Acetaldehyde - C2H4O

Acetaldehyde, ethanal, is a colourless, water-soluble, burnable fluid that has the chemical formula C2H4O and the structural formula CH3CHO. Acetaldehyde has a low boiling point at 21 °C.

It exists in alcohol, tobacco and food that has been produced by fermentation.

It is for example used as flavouring in soda. It also exists naturally in some fruit and fruit juices.

Acetaldehyde is irritating on skin and the respiratory system.


  • Molecular weight:

    44.05 g/mol

  • Gaseous phase:

    Gas density (at 20 °C): 0.784 g/cm3

  • Solid phase:

    Melting point: -123.37 °C

  • Liquid phase:

    Boiling point: -20.02 °C