Hinsberg’s test can be used to identify and discriminate primary, secondary, and tertiary amines. The amines are allowed to react with Hinsberg’s reagent, benzene sulphonyl chloride(C6H5SO2 Cl). Hinsberg’s reagent reacts differently with the three types of amines. As a result, Hinsberg’s reagent can be used to easily identify them.
N-alkyl benzene sulphonyl amide is formed when primary amines react with benzene sulphonyl chloride to produce an alkali-soluble N-alkyl benzene sulphonyl amide.
The H – atom bound to nitrogen can be easily released as a proton due to the presence of a strong electron-withdrawing sulphonyl group in the sulphonamide. As a result, it’s acidic and will dissolve in alkali.
Secondary amines react with Hinsberg’s reagent to give a sulphonamide which is insoluble in alkali.
In sulphonamide, there is no H-atom linked to the N-atom.
As a result, it is not acidic and is alkali-insoluble. Tertiary amines, on the other hand, do not react with Hinsberg’s reagent at all.
