Benzene

Benzene

1. Groups

   • Nitro=NO2
   • Alkyls=CnH2n+1 e.g Methyl CH3
   • Phenyl group when attached to bigger molecules ➡ C6H5
     • Phenol=OH
       • Phenol
     • Amine=NH2
   • Aldehyde=CHO
   • Carboxylic acid=COOH
   • Halogens
     • Chloro=Cl
     • Bromo=Br

2. Kekulé's model

   • Doesn't explain low reactivity
     • suggested rapid equilibrium
   • doesn't decolourise bromine water in electrophillic addition
   • alternate single double bonds= X
     • X-ray➡same intermedite length
   • Hydrogenation
     • Hydrogens added across double bond
       • ▪Benzene less energy= delocalised/resonance energy ▪benzene= more stable

3. Delocalised model

   • ▪Cyclic planar hexagonal ring ▪Trigonal planar around each C = 120' ▪4th p electron unbonded ▪p orbitals overlap on C's either side➡pi cloud of delocalised electrons above and below the ring

4. Reactions

   • Electrophillic substitution
   • Halogenation
   • Enter text here