Esterification vs. Saponification

Main Difference

The main difference between the Esterification and the Saponification is that Esterification is responsible for the formation of an ester from an alcohol and a carboxylic acid, whereas Saponification is responsible for the breakdown of esters back into the alcohol and carboxylic acid.

Difference Between Esterification and Saponification

Comparison Chart

Esterification vs. Saponification

Esters are referred to as the organic compounds, which are basically made up of H, C, and O atoms. The presence of the –COOR group shows that a specific molecule is an ester. Because of the presence of oxygen atoms, esters become polar compounds. They are also involved in the formation of hydrogen bonds with a lot of other compounds.

An ester came into existence when a reaction occurs between a carboxylic acid and an alcohol, and a catalyst is also used during its formation which is basically an acid catalyst. This type of formation is called esterification. The process, which is opposite to the esterification is referred to as saponification.

The process of esterification takes place in the presence of a catalyst which is responsible for reducing the activation energy hurdle of the reaction. This catalyst is usually an acid catalyst. Saponification, on the other hand, takes place in an aqueous medium, where the presence of a base is also essential. Because of the presence of the basic conditions of the medium, the carboxylate anion is considered more stable than the carboxylic acid form. The carboxylate ion gets detached from the ester because of this reason. The reaction mixture must be heated because to cleave the C-OH bond of the carboxylic acid to remove the –OH group.

The esterification process needs energy. Conversely, saponification has no energy barrier, and thus, it can take place without heat energy. In this reaction, the water molecules in the aqueous medium offer H⁺ ions for the formation of alcohol, and the base offers OH^– ions which are required for the formation of carboxylic acid.

What is Esterification?

Esterification is that process which is responsible for the formation of an ester from an alcohol and a carboxylic acid. The reaction also needs a catalyst to decrease the activation energy problem of the reaction, and the catalyst must be an acid catalyst. This process needs energy.

In order to eliminate the –OH group, the reaction mixture requires heat to cleave the C-OH bond of carboxylic acid. The reaction takes place when the proton of the –OH group of alcohol and the –OH group of the carboxylic acid is removed. Then, the alcoholic nucleophile and the carboxylic cation react with each other and form the ester.

The by-products of this reaction are the water molecules. The proton which we had removed from the alcohol reacts with the –OH group, which in turn was removed from the carboxylic acid, hence form a water molecule.

We can obtain pure ester by the addition of a dehydrating agent. An excess of alcohol is added to obtain a high yield of ester. We can also use a dehydrating agent that can eliminate the water which was produced in this reaction. We can also use other methods to remove the water like distillation.

What is Saponification?

Saponification is that process which is responsible for the breakdown of esters back into the alcohol and carboxylic acid. The reactants which are used to carry out this process are the carboxylic acid and an alcohol. The catalyst which is used in this type of process is a base. Energy is not required by the process of saponification.

In this process, the carbon atom of the –COO- bond in the ester is attacked by the OH- of the base. Because of the presence of two oxygen atoms, the two sides of the carbon atom are partially positively charged. Due to this reason, it is considered an easy goal for a nucleophile. After that, a bond is made with the carbon atom by the OH group. Then in order to become stable, a rearrangement takes place. This is the point at which the –OR group from the alcohol gets free, which is, in turn, responsible for making the carboxylic acid and is considered as the leaving group of this reaction.

The consequential carboxylic acid is deprotonated because the carboxylate ion is considered more stable in the basic medium. The removed proton is reserved by the –OR group to form alcohol.

Conclusion

The above discussion summarizes that saponification is a process that is opposite to the esterification. Esterification is involved in ester synthesis, whereas, saponification is the breakdown of the ester bond. The former needs energy to accomplish while no energy is required for the latter.