Question

28. Give reasons.
i Aniline does not undergo Friedal-Crafts reaction.
ii Aromatic primary amines cannot be prepared by Gabriel's phthalimide synthesis.
11. Aliphatic amines are stronger bases than ammonia.​

Answer 1

Answer:

A) A Friedel-Crafts reaction is carried out in the presence of AlCl3. But AlCl3 used as catalyst and is acidic in nature i.e ., Lewis acid whereas aniline is a strong Lewis base. Thus, aniline reacts with AlCl3 to form a salt.

B) Aromatic primary amines cannot be prepared by Gabriel phthalimide synthesis as aryl halides do not undergo nucleophilic substitution with the salt formed by phthalimide.

C) Aliphatic amines are stronger bases than ammonia due +I (electron releasing) effect of alkyl groups. The electron density on N increases and lone pair of electrons can be easily donated.