The Reaction of Methyl Radicals with Nitric Oxide, and the Rate of Combination of Methyl Radicals

Radioactive tellurium mirrors have been used to investigate the rate of reaction of methyl radicals with nitric oxide in a flow system. The collision efficiency of this reaction has been found to be 1.5×10⁻⁴, which is higher by a factor of 10 than the previous value obtained by Forsyth. This value when applied to results obtained by Miller and Steacie for the ratio of the two reactions $${\mathrm{CH}}_3+{\mathrm{CH}}_3\to {\mathrm{C}}_2{\mathrm{H}}_6,$$ $${\mathrm{CH}}_3+\mathrm{NO}\to \mathrm{products},$$ leads to a collision efficiency or steric factor, assuming the activation energy to be zero, of 0.01 for methyl combination. A comparison of this value with those obtained by other authors from photochemical studies suggests the value for the collision efficiency of methyl combination is between 0.5 and 0.05.