Rimary amines (R—$N{ H }_{ 2 }$) have higher boiling point than tertiary amines (R3N)

cbse
amines

#1

Account for the following.
(i) Primary amines (R—$N{ H }_{ 2 }$) have higher boiling point than tertiary amines (R3N).
(ii) (CH 3)2NH is more basic than (CH 3)sN in an aqueous solution.


#2

(i) Intermolecular hydrogen bonding is present in primary amines but not in tertiary amines, so primary amines have higher boiling point than tertiary amines.
(ii) Basic strength of (CH3)2NH and (CH3)3N depends upon the stabilisation of their conjugate acids by a number of factors such as H-bonding, steric hindrance of alkyl groups and +/-effect of alkyl groups.
The first two factors are favourable for 2° amines, hence (CH3 )2NH is a stronger base than (CH3)3N.