Question

Give the methods of preparation of aldehydes and ketones.

Answer 1

Aldehydes are prepared by

a. Dehydrogenation of primary alcohols 

b. Controlled oxidation of primary alcohols. 

c. Controlled and selective reduction of acylhalides 

Aromatic aldehydes can be prepared by

a. Oxidation of toluene with chromyl chloride or CrO₃ in the presence of acetic anhydride. 

b. Formylation of arenes with carbon monoxide and Hydrochloric acid in the presence of anhydrous aluminium chloride / Cuprous chloride. 

c. Hydrolysis of benzal chloride. 

Ketones are prepared by

a. oxidation of secondary alcohols 

b. Hydration of alkenes 

c. Reaction acyl chlorides with dialkyl cadmium 

d. By Friedel Crafts reaction