Mendius Reaction and Gattermann Reaction

Mendius reaction and Gattermann reaction are important named reactions of organic chemistry. These reactions are commonly studied in Class 12, NEET, and JEE syllabi. Both reactions are used for the preparation of important organic compounds.

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1. Mendius Reaction

Mendius reaction is the reduction of nitriles to primary amines using sodium metal in alcohol. It is an important method for the preparation of aliphatic primary amines.

General Reaction

R–C≡N + 4[H] → R–CH₂–NH₂

Reagents Used

• Sodium metal (Na)
• Alcohol (ethanol or methanol)

Example

CH₃–CN + Na / C₂H₅OH → CH₃–CH₂–NH₂

Important Points

• Nitrile group is reduced to primary amine
• Carbon chain length increases by one carbon atom
• Sodium acts as a reducing agent
• Reaction proceeds through nascent hydrogen

Uses

• Preparation of primary aliphatic amines
• Used in organic synthesis

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2. Gattermann Reaction

Gattermann reaction is used for the introduction of aldehyde group into an aromatic ring. It is also known as a formylation reaction of aromatic compounds.

General Reaction

Ar–H + HCN + HCl → Ar–CHO

Catalysts Used

• Anhydrous aluminium chloride (AlCl₃)
• Cuprous chloride (CuCl)

Example

C₆H₆ + HCN + HCl → C₆H₅–CHO

In this reaction, benzene is converted into benzaldehyde.

Important Points

• Aldehyde (–CHO) group is introduced into aromatic ring
• Reaction mainly occurs at ortho and para positions
• Used for preparation of aromatic aldehydes

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Difference Between Gattermann and Gattermann–Koch Reaction

Gattermann Reaction	Gattermann–Koch Reaction
Uses HCN and HCl	Uses CO and HCl
Uses AlCl3 and CuCl as catalyst	Uses AlCl3 and CuCl as catalyst
Less commonly used	More commonly used

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One-Line Examination Answers

Mendius Reaction: Reduction of nitriles to primary amines using sodium metal in alcohol.

Gattermann Reaction: Formylation of aromatic compounds using HCN and HCl in presence of AlCl₃ and CuCl.

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Prepared for academic and examination purposes.