Question

Discuss the aromatic nucleophilic substitutions reaction of chlorobenzene.

Answer 1

The halogen of haloarenes can be substituted by OH^–, NH₂^– or CN^– with appropriate nucleophilic reagents at high temperature and pressure.

1. Chlorobenzene reacts with ammonium at 250 and at 50 atm to give aniline.
   \[\ce{\underset{\text{Chlorobenzene}}{C6H5Cl + 2NH3} ->[250°C][50 atm]\underset{\text{Aniline}}{C6H5NH2} + NH4Cl}\]
2. Chlorobenzcne reacts with CuCN in presence of pyridine at 250 to give phenyl cyanide.
   \[\ce{\underset{\text{Chlorobenzene}}{C6H5Cl + CuCN} ->[250°C][Pyridine]\underset{\text{Phenyl cyanide}}{C6H5CN + CuCl}}\]
3. Dows process:
   \[\ce{\underset{\text{Chlorobenzene}}{C6H5Cl + NaOH} ->[350°C][300 atm]\underset{\text{Phenol}}{C6H5OH} + CuCl}\]