What is a Nitrile?
Nitrile is a compound having a −C≡N group. The organic compound with multiple nitrile groups is called cyano hydrocarbons, while the inorganic compound with nitrile group is called cyanide.
Nitrile compounds are used in making super glue, medical gloves and automation.
This section will discuss the conversion of Nitrile to Carboxylic Acid under various reaction conditions.
Table of Content
- Nitrile to Carboxylic Acid
- Acid Catalysed Nitrile Hydrolysis
- Base Catalysed Nitrile Hydrolysis
- Frequently Asked Questions – FAQs
Nitrile to Carboxylic Acid
Nitriles get hydrolysed with water to yield corresponding carboxylic acid or salt. The reaction between water and nitrile doesn’t occur easily. Nitrile is heated with dilute acid or alkali for reaction to occur. The end product will be a carboxylic acid, but its character may vary depending on the reaction conditions.
Amide is formed as an intermediate between an acid and nitrile. We can even isolate amide during the reaction.
CH3CN + H2O → CH3CONH2 → CH3COONH4 + H+ ⟶ CH3COOH
In the above reaction, Ethanenitrile on getting hydrolysed yields ethanamide followed by ammonium ethanoate.
Acid Catalysed Nitrile Hydrolysis
Nitrile Hydrolysis doesn’t occur efficiently; nitrile is hydrolysed under reflux with dilute hydrochloric acid for reaction to occur.
Example: Under acidic conditions, hydrolysis of ethanenitrile yields ethanamide followed by ethanoic acid.
CH3CN + 2H2O + HCl ⟶ CH3COOH + NH4Cl
In the absence of an acidic medium, ammonium ethanoate would have been formed in place of ethanoic acid. Ethanoate ions in ammonium ethanoate react with the hydrogen ion to form ethanoic acid. Hydrogen ions hang on ethanoic acid.
Base Catalysed Nitrile Hydrolysis
Nitrile Hydrolysis doesn’t occur efficiently; nitrile is hydrolysed under reflux with alkali for reaction to occur.
Example: Under basic conditions, hydrolysis of ethanenitrile yields ethanamide followed by sodium salt of ethanoic acid and ammonia gas, which can easily convert to ethanoic acid.
CH3CN + H2O + NaOH ⟶ CH3COONa– + NH3 + HCl ⟶ CH3COOH
The reaction between ammonium and hydroxide ions liberates ammonia gas during the reaction.
If ethanoic acid is the desired product, then acid catalysed nitrile hydrolysis is preferred over base catalysed nitrile hydrolysis.
Frequently Asked Questions on Nitrile to Carboxylic Acid
What is nitrile?
Nitrile is a compound having a −C≡N group. The organic compound with multiple nitrile groups is called cyano hydrocarbons, while the inorganic compound with nitrile group is called cyanide.
Nitrile compounds are used in making super glue, medical gloves and automation.
How can we convert nitrile into carboxylic acid?
Nitriles get hydrolysed with water to yield corresponding carboxylic acid or salt. Nitrile is heated with dilute acid or alkali for reaction to occur. The end product will be a carboxylic acid, but its character may vary depending on the reaction conditions.
Amide is formed as an intermediate between an acid and nitrile. We can even isolate amide during the reaction.
CH3CN + H2O → CH3CONH2 → CH3COONH4 + H+ ⟶ CH3COOH
What is acid catalysed nitrile hydrolysis?
When nitrile is hydrolysed under reflux with dilute hydrochloric acid, the reaction conditions are termed acid catalysed nitrile hydrolysis.
Example: Under acidic conditions, hydrolysis of ethanenitrile yields ethanamide followed by ethanoic acid.
CH3CN + 2H2O + HCl ⟶ CH3COOH + NH4Cl
What is base catalysed nitrile hydrolysis?
When nitrile is hydrolysed under reflux with a sodium hydroxide solution, the reaction conditions are termed base catalysed nitrile hydrolysis.
Example: Under basic conditions, hydrolysis of ethanenitrile yields ethanamide followed by sodium salt of ethanoic acid and ammonia gas.
CH3CN + H2O + NaOH ⟶ CH3COONa– + NH3 + HCl ⟶ CH3COOH
Why is acid catalysed nitrile hydrolysis preferred over base catalysed nitrile hydrolysis for free acid production?
If free acid is the desired product, acid catalysed nitrile hydrolysis is preferred over base catalysed.
In acidic media, ethanoate ions in the ammonium ethanoate react with the hydrogen ions liberated by hydrochloric acid to form ethanoic acid.
Example: Under acidic conditions, hydrolysis of ethanenitrile yields ethanamide followed by ethanoic acid.
CH3CN + 2H2O + HCl ⟶ CH3COOH + NH4Cl
While under basic conditions, hydrolysis of ethanenitrile yields ethanamide followed by sodium salt of ethanoic acid and ammonia gas.
CH3CN + H2O + NaOH ⟶ CH3COONa– + NH3
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