7.5.4 Aromatic Amine Formation

• Phenylamine is an organic compound consisting of a benzene ring and an amine (NH₂) functional group
  • Phenylamine is sometimes known as aminobenzene and aniline
• Nitrobenzene, C₆H₅NO₂, can be reduced to phenylamine, C₆H₅NH₂, according to the following two-stage reaction:

The two-stage reduction reaction of nitrobenzene to phenylamine

Stage 1 - Reduction of nitrobenzene

• Nitrobenzene, C₆H₅NO₂, is reacted with tin, Sn, and concentrated hydrochloric acid, HCl
  • Tin and hydrochloric acid act as reducing agents
• The reaction mixture is heated under reflux in a boiling water bath
• The phenylammonium ions, C₆H₅NH₃⁺, are protonated due to the acidic conditions

Stage 2 - Formation of phenylamine

• • The phenylammonium ions, C₆H₅NH₃⁺, are deprotonated by the addition of excess sodium hydroxide solution, NaOH (aq)