The reagent that brings about the conversion of butanol to chlorobutane is

Options

A. `SOCl_(2)`
B. `PCl_(5)`
C. `PCl_(3)`
D. all of them

Answer

To convert butanol (an alcohol) to chlorobutane (an alkyl halide), we can use several reagents. Here’s a step-by-step breakdown of the process:

### Step 1: Identify the Reactants
- The reactant we have is butanol, which has the structure CH3CH2CH2CH2OH (1-butanol).
- The product we want to form is chlorobutane, which has the structure CH3CH2CH2CH2Cl (1-chlorobutane).

### Step 2: Select the Reagents
We can use the following reagents to convert butanol to chlorobutane:
1. **Thionyl Chloride (SOCl2)**
2. **Phosphorus Pentachloride (PCl5)**
3. **Phosphorus Trichloride (PCl3)**

### Step 3: Reaction with Thionyl Chloride
- When butanol reacts with thionyl chloride in the presence of a base like pyridine, the reaction proceeds as follows:
- **Reaction**:
\[ \text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{OH} + \text{SOCl}_2 \xrightarrow{\text{Pyridine}} \text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{Cl} + \text{SO}_2 + \text{HCl} \]
- This shows that thionyl chloride can effectively convert butanol to chlorobutane.

### Step 4: Reaction with Phosphorus Pentachloride
- When butanol reacts with phosphorus pentachloride, the reaction is:
- **Reaction**:
\[ \text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{OH} + \text{PCl}_5 \rightarrow \text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{Cl} + \text{POCl}_3 + \text{HCl} \]
- This indicates that PCl5 can also convert butanol to chlorobutane.

### Step 5: Reaction with Phosphorus Trichloride
- When butanol reacts with phosphorus trichloride, the reaction proceeds as follows:
- **Reaction**:
\[ \text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{OH} + \text{PCl}_3 \rightarrow \text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{Cl} + \text{H}_3\text{PO}_3 \]
- This shows that PCl3 can also convert butanol to chlorobutane.

### Conclusion
All three reagents (thionyl chloride, phosphorus pentachloride, and phosphorus trichloride) can be used to convert butanol to chlorobutane. Therefore, the answer is that **all of them** can be used for this conversion.

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