Carbon tetrachloride
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| Carbon tetrachloride | |
|---|---|
| IUPAC name | Carbon tetrachloride Tetrachloromethane |
| Other names | Benziform, Carbon chloride, Methane tetrachloride, Perchloromethane, Carbon tet, Benzinoform, Tetraform, Tetrasol, Freon 10, Halon 104, UN 1846 |
| Identifiers | |
| CAS number | |
| PubChem | |
| EINECS number | |
| KEGG | |
| ChEBI | |
| RTECS number | FG4900000 |
| SMILES | C(Cl)(Cl)(Cl)Cl |
| InChI | InChI=1/CCl4/c2-1(3,4)5 |
| Properties | |
| Molecular formula | CCl4 |
| Molar mass | 153.82 g/mol |
| Appearance | Colorless liquid |
| Density | 1.5842 g/cm3, liquid 1.831 g.cm-3 at -186 °C (solid) |
| Melting point |
-22.92 °C (250 K) |
| Boiling point |
76.72 °C (350 K) |
| Solubility in water | 8 mg/l at 20 °C |
| log P | 2.64 |
| Vapor pressure | 11.94 kPa at 20 °C |
| kH | 365 kJ.mol-1 at 24.8 °C |
| Structure | |
| Crystal structure | Monoclinic |
| Molecular shape | Tetrahedral |
| Hazards | |
| EU classification | Toxic (T), Carc. Cat. 2B, Dangerous for the environment (N) |
| NFPA 704 |
|
| S-phrases | (S1/2), S23, S36/37, S45, S59, S61 |
| Flash point | Non flammable |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references | |
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Overview
Carbon tetrachloride, also known by many other names (see Table) is the chemical compound with the formula CCl4. It is a reagent in synthetic chemistry and was formerly widely used in fire extinguishers and as a precursor to refrigerants. It is a colorless liquid with a "sweet" smell that can be detected at low levels.
Both carbon tetrachloride and tetrachloromethane are acceptable names under IUPAC nomenclature, depending on whether it is seen as an inorganic or an organic compound. Colloquially, it is called "carbon tet".
Production
Carbon tetrachloride was originally synthesised in 1839 by reaction of chloroform with chlorine, but the most common synthesis is now chlorination of carbon disulfide at 105 to 130 °C:
CCl4 can also be prepared from methane via the reaction:
It is also a byproduct in the synthesis of dichloromethane and chloroform.
Properties
In the carbon tetrachloride molecule, four chlorine atoms are positioned symmetrically as corners in a tetrahedral configuration joined to a carbon atom, in the center, by single covalent bonds. Because of this symmetrical geometry, the molecule has no net dipole moment; that is, CCl4 is non-polar. As a solvent, it is well suited to dissolving other non-polar compounds, fats and oils. It is somewhat volatile, giving off vapors having a smell characteristic of other chlorinated solvents, somewhat similar to the tetrachloroethylene smell reminiscent of dry cleaners' shops.
Solid tetrachloromethane has 2 allotropes: crystaline II below -47.5 °C (225.6 K) and crystaline I above -47.5 °C.[1]
At -47.3 °C it has monoclinic crystal structure with space group C2/c and lattice constants a = 20.3, b = 11.6, c = 19.9 (.10-1 nm), β = 111°.[2]
Uses
In the early 20th century, carbon tetrachloride was widely used as a dry cleaning solvent, as a refrigerant, and in fire extinguishers[3]. However, once it became apparent that carbon tetrachloride exposure had severe adverse health effects, safer alternatives such as tetrachloroethylene were found for these applications, and its use in these roles declined from about 1940 onward. Carbon tetrachloride persisted as a pesticide to kill insects in stored grain, but in 1970, it was banned in consumer products in the United States.
Prior to the Montreal Protocol, large quantities of carbon tetrachloride were used to produce the freon refrigerants R-11 (trichlorofluoromethane) and R-12 (dichlorodifluoromethane). However, these refrigerants are now believed to play a role in ozone depletion and have been phased out. Carbon tetrachloride is still used to manufacture less destructive refrigerants.
Carbon tetrachloride has also been used in the detection of neutrinos.
Reactivity
Carbon tetrachloride has practically no flammability at lower temperatures. Under high temperatures in air, it forms poisonous phosgene.
Because it has no C-H bonds, carbon tetrachloride does not easily undergo free-radical reactions. Hence it is a useful solvent for halogenations either by the elemental halogen, or by a halogenation reagent such as N-bromosuccinimide.
In organic chemistry, carbon tetrachloride serves as a source of chlorine in the Appel reaction.
As a solvent
It is used as a solvent in synthetic chemistry research, but because of its adverse health effects, it is no longer commonly used, and chemists generally try to substitute it with other solvents. It is sometimes useful as a solvent for infrared spectroscopy because there are no significant absorption bands > 1600 cm-1. Because carbon tetrachloride does not have any hydrogen atoms, it was historically used in proton NMR spectroscopy. However, carbon tetrachloride is toxic, and its dissolving power is low[4]. Its use has been largely superseded by deuterated solvents, which offer superior solvating properties and allow for deuterium lock by the spectrometer.
Safety
Exposure to high concentrations of carbon tetrachloride (including vapor) can affect the central nervous system, degenerate the liver[5] and kidneys[6] and may result (after prolonged exposure) in coma and even death[7]. Chronic exposure to carbon tetrachloride can cause liver[8][9] and kidney damage and could result in cancer[10] More information can be found in Material safety data sheets.
Carbon tetrachloride is also both ozone-depleting[11] and a greenhouse gas[12]. However, since 1992[13] its atmospheric concentrations have been in decline for the reasons described above (see also the atmospheric time-series figure).
See also
- Haloalkane
- Halomethane
- Chloromethane
- Dichloromethane
- Chloroform
- Tetrafluoromethane
- Tetrabromomethane
- Carbon tetraiodide (Tetraiodomethane)
References
- ↑ http://webbook.nist.gov/cgi/cbook.cgi?ID=C56235&Units=SI&Mask=4#Thermo-Phase
- ↑ F. Brezina, J. Mollin, R. Pastorek, Z. Sindelar. Chemicke tabulky anorganickych sloucenin (Chemical tables of inorganic compounds). SNTL, 1986.
- ↑ 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" (1): 69 - 81. doi:10.1006/enfo.2000.0010.
- ↑ Introduction to Nuclear Magnetic Resonance Spectroscopy, Michigan State University
- ↑ WF Seifert, A Bosma, A Brouwer, HF Hendriks, PJ (1994). "Vitamin A deficiency potentiates carbon tetrachloride-induced liver fibrosis in rats". Hepatology 19: 193-201.
- ↑ Liu KX, Kato Y, Yamazaki M, Higuchi O, Nakamura T, Sugiyama Y. (1993). "Decrease in the hepatic clearance of hepatocyte growth factor in carbon tetrachloride-intoxicated rats". Hepatology 17: 651-60.
- ↑ Recknagel R.O., Glende E.A., Dolak J.A., Waller R.L. (1989). "Mechanism of Carbon-tetrachloride Toxicity". Pharmacology Therapeutics (43): 139-154. doi:10.1016/0163-7258(89)90050-8.
- ↑ Recknagel RO (1967). "Carbon tetrachloride Hepatotoxicity". Pharmacological Reviews 19 (2): 145.
- ↑ Masuda Y (2006). "Learning toxicology from carbon tetrachloride-induced hepatotoxicity". Yakugaku Zasshi -Journal of the Pharmaceutical Society of Japan 126 (10): 885-899.
- ↑ Rood AS, McGavran PD, Aavenson JW, et al. (2001). "Stochastic estimates of exposure and cancer risk from carbon tetrachloride released to the air from the Rocky Flats Plant". Risk Analysis 21 (4): 675-695.
- ↑ Fraser P. (1997). "Chemistry of stratospheric ozone and ozone depletion". Australian Meteorological Magazine 46 (3): 185-193.
- ↑ Evans WFJ, Puckrin E (1996). "A measurement of the greenhouse radiation associated with carbon tetrachloride (CCl4)". Geophysical Research Letters 23 (14): 1769-1772.
- ↑ Walker, S. J., R. F. Weiss & P. K. Salameh (2000). "Reconstructed histories of the annual mean atmospheric mole fractions for the halocarbons CFC-11, CFC-12, CFC-113 and carbon tetrachloride". Journal of Geophysical Research 105: 14285—14296.
External links
- International Chemical Safety Card 0024
- NIOSH Pocket Guide to Chemical Hazards 0107
- IARC Summaries & Evaluations Vol. 71 (1999)
- IARC Monograph: "Carbon Tetrachloride"
- Toxicological profile for carbon tetrachloride
- Environmental health criteria for carbon tetrachloride
- Carbon tetrachloride MSDS at Hazardous Chemical Database
- MSDS at Oxford University
- Transformation of tetrachloromethane to dichloromethane and carbon dioxide by Acetobacterium woodii
- Involvement of cytochromes in the anaerobic biotransformation of tetrachloromethane by Shewanella putrefaciens 200
- Substance profile at ntp.niehs.nih.gov
cs:Tetrachlormethan da:Tetraklorkulstof de:Tetrachlormethanid:Karbon tetraklorida it:Tetracloruro di carbonio lv:Tetrahlorogleklis lt:Anglies tetrachloridas hu:Szén-tetraklorid nl:Tetrachloormethaansk:Tetrachlórmetán fi:Hiilitetrakloridi sv:Koltetraklorid uk:Тетрахлорметан
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
