Cumene on oxidation in air gives a compound, X. This on reaction with dilute acid gives Y and Z. Y reacts with sodium metal and not Z. What is Z?
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The cumene process is a very important industrial reaction to remember. The overall transformation is:
Cumene + Air \(\rightarrow\) Cumene hydroperoxide \(\xrightarrow{H^+}\) Phenol + Acetone.
It's an efficient way to produce two valuable chemicals from cheap starting materials (benzene and propene).
This sequence describes the cumene process, a major industrial method for synthesizing phenol and acetone.
Step 1: Identify compound X.
Cumene (isopropylbenzene) is oxidized in the presence of air. The oxidation occurs at the tertiary carbon, forming cumene hydroperoxide.
The structure of cumene is C\(_6\)H\(_5\)-CH(CH\(_3\))\( _2 \).
The reaction is: \( \text{C}_6\text{H}_5\text{-CH(CH}_3\text{)}_2 + \text{O}_2 \rightarrow \text{C}_6\text{H}_5\text{-C(OOH)(CH}_3\text{)}_2 \).
So, X is cumene hydroperoxide.
Step 2: Identify compounds Y and Z.
Compound X (cumene hydroperoxide) is treated with a dilute acid (like H\(_2\)SO\(_4\)). It undergoes a rearrangement and cleavage to form phenol and acetone.
\( \text{C}_6\text{H}_5\text{-C(OOH)(CH}_3\text{)}_2 \xrightarrow{\text{H}^+} \text{C}_6\text{H}_5\text{-OH} + \text{CH}_3\text{-C(=O)-CH}_3 \).
The products are phenol (Y or Z) and acetone (Z or Y).
Step 3: Distinguish between Y and Z.
We are told that Y reacts with sodium metal, but Z does not.
Phenol (C\(_6\)H\(_5\)-OH) has an acidic hydroxyl group. It reacts with active metals like sodium to liberate hydrogen gas.
\( 2\text{C}_6\text{H}_5\text{-OH} + 2\text{Na} \rightarrow 2\text{C}_6\text{H}_5\text{-ONa} + \text{H}_2 \).
So, Y must be phenol.
Acetone (propanone, CH\(_3\)-C(=O)-CH\(_3\)) is a ketone. It does not have an acidic hydrogen and does not react with sodium metal under these conditions.
So, Z must be acetone.
The structure of Z is \( \text{CH}_3-\text{C(=O)-CH}_3 \), which is propanone. This matches option (C).
