Question

Why does nitration aniline give meta directed nitro compounds?

Answer 1

Nitration takes place in presence of conc HN 3 and conc H2SO4, both these acid give H+ ions.

Aniline being a Lewis base, accepts the H+ ions and forms anilinium ion. The anilinium ion carrying a positive charge on nitrogen will pull the electrons towards itself making it meta directing. Hence nitration of aniline give meta nitroaniline as the major product along with para nitroaniline.

Note : To avoid meta product the reaction can be carried out in acetyl medium, where acetaniline is formed which is Ortho para directing which on hydrolysis yields o and p nitro aniline