Halogenalkanes

• Boiling points of haloalkanes increase down the group.
• The strength of the intermolecular forces increase down the group as the number of electrons increase, so there are stronger van der waals forces.
• Haloalkanes have a polar bond and are attacked by nucleophiles.
• A nucleophile is an electron pair donor.
• Conditions for haloalkanes reacting with hydroxide ions:

  • Warm aqueous sodium hydroxide
  • Carried out under reflux.
• Conditions for haloalkanes reacting with cyanide ions:

  • Warm ethanoic potassium cyanide
  • Carried out under reflux
• Conditions for haloalkanes reacting with ammonia:

  • Heat with ethanolic ammonia
  • Must have excess ammonia
• Haloalkanes become more reactive as you go down the group
• The bond strength determines the reacitivity NOT bond polarity
• C-I has the lowest bond enthalpy and thus is the most reactive
• Conditions of reacting haloalkanes with hydroxide ions (elimination)

  • Warm ethanolic sodium hydroxide (dissolved in ethanol)
  • Carried out under reflux
• When reacting NaOH with a haloalkane, we can make:

  • An alkene using ethanol as a solvent
  • An alcohol using water as a solvent
• CFCs break down ozone (O3) in the atmosphere
• CFCs are broken down by UV radiation in the atmosphere.