Amine is a type of compound that is derived from ammonia, i.e., NH3. We can simply say, that amines are derivatives of ammonia. We study about amines in Organic Chemistry, and they are basically classified as functional groups or organic nitrogen compounds that contain a nitrogen atom with a lone pair. Generally, in amines, hydrogen atoms are substituted by an aryl or alkyl group.
Amine functional group is represented by: -NH2 group, e.g., CH3NH2
Type of amine
It is of three types:
- Primary amines (-NH2), e.g., CH3NH2 (methylamine)
- Secondary amines (-NH-), e.g., (CH3)2NH (dimethylamine)
- Tertiary amines (-N-), e.g.,(CH3)3N (trimethylamine)
Test to distinguish between amines
- Carbylamine test
- Hinsberg reagent test
Test used to distinguish between primary and secondary amine
Carbylamine test
Carbylamine test is only given by primary amines.
Ethylamine is a primary amine, so on reaction with chloroform and potassium hydroxide, a foul smelling compound, i.e., ethyl isocyanide is formed.
Diethylamine does not give carbylamine test.
Reaction for ethylamine is:
C2H5NH2 + CHCl3 + 3 NaOH → C2H5NC + 3 NaCl + 3 H2O
C2H5NC is foul smelling compound.
Read more: How carbylamine reaction give foul smelling compound?
Hinsberg test
Hinsberg test is a chemical reaction that is used to distinguish between primary, secondary, tertiary amines.
Ethylamine (primary amine) on reacting with benzene sulphonyl chloride form a base soluble compound, while diethylamine (secondary amine) on reacting with benzene sulphonyl chloride form a base insoluble compound.
In case of tertiary amines, the Hinsberg test gives salt of benzene sulphonic acid and tertiary amine reacts with HCl to form amine hydrochloride salt.
Hence, to distinguish between ethylamine and diethylamine, both Carbylamine test and Hinsberg test can be used.