Propionaldehyde


 * ''Note that propanol is a different compound.

Propionaldehyde is the organic compound with the formula CH3CH2CHO. It is the only 3-carbon aldehyde and is a structural isomer of acetone. It is a colourless liquid with a slightly irritating, fruity odour.

Propionaldehyde is mainly produced through the hydroformylation, by combining synthesis gas (carbon monoxide and hydrogen) with ethylene using a metal catalyst:
 * CO + H2 + C2H4 → CH3CH2CHO

Uses
It is principally used to make trimethylolethane through a condensation reaction with methanol; this process is important in the production of alkyd resins.

Condensation of propionaldehyde with tert-butylamine gives CH3CH2CH=N-t-Bu, a useful three-carbon building block in organic synthesis. Deprotonation of this imine with LDA affords CH3CHLi2CH=N-t-Bu, which in turn condenses with aldehydes.