Difference Between Saponification and Neutralization

Main Difference – Saponification vs Neutralization

Saponification and neutralization are very important chemical reactions that are used in laboratory scale as well as industrial scale. Saponification is generally the formation of soap in the form of a suspension. This occurs due to the cleavage of a triglyceride into glycerol and fatty acids. Neutralization is the formation of a neutral medium after a chemical reaction has taken place. This can be observed mainly in acid-base reactions. Acids are capable of releasing H+ ions and bases are capable of releasing OH ions. When all H+ ions released from acid react with all OH ions released by the base, it is said that the medium has been neutralized. The main difference between saponification and neutralization is that saponification includes cleavage of an ester into alcohol and carboxylate ion whereas neutralization includes the formation of a neutral medium after the chemical reaction.

Key Areas Covered

1. What is Saponification
     – Definition, Mechanism, Salting Out
2. What is Neutralization
     – Definition, Different Types
3. What is the Difference Between Saponification and Neutralization
     – Comparison of Key Differences

Key Terms: Basicity, Carboxylic Acid, Ester, Exothermic, Fatty Acids, Glycerol, Potassium Hydroxide, Saponification, Soap, Triglycerides 

Difference Between Saponification and Neutralization - Comparison Summary

What is Saponification

Saponification is a process by which triglycerides react with sodium or potassium hydroxide to produce glycerol and a fatty acid salt called ‘soap’. Saponification includes the cleavage of an ester into carboxylic acid and alcohol using NaOH or KOH in the presence of water. Here, due to the basicity of the medium, carboxylate ion is produced instead of carboxylic acid.

A triglyceride is an ester that is derived from the reaction between a glycerol and fatty acids. Here, one glycerol molecule is combined with three fatty acid molecules. Each fatty acid has a carboxylic acid group. Glycerol molecule has three hydroxyl groups (-OH). Hence, three fatty acids can combine with these three hydroxyl groups forming the ester. In saponification, three fatty acids separate from the glycerol.

The mechanism of saponification includes the following steps:

  1. Nucleophile attack
  2. Leaving group removal
  3. Deprotonation
Main Difference - Saponification vs Neutralization

Figure 1: Mechanism of Saponification

In general, the chemical reaction between any fat and NaOH is saponification. The reaction is exothermic, in which heat is liberated to the surrounding. When soap is formed via saponification, it remains as a suspension. Then soap can be separated via salting out soap (formation of solid soap from suspension by adding common salt to the suspension).

What is Neutralization

A neutralization reaction is a chemical reaction between an acid and a base which produces a neutral solution. A neutral solution will always have the pH 7. This reaction involves the combination of H+ ions and OH ions to form water molecules.

If the final pH of an acid and base reaction mixture is 7, that means equal amounts of H+ and OH ions have reacted here (in order to form a water molecule, one H+ ion and one OH ions are required). The reacted acids and bases can be either strong or weak. The reactions vary depending on this fact.

Strong Acid-Strong Base Neutralization

  • Strong acids and strong bases are completely dissociated into ions in aqueous medium. Hence they release all possible H+ and OH ions into the medium.

Weak Acid-Weak Base Neutralization

  • This type of reaction does not give complete neutralization because weak acids and weak bases do not completely dissociate into their ions. Hence, a weak acid cannot be neutralized by a weak base and vice versa.

Weak Acid-Strong Base Neutralization

  • The neutralization of a weak acid with a strong base gives the medium a pH that is higher than 7.

Strong Acid-Weak Base Neutralization

  • The neutralization of a strong acid with a weak base results in a low pH than 7.
    Difference Between Saponification and Neutralization

    Figure 2: Performing an Acid-Base Reaction

Difference Between Saponification and Neutralization

Definition

Saponification: Saponification is a process by which triglycerides react with sodium or potassium hydroxide to produce glycerol and a fatty acid salt called ‘soap’.

Neutralization: A neutralization reaction is a chemical reaction between an acid and a base which produces a neutral solution (pH= 7).

Principle

Saponification: Saponification includes the cleavage of an ester into alcohol and carboxylate ion.

Neutralization: Neutralization includes the formation of a neutral medium after the chemical reaction.

End Products

Saponification: Saponification gives glycerol and a fatty acid salt (soap).

Neutralization: Neutralization gives a salt and water.

Chemical Reaction

Saponification: Saponification includes the reaction between an ester and sodium or potassium hydroxide in the presence of water.

Neutralization: Neutralization includes the reaction between an acid (strong or weak) and a base (strong or weak).

End Result

Saponification: Saponification forms soap as a suspension which can be separated via salting out of soap.

Neutralization: Neutralization forms a medium with pH 7.

Conclusion

Saponification is basically the formation of soap. This involves the cleavage of an ester into alcohol and carboxylic acid (in a basic medium, carboxylate ion is formed). Neutralization, on the other hand, is the formation of a neutral medium after the reaction between an acid and a base. The main difference between saponification and neutralization is that saponification includes cleavage of an ester into alcohol and carboxylate ion whereas neutralization includes the formation of a neutral medium after the chemical reaction.

Reference:

1. Helmenstine, Anne Marie. “Saponification Definition and Reaction.” ThoughtCo, Oct. 3, 2017, Available here.
2. Libretexts. “Saponification.” Chemistry LibreTexts, Libretexts, 21 July 2016, Available here.
3. Helmenstine, Anne Marie. “Neutralization Definition.” ThoughtCo, Apr. 26, 2016, Available here.

Image Courtesy:

1. “Wikipedia ester hydrolysis.” By Chem540grp5f08 – Own work (Public Domain) via Commons Wikimedia
2. “Titration” By Jfreyre~commonswiki assumed- Own work assumed (based on copyright claims) (CC BY-SA 2.5) via Commons Wikimedia 

About the Author: Madhusha

Madhusha is a BSc (Hons) graduate in the field of Biological Sciences and is currently pursuing for her Masters in Industrial and Environmental Chemistry. Her interest areas for writing and research include Biochemistry and Environmental Chemistry.

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