(i) From Cumene:
Phenol is prepared commercially from cumene. Cumene is isopropyl benzene formed by the alkylation of benzene with propane in the presence of H3PO4 (Friedel Craft reaction) at 523 K).
Oxygen is bubbled through the above solution to form cumene hydroperoxide which is decomposed with aqueous acid to form phenol and acetone as follows:
(ii) From Coaltar:
Phenol can also be prepared from the middle oil fraction (440 to 503 K) of coal tar distillation which mainly consists of phenol and naphthalene. Upon cooling the fraction, crystals of naphthalene separate out. The remaining oily solution is washed with dilute H2SO4 to dissolve the basic impurities. From the solution, left phenol is extracted with aqueous NaOH to form soluble sodium phenate. CO2 is then blown through the solution to liberating phenol.
