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 ...

Benzenesulphonyl chloride reacts with primary amines to form sulphonamides, such as N-ethylbenzenesulphonyl amide. The sulphonyl group imparts acidity to the hydrogen attached to nitrogen, making it soluble in alkali.

Aromatic amines react with nitrous acid at low temperatures to form diazonium salts, a crucial class of compounds employed in the synthesis of various aromatic compounds. Secondary and tertiary amines exhibit different reactions with nitrous acid.

Primary aliphatic amines, when treated with nitrous acid, form unstable aliphatic diazonium salts that quantitatively release nitrogen gas and alcohols. The quantitative evolution of nitrogen is used for the estimation of amino acids and proteins.