The Reactions of Methyl and Acetyl Radicals with the Oxides of Nitrogen

Some of the reactions of methyl and acetyl radicals with the oxides of nitrogen have been investigated by photolyzing either acetone or biacetyl in the presence of nitric oxide, or nitrogen dioxide in the presence of acetaldehyde. A most important reaction in all these studies was found to be addition of methyl radicals to nitrogen dioxide to form nitromethane: CH 3 + NO 2 (+M) → CH 3 NO 2 (+M). The metathetical reaction: CH 3 + NO 2 → CH 3 O + NO was found to be measurable but of lesser importance. Addition of nitrogen dioxide to methyl radicals to produce methyl nitrite: CH 3 + NO 2 → CH 3 ONO, occurred to a negligible extent if at all under the conditions of our experiments. It appears that if nitrosomethane is formed by the addition reaction: CH 3 + NO(+M) → CH 3 NO(+M), then it is mainly removed by reaction with excess nitric oxide or at appreciable nitrogen dioxide concentrations by the displacement reaction: CH 3 NO + NO 2 → CH 3 NO 2 + NO.