Electron releasing groups( e. g.,-CH3,-OCH3,-NH2 etc.) increase the basic strength of aromatic amines while electron withdrawing groups( like – NO2,-X,-CN etc.) tend to decrease the same.
o-substituted aromaticamines are usually weaker basesthan aniline irrespective of the nature of substituent whether electron releasing or electron withdrawing. This is called ortho effect and is probably due to sterk and electronic factors.
Chemical Properties of Amines
( i) Alkylation All the three types of amines react with alkyl halides to form quaternary ammonium salt as the final product provided alkyl halide is present in excess.
Aromatic amines also undergo alkylation as given below.