How will you prepare phenol from cumene?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Oxidation followed by treatment with dilute acid.
Most of the world’s phenol is made from cumene (isopropylbenzene). The process has two steps:
Oxidation: cumene is oxidised by air to cumene hydroperoxide.
\( \displaystyle \ce{C6H5-CH(CH3)2 + O2} \xrightarrow{\text{air}} \ce{C6H5-C(CH3)2-O-O-H} \)
Treatment with dilute acid: the hydroperoxide rearranges and splits into phenol and acetone.
\( \displaystyle \ce{C6H5-C(CH3)2-O-O-H} \xrightarrow{\ce{H+}/\ce{H2O}} \ce{C6H5OH + CH3COCH3} \)
So phenol is prepared from cumene by oxidation followed by treatment with dilute acid.
Why the other options are incorrect
Option (2) Reduction followed by treatment with dilute acid — Incorrect. Reduction cannot introduce the oxygen atom that phenol needs.
Option (3) Oxidation followed by treatment with dilute base — Incorrect. The oxidation step is right, but a base does not bring about the rearrangement and splitting of cumene hydroperoxide into phenol and acetone; that step needs dilute acid.
Option (4) Reduction followed by treatment with dilute base — Incorrect. Reduction adds no oxygen to cumene, so no hydroperoxide forms, and a base would not split it in any case.
NCERT (2026-27 edition):
From Cumene
