Primary, secondary and tertiary amines can be separated using para-toluene sulphonyl chloride. This test is known as Hinsberg test. Reaction involved are as follows: Primary (1∘) amine Primary amines react with para toluene sulphonyl chloride to form a precipitate that is soluble in NaOH.
Secondary (2∘) amine Secondary amines reacts with para toluene sulphonyl chloride to give a precipitate that is insoluble in NaOH.
Tertiary (3∘) amine Tertiary amines do not react with para toluene.