Acetylation with acetic anhydride protects the -NH₂ group in aniline during electrophilic substitution, and the resulting -NHCOCH₂ group has a less activating effect due to resonance interactions that make the lone pair on nitrogen less available for donation to the ...

Aromatic amines, like aniline, exhibit very high reactivity in electrophilic substitution, favoring ortho- and para-positions. To control the activating effect of the -NH₂ group for monosubstitution, acetylation with acetic anhydride can be performed, followed by desired substitution and hydrolysis of ...

The -NH₂ group in aniline is ortho- and para-directing, making these positions centers of high electron density in its resonance hybrid structures.

Tertiary amines do not react with benzenesulphonyl chloride, providing a basis for distinguishing between primary, secondary, and tertiary amines. This property is employed for the separation of amine mixtures. Nowadays, p-toluenesulphonyl chloride is commonly used in place of benzenesulphonyl chloride.

The reaction of benzenesulphonyl chloride with secondary amines yields N,N-diethylbenzenesulphonamide, which lacks acidic hydrogen and is insoluble in alkali due to the absence of a hydrogen atom attached to the nitrogen.