Interaction of Aniline with Diazotising and Nitrating Agents in Concentrated Sulfuric Acid

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.