|Class 12 Chemistry Aldehydes Ketones Acids||Methods for preparing only aldehydes|
Methods for preparing only aldehydes
From acid chlorides - Rosenmund reaction
Drawback – Formaldehyde can’t be prepard by this method : formyl chloride H – COCl is unstable .Aldehydes can be further reduced to alcohol. So, in order to stop it at aldehyde stage we have to poison it.
2.From reduction of alkyl cyanides – known as Stephen’s reduction (use of SnCl2)
This can also be occur in presence of other reducing agent like – DIBAL. (Disobutyl aluminiun hydride ).It is used for long chain nitrils.
2.Oxidation reaction – from hydrocarbons