Aromatic synthesis

• To turn benzene into nitrobenzene:

  • Reagent: Concentrated nitric acid and sulfuric acid- this is used to form the nitronium (NO2) electrophile
  • Nitric acid acts as a base as it accepts an electron from sulfuric acid

  $H_2SO_4 +$$HNO_3 \rightarrow 2HSO_4^- +$$^+$$NO_2 +$$H_3O^+$

  • Conditions: Above 60C
  • Type of reaction: electrophilic substitution

  
• Phenylamine groups can gain alkyl groups by nucleophilic substitution to form a secondary amine

  Conditions: Heated under reflux in a sealed container, in an ethanolic and water solution

  Reagent: Halogenoalkane

  
• To turn nitrobenzene into phenylamine:

  • Reagents: Tin and dilute hydrochloric acid catalyst OR hydrogen gas and a nickel catalyst
  • Sodium borohydride (NaBH4) or lithium aluminium hydride (LiAlH4) aren't used as they are too strong, and so they can disrupt the benzene ring.
  • Conditions: Mixture is heated
  • Name of reaction: Reduction

  
• To turn phenylamine into a secondary amide:

  • Reagents: Acyl chloride and phenylamine
  • Conditions: Room temperature
  • Name of reaction: Nucleophilic addition-elimination

  The reaction is the same as if 2 aliphatic groups react

  The molecule below would be called ethyl phenylamide

  
• To turn benzene into a phenyl ketone:

  • Reagents: Acyl chloride/acid anhydride in the presence of an anhydrous aluminium chloride catalyst

  Formation of electrophile:

  $AlCl_3+$$CH_3COCl \rightarrow CH_3CO^+$$+$$[AlCl_4]^-$

  • Conditions: Heat under reflux at 50C
  • Name of reaction: Electrophilic substitution