1.5 Aldehydes & Ketones (Carbonyl Group)

Carbonyl Group

• Aldehydes: have the carbonyl group at the end of the molecule.
  • Naming: use the alkane name, drop the “e” and add an “al” suffix
  • Ex:
  • Methane – methanal (formaldehyde)
  • Ethane – ethanal (acetolaldehyde)
• Ketones: have the carbonyl group in the middle of the chain.
  • Naming: use the alkane name, drop the “e” and ad an “one” suffix
  • Ex: propane – propanone

Properties of Aldehydes and Ketones

• Aldehydes and Ketones contain the C=O group, which is polar and allows these molecules to be soluble in water (smaller molecules);
  • and the carbon chains allow them to be soluble in nonpolar molecules
• Since they do not have the –OH group, they are less soluble in water than alcohols, and have a lower boiling point.