3.8.5

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

1Structure - Models of the Particulate of Matter

2Structure - Models of Bonding & Structure

3Structure - Classification of Matter

3.1The Periodic Table: Classification of Elements

3.2Periodic Trends

3.3Group 1 Alkali Metals

3.4Halogens

3.5Noble gases, group 18

3.6Functional Groups: Classification of Organic

3.7Functional Group Chemistry

3.8Alkanes

3.9Alcohols

3.10Halogenoalkanes

4Reactivity - What Drives Chemical Reaction?

5Reactivity - How Much, How Fast & How Far?

6Reactivity - The Mechanisms of Chemical Change

7Measurement, Data Processing & Analysis

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