Q.How is phenol prepared from

Step 1. (i) From chlorobenzene (Dow's process): chlorobenzene is hydrolysed with 6-8% NaOH at high pressure (about 300 bar) and 633 K in a closed vessel, giving sodium phenoxide; acidifying this with dilute HCl liberates phenol.

Step 2. C6H5-Cl + NaOH (633 K, 300 bar) gives C6H5-ONa + NaCl; then C6H5-ONa + HCl gives C6H5-OH + NaCl.

Step 3. (ii) From isopropylbenzene/cumene: cumene is first made by Friedel-Crafts alkylation of benzene with propene (H3PO4 catalyst, 523 K); air is then passed through cumene with 5% aqueous Na2CO3 to oxidise it to cumene hydroperoxide. …

Recall each route's named process (Dow's process; the cumene process) and write both stages -- the ring-transformation step, then t …

• Omitting the acidification step -- both routes give the sodium PHENOXIDE first, which must then be acidified with dilute HCl to release free phenol. …