Nitration of Acetanilide

Acetanilide is a derivative of aniline and it contains an acetyl group (-COCH3) attached to the amino group (-NH2) of aniline. When acetanilide is nitrated, the nitration takes place at the para position of the benzene ring due to the electron withdrawing effect of the acetyl group.

The reaction takes place in the presence of a mixture of concentrated nitric acid and concentrated sulfuric acid. The sulfuric acid acts as a dehydrating agent and removes the water produced during the reaction.

The product obtained after nitration is a mixture of ortho, meta, and para nitroacetanilide. However, the para isomer is the major product due to the steric hindrance caused by the acetyl group which makes the ortho position less accessible for the incoming nitro group.

Alkaline Hydrolysis of Nitroacetanilide

The nitroacetanilide obtained after nitration is not useful and needs to be converted into a more useful product. The nitro group can be easily converted into an amino group by alkaline hydrolysis.

In this reaction, the nitroacetanilide is treated with sodium hydroxide (NaOH) in water. The alkaline conditions break the nitro group (-NO2) and convert it into an amino group (-NH2).

The product obtained after alkaline hydrolysis depends on the position of the nitro group in the starting material. In the case of nitroacetanilide, the para isomer is obtained after hydrolysis. This is because the para position is less hindered compared to the meta position, which makes it easier for the hydroxide ion to attack the nitro group.

Therefore, the main product obtained after nitration and alkaline hydrolysis of acetanilide is p-nitroaniline.