Carbon tetrachloride, also known by many other names (such as carbon tet for short and tetrachloromethane, also recognised by the IUPAC), is a chemical compound with the chemical formula CCl4. It is a non-flammable, dense, colourless liquid with a chloroform-like sweet odour that can be detected at low levels. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, an anthelmintic and a cleaning agent, but has since been phased out because of environmental and safety concerns. Exposure to high concentrations of carbon tetrachloride can affect the central nervous system and degenerate the liver and kidneys. Prolonged exposure can be fatal.
In the carbon tetrachloride molecule, four chlorineatoms are positioned symmetrically as corners in a tetrahedral configuration joined to a central carbon atom by single covalent bonds. Because of this symmetric geometry, CCl4 is non-polar. Methane gas has the same structure, making carbon tetrachloride a halomethane. As a solvent, it is well suited to dissolving other non-polar compounds such as fats and oils. It can also dissolve iodine. It is volatile, giving off vapors with an odor characteristic of other chlorinated solvents, somewhat similar to the tetrachloroethylene odor reminiscent of dry cleaners' shops.
Solid tetrachloromethane has two polymorphs: crystalline II below −47.5°C (225.6 K) and crystalline I above −47.5°C.<ref>Template:Cite web</ref> At −47.3°C it has monoclinic crystal structure with space group C2/c and lattice constantsa = 20.3, b = 11.6, c = 19.9 (.10−1 nm), β = 111°.<ref name="chtas">F. Brezina, J. Mollin, R. Pastorek, Z. Sindelar. Chemicke tabulky anorganickych sloucenin (Chemical tables of inorganic compounds). SNTL, 1986.</ref>
Despite being generally inert, carbon tetrachloride can undergo various reactions. Hydrogen or an acid in the presence of an iron catalyst can reduce carbon tetrachloride to chloroform, dichloromethane, chloromethane and even methane.<ref>Template:Cite journal</ref> When its vapours are passed through a red-hot tube, carbon tetrachloride dechlorinates to tetrachloroethylene and hexachloroethane.<ref>"Carbonic Dichloride". Tidy, C. M. (1887). Handbook of modern chemistry, inorganic and organic. UK: Smith, Elder & Company. p. 215</ref>
This was once one of the main uses of carbon tetrachloride, as R-11 and R-12 were widely used as refrigerants.
An alcohol solution of potassium hydroxide decomposes it to potassium chloride and potassium carbonate in water:<ref>Wislicenus, J., Strecker, A., Hodgkinson, W. R. E. (1882). Adolph Strecker's Short Text-book of Organic Chemistry. USA: D. Appleton.</ref>
Carbon tetrachloride was originally synthesized in 1820 by Michael Faraday, who named it "protochloride of carbon", by decomposition of hexachloroethane ("perchloride of carbon") which he synthesized by chlorination of ethylene.<ref>Template:Cite book</ref><ref>Turner, Edward. Elements of Chemistry: Including the Recent Discoveries and Doctrines of the Science. United Kingdom, John Taylor, 1834. Page 247</ref> The protochloride of carbon has been previously misidentified as tetrachloroethylene because it can be made with the same reaction of hexachloroethane. Later in the 19th century, the name "protochloride of carbon" was used for tetrachloroethylene, and carbon tetrachloride was called "bichloride of carbon" or "perchloride of carbon". Henri Victor Regnault developed another method to synthesise carbon tetrachloride from chloroform, chloroethane or methanol with excess chlorine in 1839.<ref name=grahamwatts/>
Kolbe made carbon tetrachloride in 1845 by passing chlorine over carbon disulfide through a porcelain tube.<ref name=grahamwatts>Graham, T., Watts, H. (1850). Elements of Chemistry: Including the Applications of the Science in the Arts. USA: Baillière.</ref> Prior to the 1950s, carbon tetrachloride was manufactured by the chlorination of carbon disulfide at 105 to 130 °C:<ref name=Ross/>
The production often utilizes by-products of other chlorination reactions, such as from the syntheses of dichloromethane and chloroform. Higher chlorocarbons are also subjected to this process named "chlorinolysis":
The production of carbon tetrachloride has steeply declined since the 1980s because of environmental concerns and the decreased demand for CFCs, which were derived from carbon tetrachloride. In 1992, production in the U.S./Europe/Japan was estimated at 720,000 tonnes.<ref name=Ross>Manfred Rossberg, Wilhelm Lendle, Gerhard Pfleiderer, Adolf Tögel, Eberhard-Ludwig Dreher, Ernst Langer, Heinz Jaerts, Peter Kleinschmidt, Heinz Strack, Richard Cook, Uwe Beck, Karl-August Lipper, Theodore R. Torkelson, Eckhard Löser, Klaus K. Beutel, "Chlorinated Hydrocarbons" in Ullmann's Encyclopedia of Industrial Chemistry, 2006 Wiley-VCH, Weinheim. Template:Doi</ref> In the 2010s, the total amount of CCl4 produced and imported into the US annually was under 70,000 tonnes.<ref>Template:Cite web</ref>
Natural occurrence
Carbon tetrachloride was discovered along with chloromethane and chloroform in oceans, marine algae and volcanoes.<ref>Template:Cite journal</ref> Natural emissions of carbon tetrachloride are insignificant compared to anthropogenic sources; for example, the Momotombo volcano in Nicaragua emits carbon tetrachloride at a flux of 82 grams per year while the global industrial emissions were at 2 × 1010 grams per year.<ref name="natural" />
Carbon tetrachloride was found in red algae, specifically Asparagopsis taxiformis and Asparagopsis armata.<ref>Gribble, G. (2012). Progress in the Chemistry of Organic Natural Products. Austria: Springer Vienna.</ref> It was detected in Southern Californian ecosystems, salt lakes of the Kalmykian steppe and a common liverwort in the Czech Republic.<ref name="natural">Naturally Occurring Organohalogen Compounds. (2023). Springer Nature Switzerland.</ref>
Safety
At high temperatures in air, it decomposes or burns to produce poisonous phosgene. This was a common problem when carbon tetrachloride was used as a fire extinguisher<ref name="Burke">Template:Cite book</ref> and there have been deaths due to its conversion to phosgene reported.<ref name="Fieldner Katz Kinney 1920">Template:Cite journal</ref>
Consumption of alcohol increases the toxic effects of carbon tetrachloride and may cause more severe organ damage, such as acute renal failure, in heavy drinkers. The doses that can cause mild toxicity to non-drinkers can be fatal to drinkers.<ref name=toxprofile>Toxicological Profile for Carbon Tetrachloride. (2005). USA: Agency for Toxic Substances and Disease Registry.</ref>
The effects of carbon tetrachloride on human health and the environment have been assessed under REACH in 2012 in the context of the substance evaluation by France.<ref>Template:Cite web</ref>
In 2008, a study of common cleaning products found the presence of carbon tetrachloride in "very high concentrations" (up to 101 mg/m3) as a result of manufacturers' mixing of surfactants or soap with sodium hypochlorite (bleach).<ref>
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Prior to being phased out due to toxicity and environmental impact, carbon tetrachloride was widely used as a dry cleaning solvent, as a refrigerant, and in lava lamps.<ref>Template:Cite journal</ref> In the last case, carbon tetrachloride is a key ingredient that adds weight to the otherwise buoyant wax.
One speciality use of carbon tetrachloride was in stamp collecting, to reveal watermarks on postage stamps without damaging them. A small amount of the liquid is placed on the back of a stamp, sitting in a black glass or obsidian tray. The letters or design of the watermark can then be seen clearly. Today, this is done on lit tables without using carbon tetrachloride.
Being a good solvent for many materials (such as grease and tar), carbon tetrachloride was widely used as a cleaning fluid for nearly 70 years. It is nonflammable and nonexplosive and did not leave any odour on the cleaned material, unlike gasoline, which was also used for cleaning at the time. It was used as a "safe" alternative to gasoline. It was first marketed as Katharin, in the early 1890s<ref name=recommended/><ref>Neueste Erfindungen und Erfahrungen Auf Den Gebieten Der Praktischen Technik, Elektrotechnik, Der Gewerbe, Industrie, Chemie, Der Land und Hauswirthschaft. (1895). Austria: (n.p.).</ref> and as Benzinoform later.
German advertisement stamp for Benzinoform (carbon tetrachloride) stain remover, 1912
Carbon tetrachloride was recommended for regularly cleaning the type slugs of typewriters in office settings in the 1940s.<ref>Template:Cite journal</ref>
Carbon tetrachloride was the first chlorinated solvent to be used in dry-cleaning and was used until the 1950s.<ref name=drycleaning/> It had the downsides of being corrosive to the dry-cleaning equipment and causing illness among dry-cleaning operators, and was replaced by less toxic and overall safer solvents such as trichloroethylene, tetrachloroethylene<ref name="drycleaning">"DRY CLEANING IARC"</ref> and methyl chloroform (trichloroethane).<ref>Health and Safety Guide for Laundries and Dry Cleaners. (1975) U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Division of Technical Services.</ref>
Carbon tetrachloride was also used as an ingredient in dry shampoos due to its solvent properties and quick evaporation from 1903 until the 1930s, when it was discontinued due to health and safety concerns. Several women had fainted from its fumes during the hair wash at the hairdressers, and electric fans were used to blow the fumes away. In 1909, a baronet's 29-year-old daughter, Helenora Elphinstone-Dalrymple, died after having her hair shampooed with carbon tetrachloride.<ref>Pharmaceutical Journal: A Weekly Record of Pharmacy and Allied Sciences. (1909). UK: J. Churchill.</ref><ref>Meeker, R., Hamilton, A. (1915). Industrial Poisons Used in the Rubber Industry. U.S. Government Printing Office.</ref>
It is assumed that carbon tetrachloride was still used as a dry cleaning solvent in North Korea as of 2006.<ref>Report of the TEAP, May 2006 Progress Report. (2006). Kenya: United Nations Environment Programme Ozone Secretariat.</ref>
Medical uses
Anaesthetic and analgesic
Carbon tetrachloride was briefly used as a volatile inhalation anaesthetic and analgesic for intense menstruation pains and headaches in the mid-19th century.<ref name=p302>"The Tetrachloride of Carbon as an Anaesthetic", Dr Protheroe Smith, British Journal of Dental Science and Prosthetics (1867). UK: J. P. Segg & Company, page 302</ref> Its anaesthetic effects were known as early as 1847 or 1848.<ref>On the Anaesthetic Use of Terchloride and Protochloride of Carbon The Lancet. UK, J. Onwhyn, 1848.</ref><ref>Mr Nunneley on Anaesthesia and Anaesthetic Substances Edinburgh medical and surgical journal (1849). UK</ref>
It was introduced as a safer alternative to chloroform by the doctor Protheroe Smith in 1864.<ref>"A New Anaesthetic", British Journal of Dental Science and Prosthetics (1867). UK: J. P. Segg & Company, page 239</ref> In December 1865, the Scottish obstetrician who discovered the anaesthetic effects of chloroform on humans, James Young Simpson, had experimented with carbon tetrachloride as an anaesthetic.<ref name=Bichloride>Notes on the anaesthetic properties of the Bichloride of Carbon by Arthur Ernest Sansom, Transactions of the Obstetrical Society of London. (1867) UK: Longmans, Green and Company.</ref> Simpson named the compound "Chlorocarbon" for its similarity to chloroform. His experiments involved injecting carbon tetrachloride into two women's vaginas. Simpson orally consumed carbon tetrachloride and described it as having "the same effect as swallowing a capsule of chloroform".<ref>Pages 170-173, "Anaesthetic and Sedative Properties of Bichloride of Carbon, or Chlorocarbon" (December 1865), Simpson, J. Y., Anaesthesia, Hospitalism, Hermaphroditism, and a Proposal to Stamp Out Small-pox and Other Contagious Diseases. (1871( UK: Adam and Charles Black.</ref>
Because of the higher amount of chlorine atoms (compared to chloroform) in its molecule, carbon tetrachloride has a stronger anaesthetic effect than chloroform and required a smaller amount.<ref name=p302/> Its anaesthetic action was likened to ether, rather than the related chloroform.<ref name=Bichloride/> It is less volatile than chloroform, therefore it was more difficult to apply and needed warm water to evaporate.<ref name=Bichloride/> Its smell has been described as "fruity",<ref name=Bichloride/> quince-like<ref name=PSmith>Protheroe Smith, Dental Cosmos. (1867). USA: S. S. White Dental Manufacturing Company, page 673</ref> and "more pleasant than chloroform",<ref name=p302/> and had a "pleasant taste".<ref name=Bichloride/> Carbon tetrachloride for anaesthetic use was made by the chlorination of carbon disulfide. It was used on at least 50 patients, of which most were women in labour.<ref>"The Tetrachloride of Carbon as an Anaesthetic", Dr Protheroe Smith, British Journal of Dental Science and Prosthetics (1867). UK: J. P. Segg & Company, page 260</ref> During anaesthesia, carbon tetrachloride has caused such violent muscular contractions and negative effects on the heart in some patients that it had to be replaced with chloroform or ether.<ref name=Bichloride/><ref name="Andrews">Am J Dent Sci. 1868 Jan; 1(9): 462–463.
"Trial of Tetrachloride of Carbon as an Anaesthetic.—Dangerous Effects" E. Andrews
[1]</ref> Such use was experimental and the anaesthetic use of carbon tetrachloride never gained popularity due to its potential toxicity.
Parasite medication
No hay que desesperarse, la Necatorina salva (do not despair, Necatorina saves) Advertisement for Merck's Necatorina, Colombia, 1942
The veterinary doctor Maurice Crowther Hall (1881–1938) discovered in 1921 that carbon tetrachloride was highly effective as an anthelmintic in eradicating hookworm via ingestion. In one of the clinical trials of carbon tetrachloride, it was tested on criminals to determine its safety for use on humans.<ref>Browning, E. (1940). Modern Drugs in General Practice.</ref> Beginning in 1922, capsules of pure carbon tetrachloride were marketed by Merck under the name Necatorina (variants include Neo-necatorina and Necatorine). Necatorina was used as a medication against parasitic diseases in humans. This medication was most prevalently used in Latin American countries.<ref>Tropical Diseases Bulletin (1927) UK: Bureau of Hygiene and Tropical Diseases.</ref><ref>Taeger, H. (2013) Die Klinik der entschädigungspflichtigen Berufskrankheiten. Germany: Springer Berlin Heidelberg.</ref> Its toxicity was not well understood at the time and toxic effects were attributed to impurities in the capsules rather than carbon tetrachloride itself.<ref>Tropical Diseases Bulletin (1925) UK: Bureau of Hygiene and Tropical Diseases.</ref> Due to carbon tetrachloride's toxicity, tetrachloroethylene (which was also investigated by Hall in 1925) replaced its use as an anthelmintic by the 1940s.<ref>Manson-Bahr, P. H., Manson, P. (1954). Manson's Tropical Diseases: A Manual of the Diseases of Warm Climates.</ref>
A brass Pyrene carbon tetrachloride fire extinguisherA Red Comet brand glass globe ("fire grenade") containing carbon tetrachloride
Between 1902 and 1908, carbon tetrachloride-based fire extinguishers began to appear in the United States, years after Europe.<ref name=recommended/>
In 1910, the Pyrene Manufacturing Company of Delaware filed a patent to use carbon tetrachloride to extinguish fires.<ref>Template:US patent, filed April 5, 1910.</ref> The liquid was vaporized by the heat of combustion and extinguished flames, an early form of gaseous fire suppression. At the time it was believed the gas displaced oxygen in the area near the fire, but later research found that the gas inhibited the chemical chain reaction of the combustion process.Template:Citation needed
In 1911, Pyrene patented a small, portable extinguisher that used the chemical.<ref>Template:US patent, filed Jan 7, 1911.</ref> The extinguisher consisted of a brass bottle with an integrated hand-pump that was used to expel a jet of liquid toward the fire. As the container was unpressurized, it could easily be refilled after use.<ref>Template:Cite web
</ref> Carbon tetrachloride was suitable for liquid and electrical fires and the extinguishers were often carried on aircraft or motor vehicles. However, as early as 1920, there were reports of fatalities caused by the chemical when used to fight a fire in a confined space.<ref name="Fieldner Katz Kinney 1920"/>
In the first half of the 20th century, another common fire extinguisher was a single-use, sealed glass globe, a "fire grenade, " filled with carbon tetrachloride or salt water. The bulb could be thrown at the base of the flames to quench the fire. The carbon tetrachloride type could also be installed in a spring-loaded wall fixture with a solder-based restraint. When the solder melted by high heat, the spring would either break the globe or launch it out of the bracket, allowing the extinguishing agent to be automatically dispersed into the fire.<ref>Template:Cite book</ref>
Since carbon tetrachloride freezes at –23 °C, the fire extinguishers would contain only 89–90% carbon tetrachloride and 10% trichloroethylene (m.p. –85 °C) or chloroform (m.p. –63 °C) for lowering the extinguishing mixture's freezing point down to temperatures as low as –45 °C. The extinguishers with 10% trichloroethylene would contain 1% carbon disulfide as a stabiliser.<ref name=recommended>Hazards of Carbon Tetrachloride Fire Extinguishers: Recommended Practices Number 3. USA, The Council, 1967.</ref>
Another carbon tetrachloride fumigant preparation mixture contained acrylonitrile. Carbon tetrachloride reduced the flammability of the mixture. Most common trade names for the preparation were Acritet, Carbacryl and Acrylofume.<ref>COMMERCIAL PRODUCTS Morgan, D. P. (1996). Recognition and Management of Pesticide Poisonings. (n.p.): DIANE Publishing Company.</ref> The most common preparation, Acritet, was prepared with 34 percent acrylonitrile and 66 percent carbon tetrachloride.<ref>Hearings, Reports and Prints of the Senate Committee on Government Operations (1964). U.S. Government Printing Office.</ref><ref>Plant Protection and Quarantine Treatment Manual. (1976). U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine Programs.</ref>
Society and culture
The French writer René Daumal intoxicated himself by inhalation of carbon tetrachloride which he used to kill the beetles he collected, to "encounter other worlds" by voluntarily plunging himself into intoxications close to comatose states.<ref name=Libe2011>Template:Cite web</ref>
Australian YouTuber Tom of Explosions&Fire and Extractions&Ire made a video on extracting carbon tetrachloride from an old fire extinguisher in 2019,<ref>Template:Cite web</ref> and later experimenting with it by mixing it with sodium,<ref>Template:Cite web</ref> and the chemical gained a fan base called "Tet Gang" on social media (especially on Reddit). The channel owner later used carbon tetrachloride-themed designs in the channel's merch.
In the Ramones song "Carbona Not Glue" released in 1977, the narrator says that huffing the vapours of Carbona, a carbon tetrachloride-based stain remover, was better than huffing glue. They later removed the song from the album as Carbona was a corporate trademark.<ref>Bessman, Jim (1993). Ramones: An American Band. St. Martin's Griffin. p74.</ref>
Famous deaths from carbon tetrachloride poisoning
Evalyn Bostock (1917–1944), British actress who died from accidentally drinking carbon tetrachloride after mistaking it for her drink while working in a photographic darkroom.<ref>Template:Cite web</ref>
Harry Edwards (1887–1952), an American director who died from carbon tetrachloride poisoning shortly after directing his first television production.<ref>Template:Cite book</ref>
Zilphia Horton (1910–1956), American musician and activist who died from accidentally drinking a glass full of carbon tetrachloride-based typewriter cleaning fluid that she mistook for water.<ref>Template:Cite book</ref>
Margo Jones (1911–1955), American stage director who was exposed to the fumes of carbon tetrachloride that was used to clean off paint from a carpet. She died a week later from kidney failure.<ref>Template:Cite news</ref>
Jim Beck (1919–1956), American record producer, died after exposure to carbon tetrachloride fumes while cleaning recording equipment.<ref>Certificate of Death: James A. Beck, Texas Department of Health, Bureau of Vital Statistics, File #24027</ref>
CCl4 measured by the Advanced Global Atmospheric Gases Experiment (AGAGE) in the lower atmosphere (troposphere) at stations around the world. Abundances are given as pollution-free monthly mean mole fractions in parts-per-trillion.
Hemispheric and Global mean concentrations of CCl4 (NOAA/ESRL).
Time-series of atmospheric concentrations of CCl4 (Walker et al., 2000).
CCl4 measured by the Advanced Global Atmospheric Gases Experiment (AGAGE) in the lower atmosphere (troposphere) at stations around the world. Abundances are given as pollution-free monthly mean mole fractions in parts-per-trillion.
Hemispheric and Global mean concentrations of CCl4 (NOAA/ESRL).
Time-series of atmospheric concentrations of CCl4 (Walker et al., 2000).
