Propionaldehyde or propanal is the organic compound with the formula CH3CH2CHO. It is the 3-carbon aldehyde. It is a colourless, flammable liquid with a slightly fruity odour. It is produced on a large scale industrially.

It should be used as a chemical intermediate only. It undergoes reactions typical for the low molecular weight aldehydes, which, because of the terminal carbonyl group, are very reactive. Contamination or the exposure to elevated temperatures may induce a hazardous polymerization.

Propionaldehyde is readily oxidized if in contact to oxygen and should therefore be stored under inert gases.



  • Intermediate for the chemical industry
  • For the manufacture of pharmaceuticals
  • Pesticides
  • Perfumes
  • Plastics