alcohols

• alcohol = homologous series with a functional hydroxyl group (OH)
• Alcohols are classified by the number of alkyl groups bonded

  directly to the hydroxyl bearing carbon.

  • Primary – no or 1 alkyl group.
  • Secondary – 2 alkyl groups.
  • Tertiary – 3 alkyl groups.
• alcohols are liquid at room temp due to the london forces present
• adding branches to an alcohol will decrease the boiling point because there are less points of contact and the london forces are weaker - this requires less energy to overcome
• alcohols are miscible - form hydrogen bonds with water
• reaction of alcohols -combustion

  • complete combustion = carbon dioxide and water produced
  • incomplete combustion = carbon / carbon monoxide and water produced
• reaction of alcohols - oxidation

  • oxidising agent and K2Cr2O7 catalyst
  • primary alcohols = distil to form aldehydes and reflux to form carboxylic acids
  • secondary alcohols = reflux to form ketones
  • tertiary alcohols = resist oxidation
• reactions of alcohols - substitution

  • forms haloakanes with halide ions in the presence of an acid e.g. NaBr and H2SO4
  • the hydroxyl group is replaced with the halogen
  • Na + is a spectator ion
• reactions of alcohols - elimination

  • forms alkenes in the presence of hot concentrated H2SO4
  • water molecule is eliminated