PHENOLS
Phenols are the hydroxy derivatives of aromatic hydrocarbons in which the hydrox
OH) is directly attached to the carbon atom of the aromatic rings.
Phenol can be obtained by replacing one or more hydrogen atoms of benzene wi
groups.
As –OH group is attached to an aryl group in phenol, they are represented by gene
Ar-OH where, Ar may be phenyl or substituted phenyl or other aryl group.
When –OH group is not directly linked with benzene ring but present in the alkyl si
ArCH2-OH, then it is aromatic alcohol but are not phenol.
, Classification and Nomenclature of Phenols
Like alcohols, phenols may also be classified as monohydric, dihydric, trihydric or
alcohols according to they contain one, two, three or more hydroxyl group respective
Monohydric
phenols
Dihydric
phenols
Trihydric
phenols
-COOH > -SO3H, COOR > -CHO > CO > -OH > -NH2 > X > -NO2 > -R
, Preparation of Phenol
1. From Chlorobenzene (Dow’s process):
When chlorobenzene is heated with NaOH at about 350°C under pressure gives sodi
phenoxide, which further acidification with dil. HCl gives phenol.
2. Hydrolysis of diazonium salt:
If Benzene diazonium salt is boiled with water in presence of acid gives phenol.
Phenols are the hydroxy derivatives of aromatic hydrocarbons in which the hydrox
OH) is directly attached to the carbon atom of the aromatic rings.
Phenol can be obtained by replacing one or more hydrogen atoms of benzene wi
groups.
As –OH group is attached to an aryl group in phenol, they are represented by gene
Ar-OH where, Ar may be phenyl or substituted phenyl or other aryl group.
When –OH group is not directly linked with benzene ring but present in the alkyl si
ArCH2-OH, then it is aromatic alcohol but are not phenol.
, Classification and Nomenclature of Phenols
Like alcohols, phenols may also be classified as monohydric, dihydric, trihydric or
alcohols according to they contain one, two, three or more hydroxyl group respective
Monohydric
phenols
Dihydric
phenols
Trihydric
phenols
-COOH > -SO3H, COOR > -CHO > CO > -OH > -NH2 > X > -NO2 > -R
, Preparation of Phenol
1. From Chlorobenzene (Dow’s process):
When chlorobenzene is heated with NaOH at about 350°C under pressure gives sodi
phenoxide, which further acidification with dil. HCl gives phenol.
2. Hydrolysis of diazonium salt:
If Benzene diazonium salt is boiled with water in presence of acid gives phenol.
