Ester Reactions: Acid-Catalyzed Hydrolysis: Videos & Practice Problems

Acid-catalyzed hydrolysis of esters is a chemical reaction where an ester is broken down into a carboxylic acid and an alcohol in the presence of water and an acid catalyst, typically H⁺. The reaction involves the ester bond being cleaved, with the carbonyl carbon gaining a hydroxyl group (–OH) to form a carboxylic acid, and the oxygen from the ester linkage acquiring a hydrogen atom to form an alcohol. This process is essential for understanding esterification and hydrolysis reactions in organic chemistry.

The products of acid-catalyzed hydrolysis of esters are a carboxylic acid and an alcohol. During the reaction, the ester bond is broken, and the carbonyl carbon of the ester gains a hydroxyl group (–OH), transforming into a carboxylic acid. Simultaneously, the oxygen from the ester linkage acquires a hydrogen atom, forming an alcohol. This reaction is facilitated by the presence of water and an acid catalyst, typically H⁺.

The acid catalyst, typically H⁺, functions by protonating the carbonyl oxygen of the ester, making the carbonyl carbon more electrophilic and susceptible to nucleophilic attack by water. This protonation step is crucial as it facilitates the cleavage of the ester bond. The acid catalyst also helps stabilize the transition state and intermediates during the reaction, ensuring the efficient conversion of the ester into a carboxylic acid and an alcohol.

Water is necessary in the acid-catalyzed hydrolysis of esters because it acts as the nucleophile that attacks the electrophilic carbonyl carbon of the ester. This attack leads to the cleavage of the ester bond. The water molecule provides the hydroxyl group (–OH) that attaches to the carbonyl carbon, forming a carboxylic acid, and the hydrogen atom that attaches to the oxygen from the ester linkage, forming an alcohol. Without water, the hydrolysis reaction cannot proceed.

The carbonyl carbon in the hydrolysis of esters plays a crucial role as the electrophilic center that is attacked by the nucleophile, which is water in this case. During the reaction, the carbonyl carbon is protonated by the acid catalyst, making it more susceptible to nucleophilic attack. Once attacked by water, the carbonyl carbon undergoes a series of transformations, ultimately gaining a hydroxyl group (–OH) and converting into a carboxylic acid. This step is essential for the cleavage of the ester bond and the formation of the reaction products.