Question

Amines are classified as primary, secondary and tertiary amine.

a) Represent the structure of secondary and tertiary amine.

b) How will you convert nitrobenzene to aniline?

c) Aniline does not undergo Friedel-Crafts reaction. Why?

Answer 1

b) Nitrobenzene on reduction by passing hydrogen gas in the presence of finely divided nickel, palladium or platinum and also by reduction with metals(Sn or Fe) in acidic medium gives aniline.

Or, the chemical equation:

c) Aniline does not undergo Friedel- Crafts reaction (alkylation and acetylation) due to salt formation with aluminium chloride, the Lewis acid, which is used as a catalyst. Due to this, nitrogen of aniline acquires positive charge and hence acts as a strong deactivating group forfurther reaction.