A one-step procedure for the preparation of (E)-2-nonenal from commerc
ial castor oil by ozonolysis in acetic acid, followed by exposure of t
he resulting intermediate product to p-toluene sulfonic acid, is descr
ibed. The manufactured aldehyde is of high purity and the method, by v
irtue of being simple and using inexpensive raw material, has advantag
es over those reported in the literature.