Question

Give a chemical test to distinguish between primary and secondary amines

Answer 1

Identification of primary , secondary,tertiary amines is done by reacting them with Benzenesulphonyl chloride.

A. The reaction of benzene sulphonyl chloride with primary amine yields N-Ethylbenzenesulphonyl amide.

The hydrogen attached to nitrogen in N -ethylbenzenesulphonamide is acid so soluble in alkali solution .

B. when benzenesulphonyl chloride reacts to the with secondary amine it forms N,N dimethylbenzenesulphonyl amide.

The formed N,N has no hydrogen attached to nitrogen hence it is not acidic so it’s insoluble in alkaline solution.

C. Tertiary amines doesn’t show any reaction with benzenesulphonyl chloride.

D. Based on reaction of benzenesulphonyl chloride with amines and solubility of their products in alkaline they are identified.