Which of the following is an examples of Friedel Crafts reaction ?

Options

A.
B.
C.
D. All of these

Answer

To determine which of the following is an example of a Friedel-Crafts reaction, we need to understand what Friedel-Crafts reactions are and how they work. Friedel-Crafts reactions are electrophilic aromatic substitution reactions that involve the introduction of an alkyl or acyl group into an aromatic ring in the presence of a Lewis acid catalyst.

### Step-by-Step Solution:

1. **Understanding Friedel-Crafts Reactions**:
Friedel-Crafts reactions can be classified into two types: alkylation and acylation. Both types require a Lewis acid catalyst, such as AlCl3, to generate a reactive carbocation or acylium ion that can react with the aromatic compound.

2. **Identifying the Lewis Acid**:
In Friedel-Crafts reactions, the Lewis acid (like AlCl3) interacts with the alkyl halide or acyl halide to form a carbocation or acylium ion. For example, when CH3Cl is used, AlCl3 polarizes the bond, leading to the formation of a methyl carbocation (CH3+).

3. **Electrophilic Attack on the Benzene Ring**:
The generated carbocation (or acylium ion) then acts as an electrophile and attacks the π electrons of the benzene ring, resulting in the substitution of a hydrogen atom on the benzene ring with the alkyl or acyl group.

4. **Examples of Friedel-Crafts Reactions**:
- **Alkylation**: An example would be the reaction of benzene with CH3Cl in the presence of AlCl3, which leads to the formation of toluene (C6H5CH3).
- **Acylation**: An example would be the reaction of benzene with acetic anhydride (CH3CO)2O in the presence of AlCl3, which leads to the formation of acetophenone (C6H5COCH3).

5. **Conclusion**:
To answer the question, we need to look for options that involve either alkylation or acylation of benzene in the presence of a Lewis acid. The correct option will be one that illustrates this process.