Preparation of Phenol From Coal Tar
Phenol is commercially prepared from the middle oil fraction (443-503K) of coal tar distillate in which it occurs with cresols and naphthalene. First naphthalene is removed by chilling the fraction. The remaining oil is now treated with H2SO4 to remove basic impurities and phenol is then extracted with dilute caustic soda. The aqueous layer is separated and phenol is precipitated with H2SO4 or CO2. It is finally purified by distillation.
Preparation of Phenol From Cumene
Nowadays, phenol is manufactured from the hydrocarbon cumene. Cumene (isopropyl benzene) is first prepared from benzene and propene by Friedel-Crafts reaction in presence of phosphoric acid of aluminum oxide. Cumene is oxidized in presence of air to cumene hydroperoxide, which is then converted to phenol and acetone by treating it with dilute acid. Acetone, a byproduct of this reaction, is also obtained in large quantity by this method.
Phenol has a melting point of 314 K and it is moderately soluble in water (8% at 298K).
Uses of Phenol
Phenol is a strong antiseptic. It is widely used as a raw material for the manufacture of important dyes, drugs and pharmaceuticals, polymers like Bakelite a and a number of organic chemicals like salicylic acid, picric acid, phenolphthalein etc.
For preparation of Phenol by chemical method visit Prepration of phenol
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