Question

What happens when chlorobenzene is treated with ethyl chloride in the presence of sodium in dry ether?

Answer 1

1. When chlorobenzene and ethyl chloride are treated with sodium in dry ether, the main product is ethylbenzene, formed via the Wurtz-Fittig reaction.
2. Wurtz-Fittig reaction a combination of Wurtz reaction and Fittig reaction used for coupling aryl halides with alkyl halides.
3. Chlorobenzene (C₆H₅Cl) Ethyl chloride (C₂H₅Cl) Sodium metal (Na) in dry ether (solvent).
4. Sodium metal reacts with both chlorobenzene and ethyl chloride to generate reactive intermediates (aryl and alkyl sodium species). These intermediates couple together, forming a new carbon-carbon bond between the aromatic ring and the alkyl group.
5. Ethylbenzene (C₆H₅–C₂H₅) is formed where the ethyl group substitutes the chlorine on the benzene ring via the sodium-mediated coupling.
   \[\mathrm{C_6H_5Cl} + \mathrm{C_2H_5Cl} + 2 \mathrm{Na} \xrightarrow[\text{dry ether}]{\text{heat}} \mathrm{C_6H_5C_2H_5} + 2 \mathrm{NaCl}\]
6. Sodium facilitates the removal of chlorine from both aryl and alkyl halides and helps couple the two moieties.
7. This reaction provides a method for forming alkyl-substituted aromatic compounds from aryl halides and alkyl halides.