chem benzene

alkenes vs benzene similarities

• both have sigma bonds between cc and ch

• both have pi systems made by sideways overlapping of p orbitals

• both have double bonds

• both undergo addition

alkenes vs benzene differences

• in benzene the electrons are delocalised

• in alkenes the electrons are delocalised

• in benzene pi system covers all 6 carbons

• in benzene pi system doesn'tcover all 6 carbons

benzene vs alkene reactions

• both react with electrophiles as they have regions of high electron density

• both undergo addition

• only alkenes will undergo addition

• only benzene will undergo substitution

test for halogens

• reflux with NaOH

• neutralise with HNO3

• add silver nitrate

• neutralise with NaOH

• reflux with HNO3

catalyst in nitration

• concentrated H2SO4

• anhydrous AlCl3

• halogenoalkane

• concentrated nitric acid

catalyst in halogenation

• concentrated H2SO4

• anhydrous AlCl3

• halogenoalkane

• concentrated nitric acid

catalyst in alkylation

• concentrated H2SO4

• anhydrous AlCl3

• halogenoalkane

• concentrated nitric acid

what is meant by resonance energy in benzene?

• Stabilization energy from delocalization of pi electrons
• Energy released when benzene undergoes a chemical reaction
• Energy required to break the pi bonds in benzene
• Energy released during the formation of benzene

nitration conditions

• 50 C

• conc h2so4 + HNO4

• room temp

• AlCl3

• halogenoalkane

alkylation conditions

• 50 C

• conc h2so4 + HNO4

• room temp

• AlCl3

• halogenoalkane