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ASChemistryCIERevision Notes17. Carbonyl Compounds17.1 Aldehydes & KetonesReactions of Aldehydes & Ketones

Reactions of Aldehydes & Ketones (CIE AS Chemistry)

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Philippa Platt

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Reactions of Aldehydes & Ketones

Reduction of aldehyde & ketones

  • Aldehydes and ketones can be reduced by reducing agents such as NaBH4 or LiAlH4
  • Aldehydes are reduced to primary alcohols
  • Ketones are reduced to secondary alcohols

 

Reduction of ethanal and propanone

Hydroxy Compounds Reduction, downloadable AS & A Level Chemistry revision notes

Aldehydes are reduced to form primary alcohols, while ketones are reduced to to form secondary alcohols

Nucleophilic addition with HCN

  • Aldehydes and ketones can undergo nucleophilic addition with hydrogen cyanide, HCN
  • The cyanide ion, CN-, acts as a nucleophile and adds across the C-O bond
  • Aldehydes and ketones react with HCN, KCN as catalyst and heat to produce hydroxynitriles
    • Hydroxynitriles are nitriles containing a hydroxy, -OH, group

 

Nucleophilic addition of HCN to ethanal and propanone 

Carbonyl Compounds Nucleophilic Addition, downloadable AS & A Level Chemistry revision notes

The nucleophilic addition of HCN to aldehydes always forms a chiral hydroxy nitrile compound, while the nucleophilic addition of HCN to ketones may form a chiral hydroxy nitrile compound

Examiner Tip

The nucleophilic addition of HCN to an aldehyde or ketone increases the length of the carbon chain by one carbon atom!

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    Philippa Platt

    Author: Philippa Platt

    Expertise: Chemistry

    Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener.