Tetrachloroethylene
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Names | |||
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Preferred IUPAC name
Tetrachloroethene | |||
Other names | |||
Identifiers | |||
3D model (
JSmol ) |
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Abbreviations | PCE; Perc; Per | ||
1304635 | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard
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100.004.388 | ||
EC Number |
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101142 | |||
KEGG | |||
PubChem CID
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RTECS number
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UNII | |||
UN number | 1897 | ||
CompTox Dashboard (EPA)
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Properties | |||
C2Cl4 | |||
Molar mass | 165.82 g/mol | ||
Appearance | Clear, very refractive, colorless liquid | ||
Odor | Mild, sharp and sweetish[3] | ||
Density | 1.622 g/cm3 | ||
Melting point | −22.0 to −22.7 °C (−7.6 to −8.9 °F; 251.2 to 250.5 K) | ||
Boiling point | 121.1 °C (250.0 °F; 394.2 K) | ||
0.15 g/L (25 °C) | |||
Vapor pressure | 14 mmHg (20 °C)[3] | ||
−81.6·10−6 cm3/mol | |||
Refractive index (nD)
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1.505 | ||
Viscosity | 0.89 cP at 25 °C | ||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards
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Mild skin and respiratory irritant | ||
GHS labelling: | |||
Warning | |||
H351, H411 | |||
P201, P202, P273, P281, P308+P313, P391, P405, P501 | |||
NFPA 704 (fire diamond) | |||
Flash point | Not flammable | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose)
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3420 mg/kg (oral, rat)[4] 2629 mg/kg (oral, rat), >10000 mg/kg (dermal, rat)[5] | ||
LC50 (median concentration)
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4000 ppm (rat, 4 hr) 5200 ppm (mouse, 4 hr) 4964 ppm (rat, 8 hr)[6] | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible)
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TWA 100 ppm C 200 ppm (for 5 minutes in any 3-hour period), with a maximum peak of 300 ppm[3] | ||
REL (Recommended)
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Ca Minimize workplace exposure concentrations.[3] | ||
IDLH (Immediate danger) |
Ca [150 ppm][3] | ||
Safety data sheet (SDS) | External MSDS | ||
Related compounds | |||
Related analogous
organohalides |
Tetrafluoroethylene Tetrabromoethylene Tetraiodoethylene | ||
Related compounds
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Supplementary data page | |||
Tetrachloroethylene (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tetrachloroethylene, also known under the systematic name tetrachloroethene, or perchloroethylene,
History and production
French chemist Henri Victor Regnault first synthesized tetrachloroethylene in 1839 by thermal decomposition of hexachloroethane following Michael Faraday's 1820 synthesis of protochloride of carbon (carbon tetrachloride).
- C2Cl6 → C2Cl4 + Cl2
Faraday was previously falsely credited for the synthesis of tetrachloroethylene, which in reality, was carbon tetrachloride. While trying to make Faraday's "protochloride of carbon", Regnault found that his compound was different from Faraday's. Victor Regnault stated "According to Faraday, the chloride of carbon boiled around 70 °C (158 °F) to 77 °C (171 °F) degrees Celsius but mine did not begin to boil until 120 °C (248 °F) ".[9]
A few years after its discovery, in the 1840s, Tetrachloroethylene was named Chlorethose by Auguste Laurent. The -ose ending was explained as the fourfold replacement of the hydrogens in ethylene. If only one atom of hydrogen was replaced, the word would end with -ase. By Laurent's logic, vinyl chloride would be named Chlorethase.[10]
Tetrachloroethylene can be made by passing chloroform vapour through a red-hot tube, the side products include hexachlorobenzene and hexachloroethane, as reported in 1886.[11]
Most tetrachloroethylene is produced by high-temperature chlorinolysis of light hydrocarbons. The method is related to Faraday's method since hexachloroethane is generated and thermally decomposes.[12] Side products include carbon tetrachloride, hydrogen chloride, and hexachlorobutadiene.
Several other methods have been developed. When
- ClCH2CH2Cl + 3 Cl2 → Cl2C=CCl2 + 4 HCl
This reaction can be
Worldwide production was about 1 million metric tons (980,000 long tons; 1,100,000 short tons) in 1985.[12]
Although in very small amounts, tetrachloroethylene occurs naturally in volcanoes along with trichloroethylene.[13]
Uses
Tetrachloroethylene is an excellent nonpolar
It is also used to degrease metal parts in the
Historical applications
Tetrachloroethylene 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 of hookworm infestation.[15][16]
Health and safety
Tetrachloroethylene is much less toxic than other chlorinated solvents.[8] The acute and chronic toxicity of tetrachloroethylene is moderate to low. Reports of human injury are uncommon despite its wide usage in dry cleaning and degreasing.[17]
Despite the advantages of tetrachloroethylene, many[who?] have called for its replacement from widespread commercial use. It has been described as a possible "neurotoxicant, liver and
As an anthelmintic, tetrachloroethylene was given orally to approximately fifty thousand people between 1925 and 1943. The most severe side effects were nausea and vomiting due to the irritation of gastric tract. Most reported poisonings were manifestations of its narcotic effects.[19]
Metabolism
Tetrachloroethylene's biological half-life is approximately 3 days.[20] About 98% of the inhaled Tetrachloroethylene is exhaled unchanged and only about 1–3% is metabolised to tetrachloroethylene oxide which rapidly isomerises into trichloroacetyl chloride. Trichloroacetyl chloride hydrolyses to trichloroacetic acid.[21][20]
Carcinogenicity
Tetrachloroethylene has been classified as "probably carcinogenic to humans" (Group 2A) by the International Agency for Research on Cancer (IARC). There is a possibility that it is carcinogenic to humans in long-term exposure, but the evidence is limited since most of the evaluated dry-cleaners had heavy smoking and drinking habits which are known to cause multiple types of cancer.[22] Epidemiological research has been conducted in the dry-cleaning industry because of the widespread use of tetrachloroethylene in the industry since 1960. The evidence demonstrates a positive association between tetrachloroethylene exposure, bladder cancer, non-Hodgkin lymphoma, and multiple myeloma in adults. A review of 109 occupational studies estimated a mean exposure of 59 ppm in dry-cleaning employees. Epidemiological evidence shows that exposure via ingestion or inhalation can increase tumor incidence.[23] Exposure to tetrachloroethylene in a typical dry cleaning shop is considered far below the levels required to cause any risk.[24]
Testing for exposure
Tetrachloroethylene exposure can be evaluated by a breath test, analogous to breath-alcohol measurements. Also, for acute exposures, tetrachloroethylene in expired air can be measured.[25] Tetrachloroethylene can be detected in the breath for weeks following a heavy exposure. Tetrachloroethylene and its metabolite trichloroacetic acid, can be detected in the blood.
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.[26]
Remediation and degradation
In principle, tetrachloroethylene contamination can be remediated by chemical treatment. Chemical treatment involves reducing metals such as iron powder.
Explanatory notes
- ^ Also spelt as perchlorethylene, especially in older texts.
References
- ^ C. Chabrie "General Method for the Preparation of Carbon Fluorides" in Journal - Chemical Society, London. (1890). UK: Chemical Society.
- ^ Justus Liebigs Annalen der Chemie. (1845). Germany: Verlag Chemie. Page 277
- ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0599". National Institute for Occupational Safety and Health (NIOSH).
- ^ Sigma Aldrich Tetrachloroethylene MSDS
- ^ Fischer Scientific Tetrachloroethylene MSDS
- ^ "Tetrachloroethylene". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^ "Compound Summary: Tetrachloroethylene". PubChem. Retrieved 9 September 2020.
- ^ a b Ethel Browning, Toxicity of Industrial Organic Solvents (1953, [ https://archive.org/details/cftri.3112toxicityofindust0000ethe/page/182/mode/1up pages 182-185]
- .
- ^ Transactions of the Pharmaceutical Meetings. (1847). UK: J. Churchill. page 548
- ^ W. Ramsay and S. Young, Jahresberichte, 1886, p. 628
- ^
- PMID 8795309.
- ^ Amos, J. Lawrence (1990). "Chlorinated solvents". In Boundy, Ray H.; Amos, J. Lawrence (eds.). A History of the Dow Chemical Physics Lab : the freedom to be creative. New York and Basel: Marcel Dekker, Inc. pp. 71–79.
- PMID 13787477.
- ^ "Clinical Aspects and Treatment of the More Common Intestinal Parasites of Man (TB-33)". Veterans Administration Technical Bulletin 1946 & 1947. 10: 1–14. 1948.
- ISBN 978-3527306732.
- PMID 33748070.
- ^ Ellen B. Foot, Virginia Apgar and Kingsley Bishop, [https://archive.org/details/sim_anesthesiology_1943-05_4_3/page/283/mode/1up Tetrachlorethylene as an Anesthetic Agent], in Anesthesiology, 1943-05: Vol 4 Iss 3
- ^ a b Biological Monitoring: An Introduction. (1993). page 470
- ^ Toxicological Profile for Tetrachloroethylene: Draft. (1995). U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry.
- ^ "Tetrachloroethylene (IARC Summary & Evaluation, Volume 63, 1995)". www.inchem.org.
- PMID 24531164– via PubMed.
- PMID 19367044.
- ^ "Tetrachloroethylene Toxicity: Section 3.1. Evaluation and Diagnosis | Environmental Medicine | ATSDR". www.atsdr.cdc.gov. 9 February 2021. Retrieved 2 March 2023.
- ^ "SCOEL recommendations". 22 April 2011. Retrieved 22 April 2011.
- PMID 28347952.
- S2CID 23770815.
Further reading
- "Toxicological Profile for Tetrachloroethene". Agency for Toxic Substances and Disease Registry. 1997.
- Doherty, R.E. (2000). "A History of the Production and Use of Carbon Tetrachloride, Tetrachloroethylene, Trichloroethylene and 1,1,1-Trichloroethane in the United States: Part 1 - Historical Background; Carbon Tetrachloride and Tetrachloroethylene". Environmental Forensics. 1 (2): 69–81. S2CID 97680726.
External links
- ATSDR Case Studies in Environmental Medicine: Tetrachloroethylene Toxicity U.S. Department of Health and Human Services
- Tetrachloroethylene (Perchloroethylene) U.S. Department of Health and Human Services
- Australian National Pollutant Inventory (NPI) page
- Sustainable uses and Industry recommendations