Which of the following reaction is involved in the preparation of primary amines :
(i) Hofmann's bromamide reaction and
(ii) Gobriel phthalimide synthesis

Options

A. (i)
B. (ii)
C. Both of these
D. None of these

Answer

To determine which reactions are involved in the preparation of primary amines, we will analyze both the Hofmann bromamide reaction and the Gabriel phthalimide synthesis.

### Step-by-step Solution:

1. **Understanding Primary Amines**:
- Primary amines have the general formula RNH2, where R is an alkyl or aryl group. Our goal is to identify reactions that yield primary amines.

2. **Hofmann Bromamide Reaction**:
- In this reaction, a primary amide (RCONH2) is treated with bromine (Br2) in the presence of a strong base like potassium hydroxide (KOH).
- The reaction proceeds as follows:
- The primary amide reacts with Br2 and KOH at a temperature of about 343 K.
- The products of this reaction are a primary amine (RNH2), potassium bromide (KBr), water (H2O), and potassium carbonate (K2CO3).
- Example: If we take acetamide (CH3CONH2) and react it with Br2 and KOH, we get ethylamine (CH3NH2) along with by-products.
- This confirms that the Hofmann bromamide reaction produces primary amines.

3. **Gabriel Phthalimide Synthesis**:
- In this reaction, phthalimide (C6H4(CO)2NH) is treated with a strong base like KOH to form potassium phthalimide.
- The potassium phthalimide then reacts with an alkyl halide (R-X) to form N-alkyl phthalimide.
- Upon hydrolysis (typically using 20% NaOH), N-alkyl phthalimide yields a primary amine (RNH2) and sodium phthalate.
- This reaction also confirms that Gabriel phthalimide synthesis produces primary amines.

4. **Conclusion**:
- Both the Hofmann bromamide reaction and the Gabriel phthalimide synthesis yield primary amines.
- Therefore, the correct answer is that both reactions are involved in the preparation of primary amines.

### Final Answer:
Both of these reactions (i.e., Hofmann's bromamide reaction and Gabriel phthalimide synthesis) are involved in the preparation of primary amines.

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