Which step is used to produce 1-Chloro-3-ethylbenzene

Options

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B.
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D.

Answer

To produce 1-Chloro-3-ethylbenzene, we can follow these steps:

### Step 1: Starting Material
Begin with benzene as the starting material. Benzene is a six-carbon aromatic compound with alternating double bonds.

### Step 2: Friedel-Crafts Acylation
React benzene with acetic anhydride (or acetyl chloride, CH3COCl) in the presence of a Lewis acid catalyst, such as aluminum chloride (AlCl3). This reaction will introduce an acetyl group (COCH3) onto the benzene ring, forming acetophenone.

**Reaction:**
\[ \text{C}_6\text{H}_6 + \text{CH}_3\text{COCl} \xrightarrow{\text{AlCl}_3} \text{C}_6\text{H}_5\text{COCH}_3 \]

### Step 3: Directing Effects
The acetyl group (keto group) is a meta-directing group due to its electron-withdrawing nature. Therefore, any further electrophilic substitution will occur at the meta position relative to the acetyl group.

### Step 4: Electrophilic Substitution
Next, perform an electrophilic substitution reaction with chlorine (Cl2) in the presence of a catalyst (like FeCl3). The chlorine will substitute at the meta position of the acetophenone, resulting in the formation of 1-Chloro-3-ethylbenzene.

**Reaction:**
\[ \text{C}_6\text{H}_5\text{COCH}_3 + \text{Cl}_2 \xrightarrow{\text{FeCl}_3} \text{C}_6\text{H}_4\text{Cl}\text{COCH}_3 \]

### Step 5: Reduction (if necessary)
If the ethyl group is required, you can reduce the ketone (acetophenone) to an ethyl group using zinc and hydrochloric acid (Zn/HCl). This will yield the final product, 1-Chloro-3-ethylbenzene.

**Final Reaction:**
\[ \text{C}_6\text{H}_4\text{Cl}\text{COCH}_3 \xrightarrow{\text{Zn/HCl}} \text{C}_6\text{H}_4\text{Cl}\text{C}_2\text{H}_5 \]

### Conclusion
Thus, the correct step to produce 1-Chloro-3-ethylbenzene involves starting with benzene, performing Friedel-Crafts acylation to introduce the acetyl group, and then conducting electrophilic substitution with chlorine.

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