Question

How do you convert:
Chlorobenzene to biphenyl

Hint:

The Wurtz-Fittig reaction is used for coupling two aromatic rings to form biphenyl.

Answer 1

Conversion of Chlorobenzene to Biphenyl:

The conversion of chlorobenzene (C₆H₅Cl) to biphenyl (C₆H₅-C₆H₅) involves a reaction known as the **Wurtz-Fittig Reaction**. This reaction is a type of cross-coupling reaction where two aryl halides are coupled in the presence of sodium metal.

Reaction:

2 C₆H₅Cl + Na → C₆H₅-C₆H₅ + 2 NaCl

Mechanism:
1. The reaction is carried out in dry ether and requires heat. Sodium metal donates electrons to the chlorobenzene, generating a phenyl radical (C₆H₅•) and sodium chloride (NaCl). 2. The phenyl radicals couple together to form biphenyl (C₆H₅-C₆H₅).

Conditions:
- Sodium metal (Na) is used as a reducing agent.
- The reaction takes place in the presence of anhydrous ether to prevent moisture from interfering with the reaction.

Conclusion:
By heating chlorobenzene with sodium metal in ether, chlorobenzene undergoes a Wurtz-Fittig reaction to form biphenyl.