The principal reaction of an ester is a hydrolysis. A hydrolysis reaction is defined as a decomposition with water. An ester can be readily hydrolysed to a carboxylic acid and an alcohol. The decomposition of an ester by water is quite a slow reaction and is best catalysed by either NaOH or HCl. Alkaline hydrolysis is much faster than acid hydrolysis; alkaline hydrolysis also gives a much higher yield. The products of hydrolysis differ slightly depending on whether acidic or alkaline conditions are used.
Acid hydrolysis is a reversible reaction and never goes to completion. A catalyst of HCl or NaOH is used.
Under alkaline conditions, the sodium salt of the carboxylic acid is formed. This is very much as expected as the carboxylic acid that first forms is neutralised by simply adding dilute HCl.
Hydrolysis of naturally occurring esters
Author: Adam Hughes (document modification date: 18th May 2003)©