AQA AS Chemistry

Revision Notes

3.5.5 Elimination Reactions of Alcohols

Elimination Reactions

Elimination Reaction of Alcohols

  • Alcohols can also undergo dehydration to form alkenes
    • This is an example of an elimination reaction
    • Elimination reactions involve a small molecule leaving the parent molecule as a byproduct
    • In this case, the small molecule is a water molecule
    • The water molecule is formed from the -OH group and a hydrogen atom from the adjacent carbon atom
  • Alcohol vapour is passed over a hot catalyst of aluminium oxide (Al2O3) powder or pieces of porous pot
    • Excess hot, concentrated sulfuric acid or phosphoric acid is used as a catalyst

Hydroxy Compounds Dehydration of Alcohols, downloadable AS & A Level Chemistry revision notes

Dehydration of ethanol using aluminium oxide as a catalyst forms ethene gas, which can be collected over water

  • The reaction and mechanism for the dehydration of propan-1-ol is shown below

Dehydration of propan-1-ol mechanism

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