Account for the following:
Gabriel phthalimide synthesis is preferred for the synthesizing amines.

Gabriel phthalimide synthesis results in the formation of primary amine only. secondary or tertiary amines are not formed in this synthesis. thus, the pure primary amine can be obtained. Therefore, Gabriel phthalimide synthesis is preferred for synthesising primary amines.
Phthalimide is alkylated with alkyl or benzyl halide and then hydrolysed or hydrazinolysis to get pure primary amine. In this method, phthalic acid is produced which can be again converted into phthalimide and used over and over again.