Phenols

Phenol, also known as carbolic acid or phenic acid, is an aromatic organic compound with the molecular formula C6H5OH, being the first representative of the phenol class. It is a solid, crystalline, white and volatile compound. The molecule consists of a phenyl group (-C6H5) linked to a hydroxyl group (-OH). It is slightly acidic, and must be handled with great care as it can cause burns.

Phenol group

Phenols, derivatives of phenol, are compounds in which the -OH functional group is linked to a carbon atom belonging to an aromatic nucleus. The names of phenols are formed by adding the prefix hydroxy- to the name of the aromatic hydrocarbon or by adding the suffix -ol to the root of the name of the hydrocarbon and they are part of the phenol group.

Properties

Phenol is actually a benzene to which a hydroxyl group has been substituted, so it has a slightly acidic character. It has a melting point of about 41 °C and a boiling point of 182 °C. At room temperature it appears as colorless crystals which, through oxidation or impurities, may have a pink to red-brown color. Phenol has a characteristic pungent aromatic smell. In contrast to aromatic alcohols, phenols do not have nucleophilic substitution character, being slightly electrophilic in the "para" position, phenol is about 1000 times more active than benzene.

Use

Sir Joseph Lister used phenol for the first time in 1865 as an antiseptic to disinfect wounds, but due to its irritating nature it was replaced in surgery by other antiseptics. Phenol has a caustic effect on the nerve cell membrane. Because of its bactericidal effect, it was used as a disinfectant, being also used in the cultivation of drug-producing plants as a herbicide. Phenol is also used in the production of artificial resins such as Bakelite which is a polycondensate of phenol and formaldehyde. During World War II, prisoners were killed in German camps by intracardiac injections of phenol. For wooden constructions, phenol-resorcinol-formaldehyde glue is used.

Obtaining

Several methods of obtaining phenol are known, of which two methods are more widespread:

Cumene oxidation method (Synthesis of phenol according to the Hock method):
Chimie
Benzenesulfonic acid method with sodium hydroxide (alkaline melting of salts of aromatic sulfonic acids):
Chimie