Esters can be cleaved back into a carboxylic acid and an alcohol by reaction with water and a base. The reaction is called a saponification from the Latin sapo which means soap. The name comes from the fact that soap used to be made by the ester hydrolysis of fats. Due to the basic conditions a carboxylate ion is made rather than a carboxylic acid.
Step 1: Nucleophilic attack by hydroxide
Step 2: Leaving group removal
Step 3: Deprotonation
Prof. Steven Farmer (Sonoma State University)