In most of its reaction, amines act as a nucleophile or a base due to lone pair on nitrogen. In aromatic amines, due to resonance, the -NH2 group make the ring more susceptible to electrophilic substitution at ortho and para position.
Important reactions of amines are classified as :
1. Salt formation
Amines are soluble in mineral acids and carboxylic acids, due to the formation of soluble ammonium salts.
RNH2 + HCl -------> RNH3+ Cl-
C6H5NH2 --------> C6H5NH3+ Cl-
Alkyl halides when react with primary or secondary amines undergo nucleophilic substitution. When HX is removed, secondary or tertiary amine formed will again reacts with alkyl halide froming tertiary amine and finally quaternary ammonium salt.
4. Reaction with carbonyl compounds
5. Carbylamine reaction
6. Reaction with nitrous acids
With nitrous acid primary, secondary and tertiary amines react differently and give different product. Hence this reaction can be used to distinguish primary, secondary and tertiary amines from each other.
For more visit Physical Properties of Amine