Pentachlorobenzene

Pentachlorobenzene (PeCB) is a chlorocarbon that is classified as a persistent organic pollutant (POP). It is a white crystalline solid that is nearly insoluble in water but soluble in organic solvents. It is used primarily as a chemical intermediate in the manufacture of other chemicals.

Chemical Properties

Pentachlorobenzene has the chemical formula C6Cl5H. It is a derivative of benzene, where five of the hydrogen atoms have been replaced by chlorine atoms. It has a molecular weight of 250.33 g/mol. It is non-flammable and has a melting point of 166-168 °C and a boiling point of 323 °C.

Uses

Pentachlorobenzene was used in the past as a fungicide and as a flame retardant in plastics. However, due to its toxicity and persistence in the environment, its use has been largely phased out. Today, it is primarily used as a chemical intermediate in the manufacture of other chemicals, including hexachlorobenzene and pentachlorophenol.

Health Effects

Exposure to pentachlorobenzene can cause a variety of health effects. Short-term exposure can cause irritation of the skin, eyes, and respiratory tract. Long-term exposure can lead to liver and kidney damage, and may also increase the risk of cancer. It is considered a possible human carcinogen by the International Agency for Research on Cancer (IARC).

Environmental Impact

Pentachlorobenzene is a persistent organic pollutant, meaning it does not readily break down in the environment. It can accumulate in the soil and in the fatty tissues of animals. It is also capable of long-range transport, and has been detected in remote regions such as the Arctic.

Regulation

Due to its toxicity and persistence in the environment, the production and use of pentachlorobenzene is regulated in many countries. It is listed as a POP under the Stockholm Convention, an international treaty designed to eliminate or restrict the production and use of persistent organic pollutants.