Aromatic aldehydes may also be
prepared by oxidation of (i) methylbenzene with chromyl chloride or CrO3 in the
presence of acetic anhydride, (ii) formylation of arenes with carbon monoxide and
hydrochloric acid in the presence of anhydrous aluminium chloride, and (iii) cuprous
chloride or by hydrolysis of benzal chloride Ketones are prepared by oxidation of
secondary alcohols and hydration of alkynes Ketones are also prepared by reaction
of acyl chloride with dialkylcadmium A good method for the preparation of aromatic
ketones is the Friedel-Crafts acylation of aromatic hydrocarbons with acyl chlorides
or anhydrides