Arenes - Summary

  • benzene
  • energetic stability of benzene
  • substitution reactions
  • addition on halogens to benzene
  • phenols and their properties
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  • Created by: Harveen
  • Created on: 22-11-10 18:40

 

  • Arenes have considerable energetic stability because of the delocalised pi bonding electrons. Arenes require much more vigorous reaction conditions than alkenes to undergo addition reactions because of this extra stability.
  • Arene chemistry is dominated by electrpophilic substitution reactions that enable arenes to retain the delocalised pi electrons (ring). Hydrogen atoms on the benzene ring may be replaced by a variety of other atoms or groups including halogen atoms & nitro (-NO2) groups.
  • The variety of substituition reactions on benzene provides access to many useful compounds including medicines, dyes, explosives and polymers.
  • When the -OH group is joined directly to a benzene ring, the resulting alcohol is called a phenol.
  • Phenols are weakly acidic and form salts, called phenoxides, plus water on reaction with sodium hydroxide.
  • The reaction of sodium with phenol produces sodium phenoxide and hydrogen gas.
  • The -OH group enhances the reactivity of the benzene ring towards electrophiles. Bromine water is decolourised by phenol, producing a white precipitate of 2,4,6-tribromophenol
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Comments

Dave

Useful summary notes for a quick one over, thank you, four stars :)

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