The reagent used for protection of amino group during the nitration of aniline is

Options

A. `SOCl_(2)//`Pyridine
B. `PCl_(5)`
C. Acetic acid
D. Acetic anhydride

Answer

To solve the question regarding the reagent used for the protection of the amino group during the nitration of aniline, we can follow these steps:

### Step 1: Understanding the Problem
Aniline (C6H5NH2) contains an amino group (-NH2) that is highly activating towards electrophilic substitution reactions, such as nitration. However, this high reactivity can lead to unwanted oxidative products if not controlled.

**Hint:** Identify the nature of the amino group and its effects on reactivity.

### Step 2: Protecting the Amino Group
To prevent the amino group from reacting during the nitration process, we need to protect it. One common method of protection involves converting the amino group into an acetamide group by reacting it with an acid derivative.

**Hint:** Consider common acid derivatives that can react with amino groups.

### Step 3: Choosing the Right Reagent
In this case, acetic anhydride (CH3C(O)O)2 is a suitable reagent for this purpose. When aniline reacts with acetic anhydride, it forms N-acetylaniline (C6H5NHCOCH3), which is less reactive than aniline itself.

**Hint:** Think about how the structure of the product affects its reactivity.

### Step 4: Performing Nitration
Once the amino group is protected as N-acetylaniline, the nitration can proceed without the risk of oxidative products. The nitration will predominantly occur at the ortho position due to the directing effects of the acetyl group.

**Hint:** Remember the positions where nitration is likely to occur based on substituent effects.

### Step 5: Hydrolysis to Regenerate Aniline
After the nitration is complete, the final step involves hydrolyzing the N-acetylaniline back to aniline using an acidic condition (H3O+). This step regenerates the original amino group.

**Hint:** Consider the conditions required to revert the protecting group.

### Final Answer
The reagent used for the protection of the amino group during the nitration of aniline is **acetic anhydride**.

### Summary of Steps
1. Identify the reactivity of the amino group in aniline.
2. Choose a suitable protecting reagent (acetic anhydride).
3. Form the less reactive N-acetylaniline.
4. Carry out the nitration reaction.
5. Hydrolyze to regenerate aniline.