![]() "Chlorinated Hydrocarbons" in Ullmann's Encyclopedia of Industrial Chemistry, 2006, Wiley-VCH, Weinheim. ^ "Compound Summary: Tetrachloroethylene".National Institute for Occupational Safety and Health (NIOSH). Immediately Dangerous to Life or Health Concentrations (IDLH). ^ a b c d e NIOSH Pocket Guide to Chemical Hazards.Products of biodegradation products include trichloroethylene, cis- 1,2-dichloroethene and vinyl chloride full degradation converts tetrachloroethylene to ethylene and chloride. In addition to bioremediation, TCE hydrolyzes on contact with soil. under aerobic conditions by cometabolism by Pseudomonas sp. Bioremediation entails reductive dechlorination by Dehalococcoides sp. Chemical treatment involves reducing metals such as iron powder. In principle, tetrachloroethylene contamination can be remediated by chemical treatment or by bioremediation. In Europe, the Scientific Committee on Occupational Exposure Limits (SCOEL) recommends for tetrachloroethylene an occupational exposure limit (8 hour time-weighted average) of 20 ppm and a short-term exposure limit (15 min) of 40 ppm. Tetrachloroethylene and trichloroacetic acid (TCA), a breakdown product of tetrachloroethylene, can be detected in the blood. Because it is stored in the body's fat and slowly released into the bloodstream, tetrachloroethylene can be detected in the breath for weeks following a heavy exposure. Tetrachloroethylene exposure can be evaluated by a breath test, analogous to breath-alcohol measurements. Tetrachloroethylene exposure has been linked to pronounced acquired color vision deficiencies after chronic exposure. National Institute for Occupational Safety and Health has compiled extensive health and safety information for tetrachloroethylene, including recommendations for dry cleaning establishments. Īt temperatures over 315 ☌ (599 ☏), such as in welding, tetrachloroethylene can be oxidized into phosgene, an extremely poisonous gas. Also, tetrachloroethylene has been shown to cause liver tumors in mice and kidney tumors in male rats. Tetrachloroethylene dissolves fats from the skin, potentially resulting in skin irritation.Īnimal studies and a study of 99 twins showed there is a "lot of circumstantial evidence" that exposure to tetrachloroethylene increases the risk of developing Parkinson's disease ninefold. Like many chlorinated hydrocarbons, tetrachloroethylene is a central nervous system depressant and can enter the body through respiratory or dermal exposure. The International Agency for Research on Cancer has classified tetrachloroethylene as a Group 2A carcinogen, which means that it is probably carcinogenic to humans. "Reports of human injury are uncommon despite its wide usage in dry cleaning and degreasing". The acute toxicity of tetrachloroethylene "is moderate to low". In the early 20th century, tetrachloroethene was used for the treatment of hookworm infestation. Tetrachloroethylene was once extensively used as an intermediate in the manufacture of HFC-134a and related refrigerants. It appears in a few consumer products including paint strippers and spot removers. It is also used to degrease metal parts in the automotive and other metalworking industries, usually as a mixture with other chlorocarbons. For these reasons, it is widely used in dry cleaning. Otherwise it is volatile, highly stable, and nonflammable. Tetrachloroethylene is an excellent solvent for organic materials. Trichloroethylene is a major byproduct, which is separated by distillation. This reaction can be catalyzed by a mixture of potassium chloride and aluminium chloride or by activated carbon. When 1,2-dichloroethane is heated to 400 ☌ with chlorine, tetrachloroethylene is produced by the chemical reaction:ĬlCH 2CH 2Cl + 3 Cl 2 → Cl 2C=CCl 2 + 4 HCl Several other methods have been developed. Side products include carbon tetrachloride, hydrogen chloride, and hexachlorobutadiene. The method is related to Faraday's discovery since hexachloroethane is generated and thermally decomposes. Most tetrachloroethylene is produced by high temperature chlorinolysis of light hydrocarbons. British physicist and chemist Michael Faraday first synthesized tetrachloroethylene in 1821 by thermal decomposition of hexachloroethane.
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