Question

How is chlorobenzene prepared from aniline? How is chlorobenzene converted into diphenyl?

Answer 1

Hint: We can prepare chlorobenzene from aniline by using Sandmeyer reaction, by using fittig reaction we can prepare diphenyl from chlorobenzene.

Complete step by step answer:
Sandmeyer reaction: “The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. It is an example of a radical-nucleophilic aromatic substitution”.
It is a two-step reaction
In the first step aniline is going to convert to benzene diazonium chloride using sodium Nitrate and aqueous hydrochloric acid.

In the second step benzene diazonium chloride reacts with cuprous chloride and forms chloro benzene. Aryl diazonium chloride is very reactive, whenever aryldiazonium chloride forms it will react with cuprous chloride and forms chlorobenzene.

Fittig reaction: “Fittig reaction is the chemical reaction of aryl halides with sodium metal in the presence of dry ether to give substituted aromatic compounds”.
Two moles of chlorobenzene react in presence of sodium and dry ether and forms biphenyl compounds and 2 moles of sodium chloride (insoluble in dry ether).

Note: Don’t be get confused with Sandmeyer reaction and Fittig reaction
Sandmeyer reaction: Preparation of chlorobenzene from Aniline by using sodium nitrate, aq. Hydrochloric acid and cuprous chloride.
Fittig reaction: Preparation of Diphenyl form Chlorobenzene by using sodium metal and dry ether.