Reactions of diazonium salts are broadly categorized into two types: (A) reactions involving displacement of nitrogen and (B) reactions involving retention of the diazo group.

Benzoylation is a specific acylation reaction where amines react with benzoyl chloride (C₆H₅COCl). Pyridine, a base stronger than the amine, is used in acylation reactions to remove HCl formed during the reaction and shift the equilibrium towards the right.

Aliphatic and aromatic primary and secondary amines undergo acylation, a nucleophilic substitution reaction with acid chlorides, anhydrides, and esters. The products of acylation reactions are known as amides.

Amines undergo alkylation when they react with alkyl halides, resulting in the substitution of hydrogen atoms with alkyl groups.

Electron-releasing groups like –OCH₃, –CH₃ increase the basic strength of substituted aniline, while electron-withdrawing groups like –NO₂, –SO₃H, –COOH, –X decrease it. This observation highlights the role of substituents in influencing the basic nature of aromatic amines.

Aniline, with five resonating structures, is more stable than the anilinium ion, which has only two resonating structures (kekule). The greater stability of aniline contributes to its lower proton acceptability or basic nature compared to ammonia.

Aniline’s higher pKb value is attributed to the -NH₂ group being directly attached to the benzene ring, causing the unshared electron pair on nitrogen to be in conjugation with the benzene ring, making it less available for protonation.

The basic strength of alkyl amines in aqueous solution is influenced by the interplay of inductive effect, solvation effect, and steric hindrance of the alkyl group. This interplay determines the subtle changes in the order of basic strength, especially with ...

Benzenediazonium chloride is a colorless crystalline solid, readily soluble in water, stable in cold but reacts with water when warmed, and decomposes easily in the dry state. Benzenediazonium fluoroborate is water-insoluble and stable at room temperature.

Benzenediazonium chloride is prepared by the diazotization of aniline with nitrous acid at 273-278 K. Due to their instability, diazonium salts are not generally stored and are used immediately after preparation.