6.1.4

• difference with benzene is that in order to get a similar reaction as alkenes between bromine + benzene you need a hot benzene + UV light but it is still a struggle

  • this is due to the pi system in benzene, making benzene very stable + spread out negative charge

  → so benzene is unwilling to undergo addition reactions as it would break stable ring

  • in alkene addition reactions occur across C=C bonds as an electrophile reacts with them to form stable alkanes
  • benzene prefers electrophilic substitution

  → electrophiles have a positive charge
• Friedel-Crafts

  scientist developed a technique for aromatic compound where H atom is substituted for an alkyl group

  • this is by breaking C-H bond and forming C-C bond

  → very difficult to add alkyl so you use Lewis Acids as a catalyst
• alkylation of benzene

  
• acylation