Aldehydes and Ketones

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• Aldehydes and Ketones
• The carbonyl group
• Aldehydes have at least one hydrogen attached to
  the carbonyl group.
• Ketones have two carbons attached to the carbonyl
  group.

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• Naming Aldehydes
• Find the longest carbon chain that contains the
  aldehyde group.
• Change ending of the root alkane name by dropping
  e and adding al.
• All other branches and groups are named and
  located using standard IUPAC system.

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Butanal
2-ethyl butanal
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• Naming Ketones
• Find the longest chain that contains CO.
• Using the root alkane name, drop the e ending
  and change to one.
• Number the longest carbon chain so the CO group
  has the lowest number.
• Name and number other substituents as before.

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• Physical Properties.

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• Physical Properties, cont.
• Because of the polarity of the CO group, these
  groups can interact, but the attraction is not as
  strong as hydrogen bonding.
• This makes the boiling point of aldehydes and
  ketones higher than alkanes, but lower than
  alcohols.

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• Physical Properties, cont.
• The CO group can hydrogen bond with water
  molecules.

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• Reactions, cont.
• The addition of H2 in the presence of catalysts.

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• Examples

(propanone)
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• Aldehyde and Ketone Reactions
• Recall the oxidation of alcohols to produce
  aldehydes and ketones.

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• REACTIONS
• The ease with which aldehydes are oxidized allows
  us to test for the presence of aldehydes with
  Tollens reagent or Benedicts reagent.
• In general, ketones fail to react with these
  reagents.

From left to right, three test tubes containing
potassium dichromate (K2Cr2O7), acetone, and
benzaldehyde.
After the addition of equal amounts of K2Cr2O7,
the acetone remains unreacted, whereas the
benzaldehyde is oxidized.
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FORMALDEHYDE
Simplest Aldehyde IUPAC Name Methanal Gas at
Room Temp. Embalming Fluid
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automobile windshield washer fluid, gas line
antifreeze, copy machine fluid, fuel for small
stoves, paint strippers
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ACETONE
Simplest Ketone Airplane glue nail polish
remover varnishes IUPAC Name
Propanone Dissolves nonpolar substances
soluble In water
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Hormones
Testosterone Anabolic Steroid
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Testosterone
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(Provera)