Aldehydes

• Aldehydes


  Organic compounds that contain the carbonyl group, with one organic group and one H attached to the carbon
• Ketones


  Organic compounds that contain the carbonyl group, with two organic groups attached to the carbon
• Formation of aldehydes and ketones

  From the oxidation of alcohols
• Oxidation of primary alcohols


  Gives aldehydes
• Uses of aldehydes


  • Formaldehyde solution (Formalin) used for embalming
  • Formaldehyde used in building insulation and adhesive resins
  • Acetaldehyde is an eye irritant in smog
  • Pyridoxal phosphate is an aldehyde coenzyme involved in metabolic reactions
• Nomenclature of aldehydes


  • Replace the terminal -e of the corresponding alkane name with -al
  • The carbonyl carbon gets the priority in numbering the longest chain
  • The parent chain must contain the -CHO group
  • For cyclic aldehydes, the suffix -carbaldehyde is used
  • When both double bonds and carbonyl groups are present, the -en suffix follows the parent chain and the -al suffix follows the -en suffix
• Examples of aldehyde names

  • Formaldehyde (Methanal)
  • Acetaldehyde (Ethanal)
  • Propanaldehyde (Propanal)
  • Benzaldehyde (Benzenecarbaldehyde)
• Nomenclature of ketones


  • The IUPAC name gives the suffix -one
  • The carbonyl group takes precedence over other substituents in numbering the parent chain
  • When both double bonds and carbonyl groups are present, the -en suffix follows the parent chain and the -one suffix follows the -en suffix
  • If there is a choice in numbering, the parent chain is numbered to give the substituents the lowest number at the first point of difference
• Examples of ketone names

  • Ethyl Propyl Ketone (3-Hexanone)
  • Dimethyl Ketone or Acetone (Propanone)
• Naming aldehydes and ketones in the same molecule

  Aldehydes have higher priority than ketones, so the molecule is named as an aldehyde and the ketone is named as an "oxo" substituent
• Naming dialdehydes and diketones

  • For dialdehydes, the location numbers for both carbonyls are omitted
  • For diketones, both carbonyls require a location number
• Naming cyclic ketones and diketones

  • In cyclic ketones, the carbonyl group is assigned location position #1, and this number is not included in the name
  • With cycloalkanes containing two ketones, both carbonyls need to be given location numbers, and the suffix -dione is added
• Naming carbonyls and hydroxyls in the same molecule

  The carbonyl is given the lowest possible location number and the appropriate nomenclature suffix is included, while the OH is named as a hydroxyl substituent
• Naming carbonyls and alkenes in the same molecule

  The order is: (Location number of the alkene)-(Prefix name for the longest carbon chain minus the -ane ending)-(an -en ending)-(the location number of the carbonyl if a ketone is present)-(either an -one or an -anal ending)