Preparation of phenols?

phenols can be prepared by the following methods.

1) hydrolysis of cholorobenzene:

in this process, chlorobenzene which can be obtained by the cholorinationof benzene, is heated at 350*C under high pressure with aqueous sodium hydroxide to get sodium phenoxide, which on acidification yields phenol.

2) pyrolosis of sodium benzenesulphonate:

this, the first commercial process for industrial synthesizing phenol , was developed in Germany in 1890. sodium benzenesulphonate is melted with sodium hydrooxide at 350*C to produce sodium phenoxide, which on acidification yields phenol.

3) oxidaton of cumene:

benzene is alkylated with propene to produce cumene, which is oxidized with air to produce cumene hydroperoxide, which on treatment with 10% sulfuric acid undergoes a hydrolytic rearrangement to yield phenol and acetone.