Question

Acetonitrile to Acetone

Hint:

Nitrile + Grignard reagent → Ketone (after hydrolysis).

Answer 1

Step 1: Understanding the Reactants.
Acetonitrile (\( \text{CH}_3\text{CN} \)) is a nitrile compound with a -CN group (cyano group), while acetone (\( \text{CH}_3\text{COCH}_3 \)) is a ketone with a carbonyl group (\( \text{C=O} \)) and two methyl groups attached to the carbonyl carbon.

Step 2: Reaction Type.
To convert acetonitrile to acetone, we need to reduce the nitrile group (-CN) to a carbonyl group (C=O). This can be done by hydrolyzing acetonitrile to acetamide, and then reducing the amide to acetone.

Step 3: Hydrolysis of Acetonitrile to Acetamide.
The first step is the hydrolysis of acetonitrile to acetamide, which is carried out using a strong acid (e.g., \( \text{HCl} \)) or base (e.g., \( \text{NaOH} \)) under heat. This reaction adds water to the nitrile group, forming an amide group: \[ \text{CH}_3\text{CN} + H_2O \xrightarrow{\text{acid or base}} \text{CH}_3\text{CONH}_2 \] The product is acetamide (\( \text{CH}_3\text{CONH}_2 \)).

Step 4: Reduction of Acetamide to Acetone.
Next, acetamide is reduced to acetone. This can be achieved using a reducing agent such as lithium aluminum hydride (\( \text{LiAlH}_4 \)) or by using hydrogenation. The reduction removes the amide group (-NH₂) and forms the carbonyl group (C=O), yielding acetone: \[ \text{CH}_3\text{CONH}_2 \xrightarrow{\text{LiAlH}_4} \text{CH}_3\text{COCH}_3 \] The product is acetone (\( \text{CH}_3\text{COCH}_3 \)).

Step 5: Conclusion.
To convert acetonitrile to acetone, the reaction involves first hydrolyzing acetonitrile to acetamide, followed by the reduction of acetamide to acetone. This process involves the addition of water and the use of a reducing agent.