Describe the Hinsberg’s test for identification of primary, secondary and tertiary amines. Also write the chemical equations of the reactions involved.
Hinsberg test: Benzenesulphonyl chloride (C6H5SO2Cl)(C6H5SO2Cl) , commonly known as Hinsberg's reagent, forms sulphonamides when it interacts with primary and secondary amines. For Primary Amines: N-ethylbenzenesulphonyl amide is produced by reacting benzenesulphonyl chloride with primary amine. Because of the strong electron withdrawing sulphonyl group, the hydrogen linked to nitrogen in sulphonamide is highly acidic. As a result, it is alkali soluble. For Secondary Amines: N,N-diethylbenzenesulphonamide is produced in the reaction with secondary amine. It is not acidic and hence insoluble in alkali because N, N-diethylbenzene sulphonamide has no hydrogen atom linked to the nitrogen atom. For Tertiary Amines: Benzenesulphonyl chloride does not react with tertiary amines. This characteristic of amines reacting differently with benzenesulphonyl chloride is used to distinguish primary, secondary, and tertiary amines, as well as to separate a mixture of amines.
