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.
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
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
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 |
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.
Prepared for academic and examination purposes.
