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The interaction of aniline with nitrosonium hydrogensulfate then with nitric acid in concentrated sulfuric acid does not occur through diazotisation and subsequent nitration of the benzenediazonium ion, but instead involves nitrosonium ion catalysed nitration of anilinium ion in the para -position together with uncatalysed nitration in the meta - and para -positions followed by diazotisation on dilution with water.

The N(α), N(β)-rearrangement of the two N-atoms which can be observed in solutions of [β-15N]-labelled p-substituted benzenediazonium ions follows dual substituent parameter treatments. The reaction yields a negative field and a positive resonance reaction constant (pF =−3.35, pR = 2.47). The magnitude of these constants is, within experimental error, the same as the respective reaction constants for solvolytic dediazoniation. The exchange of the diazonio group of 15N-labelled p-substituted benzenediazonium ion yields, however, field and resonance reaction constants which are close to zero. This result is attributed to cancellation of the reaction constants for the forward and reverse steps in the complex mechanism of the exchange reaction.

The reaction of benzenediazonium ion generated from α-azohydroperoxide with 1-naphthol gave a diazoether which rearranged to 2- and 4-phenylazo-1-naphthols.

The preparation and spectral properties of twenty-five arylazocyanoacetarylamides (VI–VIII) are investigated. Analysis of the IR and UV spectra of such compounds (VI–VIII) shows that they are of the hydrazo rather than the azo form. The reaction of benzenediazonium ion and the arylazo derivatives (VI and VII) in the presence of sodium hydroxide (and not in the presence of sodium acetate) produces 3-cyano-1,5-diarylformazans (IX). A mechanism is suggested for the formation of formazans (IX). Reaction of (VI–VII) with Grignard reagents results in 1,2-addition to the cyanide group with the formation of arylazoiminoacylacetanilides (X), which were hydrolysed to the corresponding arylazoacylacetanilides (XI). The UV spectral properties of compounds X and XI are compared.

The reaction of benzenediazonium ion generated from α-azohydroperoxide with 1-naphthol gave a diazoether which rearranged to 2- and 4-phenylazo-1-naphthols.

The N(α), N(β)-rearrangement of the two N-atoms which can be observed in solutions of [β-15N]-labelled p-substituted benzenediazonium ions follows dual substituent parameter treatments. The reaction yields a negative field and a positive resonance reaction constant (pF =−3.35, pR = 2.47). The magnitude of these constants is, within experimental error, the same as the respective reaction constants for solvolytic dediazoniation. The exchange of the diazonio group of 15N-labelled p-substituted benzenediazonium ion yields, however, field and resonance reaction constants which are close to zero. This result is attributed to cancellation of the reaction constants for the forward and reverse steps in the complex mechanism of the exchange reaction.

The conversion of p -CH 3 OC 6 H 4 N 2 + to the hydrazine and then to the benzaldehyde hydrazone gave a stable substance in which the proton NMR could be used to locate a 15 N label. In contrast to an earlier study on benzenediazonium ion by a similar method, this analysis showed that the α- 15 N label in the diazonium salt migrates during hydrolysis to the β position to about the extent indicated by a degradative method.

1-Phenyl-3,3-dimethyltriazene (1; X = H) is a stable source for the benzenediazonium ion which is in eaquilibrium with the betaine (2) and hence can kgive rise to products derived from benzyne and phenyl radicals: on the other hand, the analogous 2,3,4,5-tetrahalogenophenyltriazenes (1; X = F or Cl) do not lead to arynes.