Preparation of Phenol
Phenol can be prepared from various compounds such as haloarenes, benzene sulfonic acid, cumene, diazonium salts, Grignard reagents, etc. It can be prepared by laboratory and commercial methods. Let’s discuss these two methods below:
Laboratory Preparation of Phenol
In the laboratory, Phenol is prepared from benzene derivatives using the following method.
From benzene sulphonic acid: When benzene is treated with the mixture of( H2SO4 and SO3) it forms benzene sulphonic acid. It reacts with NaOH and forms sodium benzene sulphonate, which is converted into phenoxide by heating with molten sodium hydroxide. This acidification gives Phenol.
C6H6 (Benzene) + H2S2O7 (oleum) →C6H5SO3H (Benzene sulphonic acid) + NaOH → C6H5SO3–Na+
C6H5SO3–Na+ + NaOH –(573/623) → C6H5NaO (Sodiumphenoxide) + HCl →C6H5OH
Grignard Reagent: When oxygen gas is passed from the ether solution of the Grignard reagent, it forms an oxy compound, which, on further hydrolysis with dilute HCl, gives Phenol.
C6H5MgBr + O2 →C6H5OMgBr
C6H5OMgBr + water →C6H5OH
From diazonium salts: An aqueous solution of benzene diazonium salt on warming gives Phenol.
R−N2+X− + Water →C6H5OH
Commercial Preparation of Phenol
From Haloarenes(Dow process): Phenol can be prepared by heating chlorobenzene with 10% aqueous NaOH at about 623K under 300atm pressure in the presence of copper salt, which acts as a catalyst to form sodium phenoxide. The salt, when treated with dilute HCl, gives Phenol. This method is called the Dow process.
C6H5Cl + NaOH →C6H5O–Na+ + HCl –› Phenol
From cumene(Hock process): Cumene is oxidized in the presence of air to cumene hydroperoxide, which further hydrolysis with dilute H2SO4 gives Phenol.
Cumene + oxygen →cumenehydroperoxide + water →Phenol
Phenol (C6H5OH)
Phenol is an aromatic organic compound. Its molecular formula is C6H6O. Phenol is characterized by a hydroxyl group attached to a carbon atom that is part of an aromatic ring. It is also known as carbolic acid and consists of hydroxyl and phenyl groups attached to each other. In this article, we look into what phenol is, its structure, its classification, general properties, preparation and reactions, etc.
Table of Content
- What is Phenol?
- Classification of phenol
- Properties of phenol
- Preparation of Phenol
- Reaction of Phenol
- Derivatives of Phenol
- Uses of Phenol