When a stream of ozonised oxygen is passed through a solution of an alkene, in organic solvent, an unstable addition cyclocompound, ozonide is formed which on reduction with zinc dust and water forms an aldehyde or a ketone or a mixture of both.
1. Formaldehyde :
Under these conditions ethylene gives formaldehyde.
2. Acetaldehyde :
Symmetrically disubstituted alkene like but-2-ene gives acetaldehyde.
3. Acetone :
Tetrasubshtwed alkene like 2,3-dimethyl but-2-ene gives acetone.
