Amines are classified on the basis of the number of hydrogen atoms of ammonia that are replaced by alkyl group. Amines are classified as primary (1°), secondary (2°) and tertiary (3°).
(1) Primary amines (1° amines) : The amines in which only one hydrogen atom of ammonia is replaced by an alkyl group or aryl group are called primary (1°) amines.
Examples :
(i) CH3 – NH2 methylamine
(ii) CH3 – CH2 – NH2 ethylamine
(2) Secondary amines (2° amines) : The amines in which two hydrogen atoms of ammonia are replaced by two, same or different alkyl or aryl groups are called secondary (2°) amines.
Examples :
(i) C2H5 – NH – CH3 ethylmethylamine
(ii) CH3 – NH – CH3 dimethylamine
(3) Tertiary amines (3° amines) : The amines in which all the three hydrogen atoms of ammonia are replaced by three same or different alkyl or aryl groups are called tertiary (3°) amines.
Examples :
Secondary and tertiary amines are further classified as
(1) Simple or symmetrical amines
(2) Mixed or unsymmetrical amines.
(i) Simple or symmetrical amines : In simple amines same alkyl groups are attached to the nitrogen e.g.
(ii) Mixed or unsymmetrical amines : In mixed amines different alkyl groups are attached to the nitrogen.
