Acetaldehyde, also called ethanal, is the simplest aldehyde (CH3CHO).
It is a colorless, flammable liquid made by the catalytic
oxidation of ethanol. Acetaldehyde is an important
reagent used in the manufacture of dyes, plastics,
and many other organic chemicals. In the presence of acids it forms the
cyclic polymers paraldehyde (CH3CHO)3,
and metaldehyde (CH3CHO)4. The former is used as a
hypnotic, and the latter as a solid fuel for portable stoves and as a poison
for snails and slugs.