Dictionary:
tet·ra·chlo·ro·eth·yl·ene (tĕt'rə-klôr'ō-ĕth'ə-lēn', -klōr'-) also tet·ra·chlor·eth·yl·ene
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| 5min Related Video: tetrachloroethylene |
| Encyclopedia of Public Health: Tetrachloroethylene |
Tetrachloroethylene is a dry-cleaning agent and industrial degreaser that often goes under the name perchloroethylene (PERC). The National Institute of Occupational Safety and Health estimates that 650,000 U.S. workers are exposed to PERC annually. PERC enters the environment through evaporation or through transport into groundwater and drinking water supplies. Through widespread use it has become a frequent drinking water contaminant, and it is present in approximately half of the nation's Superfund sites.
PERC has a low odor threshold and its smell is that associated with a dry-cleaning establishment. High levels of PERC released in workplace accidents can produce loss of consciousness and death. There is some evidence that longer-term exposures to lower levels at the workplace can lead to kidney and liver damage, cancer, neurological impairment, including changes in memory and learning, and to problems with visual perception. Reproductive and developmental effects have been suggested.
Whether any of these effects occur at the much lower levels present in the general environment is controversial. There is increased pressure to regulate PERC because of particular concern for children living in apartment buildings above dry-cleaning establishments, and because as a chlorinated compound it can be a precursor of dioxins.
(SEE ALSO: Dioxins; Toxicology)
Bibliography
New York State Department of Health (1997). Tetrachloroethylene (PERC) in Indoor and Outdoor Air: Fact Sheet. Albany, NY: Author.
U.S. Health Department of Health and Human Services (1997). Toxicological Profile for Tetrachloroethylene. Washington, DC: Public Health Service, Agency for Toxic Substances and Disease Registry.
— BERNARD D. GOLDSTEIN
| Veterinary Dictionary: tetrachloroethylene |
A clear, colorless liquid used extensively at one time as an anthelmintic but now superseded in all species by safer and more effective drugs. Overdosing causes incoordination immediately, hepatic insufficiency later.
| WordNet: tetrachloroethylene |
The noun has one meaning:
Meaning #1:
anthelmintic agent used against hookworm and other nematodes
Synonyms: tetrachlorethylene, ethylene tetrachloride, carbon dichloride
| Wikipedia: Tetrachloroethylene |
| Tetrachloroethylene | |
|---|---|
| IUPAC name |
tetrachloroethene
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| Other names | perchloroethene, perchloroethylene, perc, PCE |
| Identifiers | |
| CAS number | 127-18-4 |
| EC number | 204-825-9 |
| RTECS number | KX3850000 |
| SMILES |
C(=C(Cl)Cl)(Cl)Cl
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| Properties | |
| Molecular formula | C2Cl4 |
| Molar mass | 165.8 g/mol |
| Appearance | Clear, colorless liquid |
| Density | 1.622 g/cm3, liquid |
| Melting point |
−19 °C (254 K) |
| Boiling point |
121.1 °C (394 K) |
| Solubility in water | 0.015 g/100 ml (20 °C) |
| Viscosity | 0.89 cP at 25 °C |
| Hazards | |
| MSDS | External MSDS |
| R-phrases | 40-51/53 |
| S-phrases | 23-36/37-61 |
| Flash point | Not flammable |
| Related compounds | |
| Related Related Haloforms | tetrabromoethylene tetraiodoethylene |
| Related compounds | trichloroethylene dichloroethene tetrachloroethane |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Tetrachloroethylene, also known under its systematic name tetrachloroethene and many other names, is a chlorocarbon with the formula Cl2C=CCl2. It is a colourless liquid widely used for dry cleaning of fabrics, hence it is sometimes called "dry-cleaning fluid." It has a sweet odor detectable by most people at a concentration of 1 part per million (1 ppm). Worldwide production was about 1 megaton in 1985.[1]
Contents |
Michael Faraday first synthesized tetrachloroethene in 1821 by thermal decomposition of hexachloroethane.
Most tetrachloroethene is produced by high temperature chlorinolysis of light hydrocarbons. The method is related to Faraday's discovery since hexachloroethane is generated and thermally decomposes.[1] Side products include carbon tetrachloride, hydrogen chloride, and hexachlorobutadiene.
Several other methods have been developed. When 1,2-dichloroethane is heated to 400 °C with chlorine, tetrachloroethene is produced by the chemical reaction:
This reaction can be catalyzed by a mixture of potassium chloride and aluminium chloride or by activated carbon. Trichloroethylene is a major byproduct, which is separated by distillation.
Tetrachloroethylene is an excellent solvent for organic materials. Otherwise it is volatile, highly stable, and nonflammable. For these reasons, it is widely used in dry cleaning. Usually as a mixture with other chlorocarbons, it is also used to degrease metal parts in the automotive and other metalworking industries. It appears in a few consumer products including paint strippers and spot removers.
Tetrachloroethene was once extensively used as an intermediate in the manufacture of HFC-134a and related refrigerants. In the early 20th century, tetrachloroethene was used for the treatment for hookworm infestation.[2]
The International Agency for Research on Cancer has classified tetrachloroethene as a Group 2A carcinogen, which means that it is probably carcinogenic to humans.[3] Like many chlorinated hydrocarbons, tetrachloroethene is a central nervous system depressant and can enter the body through respiratory or dermal exposure.[4] Tetrachloroethene dissolve fats from the skin, potentially resulting in skin irritation.
Tetrachloroethene is a common soil contaminant. Because of the mobility of PCE in groundwater, its toxicity at low levels, and its density (which causes it to sink below the water table), cleanup activities are more difficult than for oil spills. Recent research has focused on the in place remediation of soil and ground water pollution by tetrachloroethylene. Instead of excavation or extraction for above-ground treatment or disposal, tetrachloroethylene contamination has been successfully remediated by chemical treatment or bioremediation. Bioremediation has been successful under anaerobic conditions by reductive dechlorination by Dehalococcoides sp. and under aerobic conditions by cometabolism by Pseudomonas sp. [5][6]
Tetrachloroethene exposure can be evaluated by a breath test, analogous to breath-alcohol measurements. Because it is stored in the body's fat and slowly released into the bloodstream, tetrachloroethene can be detected in the breath for weeks following a heavy exposure. Tetrachloroethylene and trichloroacetic acid (TCA), a breakdown product of tetrachloroethene, can be detected in the blood.
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
| perchloroethylene (organic chemistry) | |
| Perks | |
| volatile organic compounds (engineering) |
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