Reactions of atomic nitrogen and atomic hydrogen with methylacetylene

The reaction of nitrogen atoms with methylacetylene has been studied using a fast‐flow low‐pressure reactor coupled to a mass spctrometer by a nozzle‐beam sampling system. Hydrogen atom concentrations were measured by ESR analysis. Experimental second‐order rate constants for the consumption of N atoms, of C 3 H 4 , and for the formation of N 2 were determined in the temperature range of 283° to 485°K. Product profiles of all stable species and of hydrogen atoms and methyl radicals were obtained for different initial concentrations of the reactants. Two different reaction pathways can be distinguished: one provides for recombination of N atoms, and the second leads to the formation of cyano compounds and other hydrocarbons. Only the latter process is influenced by the addition of hydrogen atoms. Mechanisms for the two pathways are discussed.