Phenanthrene

Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) consisting of three fused benzene rings. The name 'phenanthrene' is derived from the two terms 'phenyl' and 'anthracene'. It is a white crystalline substance, which is insoluble in water but soluble in organic solvents. Phenanthrene is used in the production of drugs, explosives, and pesticides.

Structure and Properties

Phenanthrene is a planar molecule, with the molecular formula C14H10. The carbon atoms in phenanthrene are arranged in a three-ring system, with the central ring sharing two sides with the other two rings. This structure is reflected in its IUPAC name: 1,2:3,4-dibenzonaphthalene.

Phenanthrene has a molar mass of 178.23 g/mol and a density of 1.179 g/cm3. It has a melting point of 100.2 °C and a boiling point of 340 °C. It is less reactive than its isomer anthracene.

Synthesis

Phenanthrene can be synthesized by various methods, including the Haworth reaction, the Barton-Zard synthesis, and the Friedel-Crafts reaction. It can also be obtained from coal tar, a by-product of the production of coke and coal gas from coal.

Uses

Phenanthrene is used in the synthesis of various drugs, including phenanthridine derivatives, which have anti-cancer properties. It is also used in the production of explosives and pesticides. In addition, it is used as a starting material in the synthesis of other polycyclic aromatic hydrocarbons.

Health Effects

Exposure to phenanthrene can cause skin and eye irritation. Ingestion can lead to nausea, vomiting, and abdominal pain. Long-term exposure can lead to respiratory problems and may have carcinogenic effects.

Environmental Impact

Phenanthrene is a common pollutant in the environment, mainly due to the incomplete combustion of fossil fuels. It is toxic to aquatic life and can bioaccumulate in the food chain.