Chemical Properties

Chemical Properties . Hydrolysis We have already learnt that hydrolysis of esters gives alcohol and carboxylic acid. . Reaction with alcohol ( Transesterification) Esters of an alcohol can react with another alcohol in the presence of a mineral acid to give the ester of second alcohol. The interchange of alcohol portions of the esters is termed transesterification Ethyl acetate OC H + HOC H Ethyl alcohol H + OC H + C H OH Propyl acetate Propyl alcohol The reaction is generally used for the preparation of the esters of a higher alcohol from that of a lower alcohol. . Reaction with ammonia (Ammonolysis) Esters react slowly with ammonia to form amides and alcohol. Ethyl acetate OC H + H Ethyl alcohol NH + C H OH Acetamide NH XII U12-Carbonyl XII U12-Carbonyl - - - - . Claisen Condensation Esters containing at least one ∝ - hydrogen atom undergo self condensation in the presence of a strong base such as sodium ethoxide to form b - keto ester. Ethyl acetate OC H + H Ethyl alcohol C H ONa Ethyl aceto acetate Ethyl acetate OC H OC H + C H OH . Reaction with PCl Esters react with PCl to give a mixture of acyl and alkyl chloride Ethyl acetate OC H + PCl Ethyl chloride Cl + C H Cl + POCl Acetyl chloride Evaluate yourself Why is acid anhydride preferred to acyl chloride for carrying out acylation reactions ? . . Acid Amides Acid amides are derivatives of carboxylic acid in which the – OH part of carboxyl group has been replaced by – NH group. The general formula of amides are given as follows. R C NH Now, we shall focus our attention mainly on the study of chemistry of acetamide. Methods of Preparation . Ammonolysis of acid derivatives Acid amides are prepared by the action of