3.2.4

Chlorination

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Chlorination

Chlorination is the first reaction mechanism that you need to learn. This mechanism involves free radicals.

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Overall reaction

  • Products:
    • With excess methane, chloromethane.
    • With excess chlorine, you get multiple reactions and end up with tetrachloromethane.
  • The reaction can be split up into three stages:
    • Initiation.
    • Propagation.
    • Termination.
  • This is characteristic of all free radical reactions.
Illustrative background for InitiationIllustrative background for Initiation ?? "content

Initiation

  • This step first generates the free radicals.
  • The balanced equation is:
    • Cl2light2ClCl_2 \xrightarrow[\text{}]{\text{light}} 2Cl\bullet
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Propagation

  • There are often multiple propagation steps.
  • These involve a free radical, and generate a new free radical.
  • Relevant equations are:
    • CH4+ClCH3+HClCH_4 + Cl\bullet \rightarrow CH_3\bullet+ HCl
    • CH3+Cl2CH3Cl+ClCH_3\bullet + Cl_2 \rightarrow CH_3Cl + Cl\bullet
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Termination

  • A termination step is one which involves two free radicals forming a covalent bond.
    • It is said to ‘consume’ free radicals.
  • It is the final step in the reaction.
  • Relevant equations are:
    • 2CH3C2H62CH_3\bullet \rightarrow C_2H_6
    • 2ClCl22Cl\bullet \rightarrow Cl_2
    • CH3+ClCH3ClCH_3\bullet + Cl\bullet \rightarrow CH_3Cl

Jump to other topics

1Physical Chemistry

1.1Atoms, Molecules & Stoichiometry

1.2Atomic Structure

1.3Chemical Bonding

1.4States of Matter

1.5Chemical Energetics

1.6Electrochemistry

1.7Equilibria

1.8Partition Coefficient

1.9Reaction Kinetics

2Inorganic Chemistry

3Organic Chemistry & Analysis

3.1Introduction to Organic Chemistry

3.2Hydrocarbons

3.3Halogen Derivatives

3.4Hydroxy Compounds

3.5Carbonyl Compounds

3.6Carboxylic Acids & Derivatives

3.7Nitrogen Compounds

3.8Polymerisation

3.9Analytical Techniques

3.10Organic Synthesis

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