Isopropyl benzene can be obtained by :

Options

A.
B.
C.
D.

Answer

To determine how isopropyl benzene can be obtained, we need to analyze the given options and the reactions involved. Isopropyl benzene, also known as cumene, can be synthesized through electrophilic substitution reactions involving benzene and appropriate alkyl halides. Here’s a step-by-step breakdown of the process:

### Step 1: Identify the reactants
We start with benzene (C6H6) as the primary reactant. Benzene is known for its high electron density due to the delocalized π electrons, making it a good substrate for electrophilic substitution reactions.

### Step 2: Understand the electrophilic substitution mechanism
In the presence of a Lewis acid catalyst like aluminum trichloride (AlCl3), an alkyl halide can react to form a carbocation, which acts as the electrophile. The general mechanism involves:
1. Formation of the electrophile from the alkyl halide.
2. Electrophilic attack on the benzene ring.
3. Restoration of aromaticity.

### Step 3: Analyze the options
1. **Option A**: Benzene + Propene in the presence of AlCl3
- Propene can form a secondary carbocation (isopropyl cation) when reacted with AlCl3, which can then react with benzene to form isopropyl benzene.

2. **Option B**: Benzene + Propyl chloride (C3H7Cl) in the presence of AlCl3
- Propyl chloride can also form a primary carbocation, but through a hydride shift, it can rearrange to a more stable secondary carbocation (isopropyl cation) that can react with benzene to form isopropyl benzene.

3. **Option C**: Benzene + Isopropyl chloride (C3H7Cl) in the presence of AlCl3
- Isopropyl chloride directly provides the isopropyl cation, which can react with benzene to yield isopropyl benzene.

4. **Option D**: Benzene + Ethyl phenyl ether
- Ethyl phenyl ether does not generate a suitable electrophile for this reaction, as it does not lead to the formation of an isopropyl cation.

### Step 4: Conclusion
Based on the analysis:
- **Options A, B, and C** can yield isopropyl benzene.
- **Option D** cannot yield isopropyl benzene.

### Final Answer:
Isopropyl benzene can be obtained by options **A, B, and C**.

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