This is a very convenient method for the preparation of pure aliphatic primary amines. Phthalimide on treatment with ethanolic KOH gives potassium phthalimide which on heating with a suitable alkyl halides gives an N- substituted phthalimides followed by the subsequent hydrolysis to give corresponding primary amines.

Note: Aromatic primary amines such as aniline cannot be prepared by this method because aryl halides do not undergo nucleophilic substitution reaction with potassium phthalimide under mild conditions