and Shahkar [15] by a novel technique not involving a relative measurement (584 < T/K < 671,5 < p/torr < 26).…”

An investigation of the reaction between CH3 radicals and methanol at high temperatures

“…The obviously positive deviation of a linear Arrhenius behavior towards high temperatures was expected. It was also observed in several other H-atom abstractions by methyl radicals as for example in for which the H atoms are equal [12,131. The results of this work and the corresponding low temperature data are shown in the Arrhenius plot ( Fig.…”