Question

How is the following conversion carried out?

Chlorobenzene to benzylamine

Answer 1

The conversion of chlorobenzene to benzylamine can be carried out through a multistep reaction involving:

1. Chlorobenzene to Benzyl Chloride: First, chlorobenzene (C₆H₅Cl) undergoes a side-chain chlorination (chloromethylation) in the presence of light or a radical initiator to form benzyl chloride (C₆H₅CH₂Cl).
   \[\mathrm{C}_6\mathrm{H}_5\mathrm{Cl} \xrightarrow{Cl_2, h\nu} \mathrm{C}_6\mathrm{H}_5\mathrm{CH}_2\mathrm{Cl}\]
2. Benzyl Chloride to Benzylamine: Benzyl chloride is then treated with ammonia (NH₃), which undergoes nucleophilic substitution to replace the chlorine with an amino group, forming benzylamine (C₆H₅CH₂NH₂).
   \[\mathrm{C}_6\mathrm{H}_5\mathrm{CH}_2\mathrm{Cl} + 2, \mathrm{NH}_3 \rightarrow \mathrm{C}_6\mathrm{H}_5\mathrm{CH}_2\mathrm{NH}_2 + \mathrm{NH}_4\mathrm{Cl}\]

Here, excess ammonia is used to favor the formation of benzylamine and to neutralize the HCl formed, producing ammonium chloride.