its derivatives by strong oxidising agents such as KMnO gives benzoic acid. When chromylchloride is used as an oxidising agent, toluene gives benzaldehyde. This reaction is called Etard reaction . Acetic anhydride and CrO can also be used for this reaction.
+ CrO Cl CS CH (OCr(OH)Cl ) H O + CHO methylbenzene benzaldehyde XII U12-Carbonyl XII U12-Carbonyl - - - - Oxidation of toluene by chromic oxide gives benzylidine diacetate which on hydrolysis gives benzaldehyde. ) Gattermann – Koch reaction This reaction is a variant of Friedel – Crafts acylation reaction. In this method, reaction of carbon monoxide and HCl generate an intermediate which reacts like formyl chloride. CO, HCl AlCl / CuCl CHO ) Manufacture of benzaldehyde from toluene Side chain chlorination of toluene gives benzal chloride, which on hydrolysis gives benzaldehyde.
Toluene Cl / h υ CHCl Benzalchloride H O K CHO Benzaldehyde This is the commercial method for the manufacture of benzaldehye. D) Preparation of ketones ) Ketones can be prepared by the action of acid chloride with dialkyl cadmium. Example Cl + Cl C CH 2CH CH + CdCl Cd H C Dimethyl cadmium Acetone Acetyl chloride ) Preparation of phenyl ketones Friedel – Crafts acylation It is the best method for preparing alkyl aryl ketones or diaryl ketones. This reaction succeeds only with benzene and activated benzene derivatives.
XII U12-Carbonyl XII U12-Carbonyl - - - - Example Cl AlCl CO acetylchloride benzene acetophenone C H Cl AlCl CO C H benzoylchloride benzene benzophenone