Preparation of aromatic azoamines by diazotization/coupling/rearrangement of aromatic amines

In a process for the preparation of an aromatic azoamine, comprising diazotizing an aromatic amine, coupling the thus prepared diazonium salt with the aromatic amine, and thence rearranging the resulting aromatic diazoamine, the improvement which comprises effecting said diazotization, coupling and rearrangement reactions by introducing vaporous nitrogen oxides comprising an admixture of nitric oxide, NO.sub.1, and nitrogen peroxide, NO.sub.2, or nitrogen trioxide, N.sub.2 O.sub.3, wherein the molar ratio of said nitric oxide to said nitrogen peroxide or nitrogen trioxide is between about 2:1 and about 100:1, to a reaction medium including the aromatic amine [.alpha.], a salt of the aromatic amine [.beta.], and water [.gamma.], with the percentage weight relationship existing among the components .alpha., .beta. and .gamma. being such that:

• 10<.alpha.<70
• 13<.beta.
• 5<.gamma.
• .alpha.+.beta.+.gamma.=100.