N,N-Dialkyl aromatic amines react rapidly with nitrous acid to competitively produce a nitrosamine and a nitro compound. The mechanism of nitro compound formation involves a reaction of an amine radical cation with NO2, while the nitrosamine is produced by two competing pathways, one of which involves N-alpha-CH deprotonation of a radical cation with subsequent oxidative generation of an imminium ion, and the other of which occurs through NOH elimination of a nitrosammonium ion (R3N-N=O+). All three pathways are linked through the reversible homolysis of R3N-N=O+ to NO and a radical cation.