Mechanisms

Free Radical Substitution
1. Initiation
  1. UV light or +300C causes the covalent bond to break (fission).
    1. Hetrolytic Fission is unequal splitting of the electrons due to 2 different elements ( EG; H-Cl )
    2. Homolytic Fission is equal splitting of the electrons due to 2 identical elements ( EG: Cl-Cl )
  2. This forms 2 Radicals
  3. After initiation the reaction doesn't require any more energy input
2. Propagation
  1. In this case, the Chlorine Radical reacts with the methane,
  2. Forming HCl and a Methyl Radical
  3. Which then splits another Chlorine Molecule into 2 Radicals
3. Termination
  1. This is when 2 Radicals bond to form a compound or molecule only
  2. No new radicals are formed
4. This reaction can produce Haloalkanes
Elimination
1. Conditions needed:
  1. High Temperatures
  2. Concentrated Hydroxide Ions
  3. Ethanol as the solvent
2. This reaction causes Haloalkanes to turn into a Water molecule, a Halogen Ion and an Alkene
Electrophilic Addition
1. Can change Alkenes to Haloalkanes
2. An Electrophile is a species than can accept a pair of electrons
3. The Pi bond is broken when the electrophile gets close to it
4. A Di-Halogen Alkane is formed is a Halogen molecule is the electrophile
Nucleophilic Substitution
1. A Nucleophile is a species that is attracted to an electron defiecient centre, where it donates a pair of electrons to form a dative bond
2. Conditions needed:
  1. warm temperatures
  2. Aqueous Nucleophile ions
  3. Dilute Solutions
3. Hydroxide ions and Haloalkanes form Alcohols
4. Cyanide Ions and Haloalkanes form Nitrilles
5. Excess Ammonia and Haloalkanes form Amines

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	Created by Daniel Scutt over 9 years ago