Carvacrol - Arasi Lawrence Company

Carvacrol

Phenols

Phenols are aromatic compounds containing hydroxyl groups directly attached to the nucleus, and they are classified as monohydric, dihydric, trihydric phenols, etc., according as they contain one, two, three, etc., hydroxyl groups.

Monohydric phenols

Properties of Phenol

There are characteristic of monohydric phenols. Phenol is a colo(u)rless crystalline solid melting point (m.b.) 43°C, boiling point (b.p.) 182°C, which turns pink on exposure to air and light. It is moderately soluble in cold water, but is readily soluble in ethanol and ether. Phenol undergoes the Liebermann reaction ; when phenol is dissolved in concentrated sulphuric acid and a few drops of aqueous sodium nitrite added, a red colo(u)r is obtained on dilution, and turns blue when made alkaline with aqueous sodium hydroxide.

Phenol is used as an antiseptic and disinfectant, and in the preparation of dyes, drugs, bakelite, etc.

The infra-red absorption region of the phenolic hydroxyl group (O-H stretch) is the same as that for alcohols, but the nucleus may be identified by its own absorption spectrum. At the same time, there will also be present the pattern due to a substituted benzene. Furthermore, there may be complications due to intermolecular hydrogen bonding, or intramolecular hydrogen bonding in various o-derivatives.

Carvacrol (2-hydroxy-4-isopropyltoluene), boiling point (b.p.) 237°C under 760mm. pressure, is one of the chief constituents of Marjoram leaf essential (volatile) oil, from which it is obtained.