Question: Describe two synthetic routes for the preparation of p-methoxyaniline from benzene.

The benzene reacts with the bromine FeBr₃ in to produce the bromobenzene. The nitration of benzene can be carried out by using the reagents HNO₃ and H₂SO₄. These reactions constitute the examples of electrophilic aromatic substitution reaction.

In the first method, the benzene reacts with Br₂ and FeBr₃ to form the bromobenzene. This further reacts with HNO₃ and H₂SO₄. to form 1-bromo-4-nitrobenzene. This reacts with CH₃O and heat to form 1-methoxy-4-nitrobenzene.

This further reacts with H₂ in the presence of the Pd catalyst to form 4-methoxyaniline. The reaction is shown below.

First method to prepare p-methoxyaniline from benzene

In the second method, the benzene reacts with HNO₃ and H₂SO₄. to form the nitrobenzene. This further reacts with in the presence of a palladium catalyst to form the aniline. It further reacts with HCl and NaNO₂ at zero degrees Celsius to form the benzene diazonium chloride. This reacts with methanol, HCl, and heat to form the anisole.

This reacts with HNO₃ and H₂SO₄. to form 1-methoxy-4-nitrobenzene. This reacts with H₂ in the presence of a Pd catalyst to form 4-methoxyaniline. The reaction is shown below.

Second method to prepare p-methoxyaniline from benzene