Benzene Hexachloride Introduction
Benzene hexachloride (BHC) is an organochlorine chemical compound which is an isomer of gammexane with the formula C6H6C16. As it is produced by the chlorination of benzene that’s why it is commonly known as benzene hexachloride. Although it is also known as Lindane or gamma – hexachlorocyclohexane (𝛾 - HCH). It has various other names as well such as gammaxene or Gammallin etc. Its IUPAC name is 1,2,3,4,5,6 – hexachlorocyclohexane. Its production and agricultural use are banned in almost 182 countries. Although its pharmaceutical use is allowed in almost all the countries.
Preparation of Benzene Hexachloride
English scientist Michael Faraday synthesized benzene hexachloride for the first time in 1825. Although it was 1st isolated in 1912 by Dutch Chemist Teunis van der Linden. That’s why the compound is named after him.
It is prepared by light induced chlorination of benzene. In presence of UV light and heat, benzene undergoes an additional reaction with chlorine molecules and gives lindane or benzene hexachloride. Reaction is given below –
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In this reaction benzene loses its aromaticity and changes into an alkane. Thus, in the reaction delocalization of pi – bonds in the benzene ring is removed by addition of chlorine atoms to each carbon atom of the benzene ring.
Benzene Hexachloride Structure – C6H6C16
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Benzene Hexachloride Structural Formula
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Lindane consists of six atoms of carbon, hydrogen, and chlorine. C6H6C16is the chemical formula of lindane. Chlorine and hydrogen atoms of lindane can stick above and below the ring randomly. Due to this it has a number of geometric isomers. Although it is not an aromatic compound and doesn't have a delocalized pi-electron system in the ring. Its isomers such as gamma – hexachlorocyclohexane (𝛾 - HCH), Gammexane etc. are used as insecticides.
Properties of Benzene Hexachloride
Properties of benzene hexachloride are as follows –
Its molecular formula is C6H6C16.
Its molecular weight is 291g/mol
Its density is 1.89 at 66℉.
Its boiling point is 323℃.
Its melting point is 113℃.
Uses of Benzene Hexachloride
Benzene hexachloride and isomers are used in various fields. Some of its uses are listed below –
It is used for pharmaceutical treatment of lice and scabies (or seven – year itch).
It is also used as an agricultural insecticide. Although presently its agricultural use is regulated or banned in many countries. During 1950-2000, 600000 tons of BHC was produced globally for agricultural use.
It is used in medicinal shampoo or lotions.
It is used for second line treatments of various diseases.
It is used for seed treatment.
Benzene Hexachloride Health Risks
According to the World Health Organization, BHC or lindane is moderately acutely toxic. This is the reason its usage in agriculture has been regulated or banned. Its higher amount can affect the nervous system and its production process is harmful for the environment.
Large amounts of lindane can cause headache, dizziness, convulsions or even death in rare cases. It can affect the brain development of the child and can alter the thyroid hormone levels. At the level of 50 mg/m3 and above, lindane may cause immediate death or can be very dangerous for life and health.
It is listed as one of the extremely hazardous substances in the list of extremely hazardous substances in the US. ‘International Agency for Research on Cancer’ declared lindane a human carcinogen. Although WHO declared lindane as non – carcinogenic to humans, India’s BIS considered BHC a ‘confirmed carcinogen’.
It causes some adverse reactions which may cause seizures, skin irritation, itching, rash, burning sensation. These reactions of lindane make the skin very sensitive. It cannot be used for premature babies as it may cause severe neurotoxicity.
Lindane pollutes the environment. It is termed as a persistent organic pollutant or forever chemical. As it is a long lasting chemical in the environment. Its agricultural use is the primary reason for its presence in the environment. Through agriculture, it enters the food chains as well. The production process of lindane gives a large amount of toxic waste. According to studies, every ton of BHC production gives ten tons of toxic waste. BHC in soil can leach to groundwater and can reach to the atmosphere by volatilization and therefore can be deposited by rainfall.
Due to its agricultural applications a large quantity of lindane has been reported in the human body which is very dangerous for human health.
Thus, lindane or BHC should be used vigilantly. All guidelines of the environmental protection agency and world health organization regarding lindane must be followed during its production and usage for a healthy environment and ecosystem.
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Chemical Properties of Benzene Hexachloride
Benzene hexachloride is one of the important topics in school chemistry and students must thoroughly know about its chemical properties as it holds high chances of appearing in the exams and has high weightage too which could make it easier for students to score high in their exams. Now let’s understand what are the chemical properties of benzene hexachloride. C6H6C16 is the molecular formula for benzene hexachloride, and it’s molecular weight is 290.8, whereas its parent compound is CID 241 (Benzene) and component compounds as CID 313 (Hydrochloric acid) CID 241 (Benzene)Potential
Exposure of Benzene Hexachloride
BHC's main commercial application is for its insecticidal capabilities. Agricultural chemicals, pesticides, pharmaceuticals, and veterinary drugs all include -BCC. Although the 7-isomer has the maximum acute toxicity, the other isomers have some action as well. Purifying the 7-isomer from the less active isomers is often favorable. The -isomer affects the neurological system of insects, mostly at the nerve ganglia level. As a result, lindane has been used to combat insects in a variety of settings, including the treatment of animals, buildings, humans for ectoparasites, clothing; water for mosquitoes; living plants; seeds, and soils.
Some applications, such as storing food, have been abandoned due to high residues. On September 1, 1976, the primary domestic producer of technical grade BHC requested revocation of its BHC registrations through voluntary action. All of the pesticide products containing the registrants of BHC voluntarily terminated their registrations or switched their previous BHC products to lindane formulations as of July 21, 1978.
Incompatibilities of Benzene Hexachloride
Contact with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, and others) can result in fires or explosions. Alkaline materials, strong bases, strong acids, oxoacids, and epoxides should be avoided. When it comes into contact with powdered iron, aluminum, zinc, or strong bases, it decomposes into trichlorobenzene.
Waste Disposal
The destructive pyrolysis of benzene hexachloride at temperatures of 400 to 500°C has been developed using a catalyst mixture containing 5 to 10% zinc chloride, cupric chloride, or aluminum chloride on activated carbon and ferric chloride.
FAQs on Benzene Hexachloride
1. What is BHC?
BHC is the abbreviation of benzene hexachloride. Benzene hexachloride (BHC) is an organochlorine chemical compound which is an isomer of gammexane with the formula C6H6C16.
2. What is Benzene Hexachloride Used for?
Benzene hexachloride is mainly used in agricultural and pharmaceutical fields. It is used for treatment of lice and scabies.
3. Why is Benzene Hexachloride Dangerous?
Benzene hexachloride is dangerous as it is a persistent organic pollutant and may cause various harmful effects to our environment and ecosystem. Other than that, over-exposure to benzene hexachloride may cause cancer in humans. India’s BIS considers BHC a ‘confirmed carcinogen’.
4. What is the Common Name of Benzene Hexachloride?
Benzene hexachloride is also known by its other name which is Lindane, also known as gamma-hexachlorocyclohexane (γ-HCH), gammaxene, Gammallin and sometimes incorrectly called benzene hexachloride (BHC), is an organochlorine chemical and isomer of hexachlorocyclohexane that has been used as lice and scabies treatment as well as an agricultural insecticide. Lindane is also a neurotoxin which interferes with the GABA neurotransmitter function by binding it to the picrotoxin binding site on the GABAA receptor-chloride channel complex.
Lindane is a type of carcinogen that directly affects the nervous system, liver, and kidneys in humans. It's unclear till now whether lindane is an endocrine disruptor or not. There are other health risks with a variety of side effects that have been reported with lindane pharmaceuticals, ranging from skin irritation problems to seizures and also in some rare cases leads to death. Burning sensations, continuous itching, dryness, and rashes are the most common side effects that have come to knowledge till now. While very serious side effects are uncommon and almost always have been reported as the result of misuse, adverse reactions have occurred when the product was used properly. The FDA now requires a so-called black box warning on lindane products, which explains the risks and proper use of lindane products as a result of this.
5. Who Discovered Benzene Hexachloride and in Which Year Was it Discovered?
Benzene hexachloride came into existence first when an English scientist named Michael Faraday synthesized benzene hexachloride for the first time in the year 1825. It was at first although isolated in the year 1912 by a Dutch Chemist named as Teunis van der Linden on who’s name later the compound was named as Linden. The insecticidal characteristics of benzene hexachloride were discovered in the year 1944 with the γ-isomer (read as gamma-isomer), which is 1,000 times more poisonous and dangerous than any of the other diastereomers generated in the reaction period. The main orientations of the chlorine atoms with regard to the carbon ring are the structural distinctions between these individuals.
Ban from the government on the manufacturing and use of benzene hexachloride (BHC) after this came into effect in India from April 1, vector control and the pest control operations and programs in the field of agriculture have been forced to look for safer alternatives now. Environmentalists and health activists have also welcomed the government ban over it.
