Aromatic Chemistry

• Benzene undergoes the mechanism...

  electrophilic substitution
• The types of electrophilic substitution that benzene undergoes are...

  Friedal Craft acylation and Nitration
• The conditions and catalyst for Friedal Craft acylation are...

  60 degrees

  AlCl3
• The equations for the formation and re-formation of the elctrophile in Freidal Craft acylation are...

  AlCl3 + CH3COCl -> AlCl4- + CH3CO+

  H+ + AlCl4- -> AlCl3 + HCl
• What is formed in Friedal Craft acylation?

  phyenyl ketones
• What are the catalysts and conditions for Nitration?

  conc HNO3 and conc H2SO4

  60 degreees
• Why can't the temperature for electrohpilic substitution of benzene be more that 60 degrees?

  there would be further substitutions
• What is formed during the nitration of benzene?

  phenyl nitrate
• What is the equation for the formation of the electrophile used in the nitration of benzene?

  HNO3 + H2SO4 -> NO2+ + H2O + H2SO4-
• What are phenyl nitrates used for?

  the formation of dyes
• What is formed by the reduction of benzene?

  amines
• What are the reagents for the reduciton of benzene?

  tin and conc HCl
• Why is methylbenzene more reactive than benzene?

  • alkyl induction from methyl group increases electron density in the delocalised ring
  • more attractive to electrophiles
• How do electronegative atoms (e.g. Cl2) effect the reactivity of benzene?

  • ring of delocalised electrons extends to include lone pair on the atom
  • the C-Cl bond is stronger
• Hydrogenation data of benzene is...

  • less exothermic than expected (more energy is needed to break delocalised electron attraction)
  • actually -360 rather than -208 as expected
• What 4 points proves that beneze isnt in the kekule structure?

  • hydrogenation data- less exo
  • bond length- all the same
  • shape- distorted vs planar hexagonal