Butane nitrile can be prepared by heating

Options

A. propyl chloride with alc. KCN
B. butyl chloride with alc. KCN
C. propyl chloride with alc. AgCN
D. butyl chloride with alc. AgCN

Answer

To prepare butane nitrile, we can use the reaction of a suitable haloalkane with potassium cyanide (KCN). Here’s a step-by-step breakdown of the process:

### Step 1: Identify the starting materials
We need a haloalkane that has four carbon atoms (butane) and potassium cyanide (KCN) as our nucleophile. The haloalkane can be 1-bromobutane (C4H9Br) or 1-chlorobutane (C4H9Cl).

### Step 2: Write the reaction
The reaction involves the nucleophilic substitution of the halogen (Br or Cl) in the haloalkane by the cyanide ion (CN⁻) from KCN. The general reaction can be represented as:
\[ \text{R-X} + \text{KCN} \rightarrow \text{R-CN} + \text{KX} \]
Where R is the butyl group (C4H9), and X is the halogen (Br or Cl).

### Step 3: Perform the reaction
When we heat the mixture of 1-bromobutane (or 1-chlorobutane) with KCN, the cyanide ion attacks the carbon atom bonded to the halogen, resulting in the formation of butane nitrile (butyronitrile) and potassium halide (KX).

For example, using 1-bromobutane:
\[ \text{C4H9Br} + \text{KCN} \rightarrow \text{C4H9CN} + \text{KBr} \]

### Step 4: Product formation
The product formed is butane nitrile (C4H9CN), which is also known as butyronitrile. The potassium halide (KBr or KCl) is a byproduct of the reaction.

### Conclusion
Thus, by heating 1-bromobutane (or 1-chlorobutane) with potassium cyanide, we can effectively prepare butane nitrile.

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