How will you convert benzene into n-propyl benzene?a)Friedel-Crafts Alkylationb)Friedel-Crafts Acylationc)Friedel-Crafts Alkylation followed by clemmensen reductiond)Friedel-Crafts Acylation followed by clemmensen reductionCorrect answer is option 'D'. Can you explain this answer?

Question

Answer

To convert benzene into n-propyl benzene, the most suitable method is Friedel-Crafts Acylation followed by Clemmensen reduction. Let's break down the process step by step:

**Friedel-Crafts Acylation:**
1. Friedel-Crafts Acylation is a reaction that involves the substitution of a hydrogen atom on an aromatic ring with an acyl group.
2. In this case, benzene will react with an acyl chloride, such as propionyl chloride (CH3CH2COCl), in the presence of a Lewis acid catalyst, typically aluminum chloride (AlCl3).
3. The reaction proceeds via the formation of a complex between the Lewis acid and the acyl chloride, which activates the acyl chloride for electrophilic attack by the benzene ring.
4. The acyl group is then transferred to the benzene ring, resulting in the formation of the intermediate product, acetophenone (C6H5C(O)CH3).

**Clemmensen Reduction:**
1. The next step in the conversion of benzene to n-propyl benzene is the Clemmensen reduction.
2. The Clemmensen reduction is a chemical reaction that involves the reduction of a carbonyl group to a methylene group using zinc amalgam (Zn/Hg) and concentrated hydrochloric acid (HCl).
3. In this case, acetophenone is reduced to the corresponding alkylbenzene, which is propylbenzene (C6H5CH2CH2CH3).
4. The reduction occurs by the formation of a zinc-mercury amalgam, followed by the transfer of hydrogen atoms from the amalgam to the carbonyl group.
5. The resulting methylene group replaces the carbonyl group, resulting in the formation of propylbenzene.

Therefore, the correct answer is option (d) Friedel-Crafts Acylation followed by Clemmensen reduction. This combination of reactions allows for the introduction of the n-propyl group onto the benzene ring, resulting in the formation of n-propyl benzene.

Answer

Friedel-Crafts Acylation followed by clemmensen reduction of ketone will give n-propyl benzene. Clemmensen reduction is a chemical reaction described as a reduction of ketones (or aldehydes) to alkanes using zinc amalgam and hydrochloric acid.

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