Hydrolysis to carboxylic acid [basic]
Hydrolysis to carboxylic acid [basic] Definition:
Esters can be converted to carboxylic acids through treatment with strong base.
Hydrolysis to carboxylic acids [basic] Explained:
Esters can be hydrolyzed under acidic or basic conditions. These hydrolyses are nucleophilic substitution reactions that proceed by the addition-elimination mechanism.
Esters are hydrolyzed in aqueous base to form carboxylate anions and alcohols, this treatment employs sodium hydroxide. Carboxylic acids can be produced from carboxylic anions in a separated process by treatment with acid.
Basic hydrolysis of the ester is called saponification because this reaction produces soaps (Latin word sapo means soap). Treatment of fats and oils, which contain three ester groups, with a strong base, such as sodium hydroxide, the ester group hydrolyzed, giving glycerol and three sop molecules.
The mechanism of hydrolysis of esters in base consists of two parts:
The first part of the mechanism for this reaction has the usual two steps of the general mechanism for nucleophilic acyl substitution: addition of the nucleophile (hydroxyl group), followed by elimination of a leaving group (alkoxide ion). Although this is a poor leaving group reaction occurs because the tetrahedral intermediate is sufficiently high in energy that it can expel even a bad leaving group.
In the second part of the mechanism, the carboxylic acid does not survive under such strongly basic conditions. It is deprotonated to produce a carboxylic salt. This is an irreversible process and once the reaction is complete and the carboxylate anion is formed, it can be protonated with strong acid to form the neutral carboxylic acid.