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 .