Which of the following reactions does not form salicylic acid ?

Options

A. Permanganate oxidarion of o-cresol
B. Reimer-Tiemann carboxylation
C. Duff reaction
D. Kolbe-Schmidt reaction

Answer

To determine which reaction does not form salicylic acid, we will analyze each of the given reactions one by one.

### Step-by-Step Solution:

1. **Identify the Structure of Salicylic Acid**:
- Salicylic acid has the structure:
\[ \text{C}_6\text{H}_4(\text{OH})(\text{COOH}) \]
- It consists of a benzene ring with a hydroxyl group (–OH) and a carboxylic acid group (–COOH) attached to it.

2. **Analyze the First Reaction: Permanganate Oxidation of Ortho-Chrysol**:
- Ortho-chrysol has the structure:
\[ \text{C}_6\text{H}_4(\text{OH})(\text{CH}_3) \]
- When treated with potassium permanganate (KMnO4) in a basic medium (like NaOH), the methyl group (–CH3) is oxidized to a carboxylic acid (–COOH), resulting in salicylic acid.
- **Conclusion**: This reaction forms salicylic acid.

3. **Analyze the Second Reaction: Riemert-Ehmann Carboxylation**:
- In this reaction, phenol is treated with carbon tetrachloride (CCl4) and a base (like KOH or NaOH), followed by hydrolysis.
- This process leads to the formation of salicylic acid.
- **Conclusion**: This reaction also forms salicylic acid.

4. **Analyze the Third Reaction: Duff Reaction**:
- In the Duff reaction, phenol is treated with hexamethylene tetraamine (HMTA).
- This reaction converts phenol into salicylaldehyde (–CHO) instead of salicylic acid.
- **Conclusion**: This reaction does not form salicylic acid.

5. **Analyze the Fourth Reaction: Kolbe-Schmidt Reaction**:
- In the Kolbe-Schmidt reaction, phenol is treated with carbon dioxide (CO2) in the presence of a base (like NaOH), followed by hydrolysis.
- This reaction also leads to the formation of salicylic acid.
- **Conclusion**: This reaction forms salicylic acid.

### Final Answer:
The reaction that does not form salicylic acid is the **Duff reaction**.

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