Give reasons for the following:
Aniline does not undergo Friedal- Crafts reaction.
Account for the following :
Aniline does not undergo Friedel – Crafts reaction.
Solution 1
Aniline does not undergo Friedel-Crafts reaction:
A Friedel-Crafts reaction is carried out in the presence of AlCl3. But AlCl3 is acidic in nature, while aniline is a strong base. Thus, aniline reacts with AlCl3 to form a salt (as shown in the following equation).
Due to the positive charge on the N-atom, electrophilic substitution in the benzene ring is deactivated. Hence, aniline does not undergo the Friedel-Crafts reaction.
Solution 2
AlCl3 is acidic and aniline is basic in nature. They react with each other to form a salt. As a result, a positive charge is developed on the N-atom and electrophilic substitution in the benzene ring is deactivated. Hence, aniline does not undergo Friedel–Crafts reaction.
`C_6H_5NH_2+AlCl_3 -> C_6H_5NH_2 ""^(+)AlCl_3^(-)`
