1,1,1-Trichloroethane

1,1,1-Trichloroethane was first reported by Henri Victor Regnault in 1840. Industrially, it is usually produced in a two-step process from vinyl chloride. In the first step, vinyl chloride reacts with hydrogen chloride at 20–50 °C to produce 1,1-dichloroethane:

:{{chem2|H2C\dCHCl}} + HCl → CH{{sub|3}}CHCl{{sub|2}}

This reaction is catalyzed by a variety of Lewis acids, mainly aluminium chloride, iron(III) chloride, or zinc chloride. The 1,1-dichloroethane is then converted to 1,1,1-trichloroethane by reaction with chlorine under ultraviolet irradiation:

:CH{{sub|3}}CHCl{{sub|2}} + Cl{{sub|2}} → CH{{sub|3}}CCl{{sub|3}} + HCl

This reaction proceeds at 80–90% yield, and the hydrogen chloride byproduct can be recycled to the first step in the process. The major side-product is the related compound 1,1,2-trichloroethane, from which the 1,1,1-trichloroethane can be separated by distillation.

A somewhat smaller amount of 1,1,1-trichloroethane is produced from the reaction of 1,1-dichloroethene and hydrogen chloride in the presence of an iron(III) chloride catalyst:

:CH{{sub|2}}=CCl{{sub|2}} + HCl → CH{{sub|3}}CCl{{sub|3}}

1,1,1-Trichloroethane is sold with stabilizers because it is unstable with respect to dehydrochlorination and attacks some metals. Stabilizers comprise up to 8% of the formulation, including acid scavengers (epoxides, amines) and complexants.

1,1,1-Trichloroethane is an excellent solvent for many organic compounds and also one of the least toxic of the chlorinated hydrocarbons. It is generally considered non-polar, but owing to the good polarizability of the chlorine atoms, it is a superior solvent for organic compounds that do not dissolve well in hydrocarbons such as hexane. Prior to the Montreal Protocol, it was widely used for cleaning metal parts and circuit boards, as a photoresist solvent in the electronics industry, as an aerosol propellant, as a cutting fluid additive, and as a solvent for inks, paints, adhesives, and other coatings. 1,1,1-trichloroethane was used to dry-clean leather and suede and it was one of the components of Dow Chemical's "Dowclene" dry cleaning fluid among with tetrachloroethylene, first marketed in the late 1930s. Use of 1,1,1-trichloroethane in dry-cleaning remained until the 1980s, meanwhile tetrachloroethylene is still widely used. 1,1,1-Trichloroethane is also used as an insecticidal fumigant.Morrison, R. D., Murphy, B. L. (2013). Chlorinated Solvents: A Forensic Evaluation. UK Royal Society of Chemistry.

It was also the standard cleaner for photographic film (movie/slide/negatives, etc.). Other commonly available solvents damage emulsion and base (acetone will dissolve triacetate base on most films), and thus are not suitable for this application. The standard replacement, Forane 141 is much less effective, and tends to leave a residue. 1,1,1-Trichloroethane was used as a thinner in correction fluid products such as liquid paper. Many of its applications previously used carbon tetrachloride (which was banned in US consumer products in 1970). In turn, 1,1,1-trichloroethane itself is now being replaced by other solvents in the laboratory.[http://www.norden.org/pub/ebook/2003-516.pdf Use of Ozone Depleting Substances in Laboratories. TemaNord 516/2003] {{webarchive|url=https://web.archive.org/web/20080227052412/http://www.norden.org/pub/ebook/2003-516.pdf |date=2008-02-27}} Phase-out of 1,1,1-Trichloroethane due to ozone depletion lead to a resurgence of the use of trichloroethylene in metal degreasing.

1,1,1-Trichloroethane was one of the volatile organochlorides that have been tried as alternatives to chloroform in anaesthesia.The American Practitioner 1881-01: Volume 23, [https://archive.org/details/sim_american-practitioner_1881-01_23/page/28/mode/1up?q=%22methyl+chloroform%22 page 28]

In the 1880s, it was found to be a safe and strong substitute for chloroformMethyl-Chloroform (1887) in Saint Louis Medical and Surgical Journal, [https://archive.org/details/saintlouismedic08unkngoog/page/n127/mode/1up?q=%22methyl+chloroform%22 page 121] but its production was too expensive and difficult for the era.An introduction to modern therapeutics (1892), Brunton, T. Lauder, [https://archive.org/details/b20406204/page/121/mode/1up?q=%22methyl+chloroform%22 page 122]

In 1880, 1,1,1-trichloroethane was suggested as an anaesthetic. It was first referred to as "methyl-chloroform" in the same year. At the time, the narcotic effects of chloral hydrate were owed to a hypothetical metabolic pathway to chloroform in "alkaline blood". Trichloroethane was studied for its structural similarity to chloral and potential anaesthetic effects. However, trichloroethane did not exhibit any conversion to chloroform in laboratory experiments. The 1,1,2-Trichloroethane (vinyl trichloride) isomer, which lacked a trichloromethyl group, exhibited anaesthetic effects even stronger than the 1,1,1 isomer.On Two New Anaesthetics (1880), The American Journal of Pharmacy 1881-03: Vol 53, [https://archive.org/details/sim_american-journal-of-pharmacy-and-the-sciences_1881-03_53/page/119/mode/1up?q=%22methyl+chloroform%22 pages 119–120]

Although not as toxic as many similar compounds, inhaled or ingested 1,1,1-trichloroethane does act as a central nervous system depressant and can cause effects similar to those of ethanol intoxication, including dizziness, confusion, and, in sufficiently high concentrations, unconsciousness and death.[http://www.atsdr.cdc.gov/toxprofiles/tp70.html Toxicological Profile for 1,1,1-Trichloroethane] {{Webarchive|url=https://web.archive.org/web/20080509103329/http://www.atsdr.cdc.gov/toxprofiles/tp70.html |date=2008-05-09 }}, Agency for Toxic Substances and Disease Registry (ATSDR). 2006 Fatal poisonings and illnesses linked to intentional inhalation of trichloroethane have been reported.{{cite journal

|title = Sudden Death in Adolescents Resulting From the Inhalation of Typewriter Correction Fluid

|journal = JAMA: The Journal of the American Medical Association

|volume = 253

|issue = 11

|pages = 1604–1606

|date = 15 March 1985

|pmid = 3974043

|url = http://jama.ama-assn.org/cgi/content/short/253/11/1604

|quote = We describe four cases of sudden death in adolescents associated with recreational sniffing of typewriter correction fluid occurring during the period 1979 through mid-1984.

|archive-url = https://archive.today/20130223191954/http://jama.ama-assn.org/cgi/content/short/253/11/1604

|archive-date = 2013-02-23

|url-status = live

|access-date = 2010-01-05

|last1 = King

|first1 = Gregory S.

|last2 = Smialek

|first2 = John E.

|last3 = Troutman

|first3 = William G.

|doi = 10.1001/jama.253.11.1604

|url-access= subscription

}}{{cite journal

|title=Fatal cerebral oedema following trichloroethane abuse

|journal=Journal of the Royal Society of Medicine

|volume=83

|issue=8

|pages=533–534

|date=August 1990

|pmid=2231588

|pmc=1292788

|last1=D'costa

|first1=DF

|last2=Gunasekera

|first2=NP

|doi=10.1177/014107689008300823

}}{{cite journal

|title = Fatal inhalation of 1,1,1-trichloroethane

|url = https://archive.org/details/sim_forensic-science-international_1997-06-06_87_2/page/161

|journal = Forensic Science International

|volume = 87

|issue = 2

|pages = 161–165

|date = 6 June 1997

|pmid = 9237378

|doi = 10.1016/S0379-0738(97)00040-6

|last1 = Winekab

|first1 = Charles L.

|last2 = Wahba

|first2 = Wagdy W.

|last3 = Huston

|first3 = Robert

|last4 = Rozin

|first4 = Leon

|quote = A 13-year-old male was found dead in the woods subsequent to 1,1,1-trichloroethane (TCE) inhalation.

}}{{cite journal

|title = Cardiac Effects of Inhaled Typewriter Correction Fluid

|journal = Annals of Internal Medicine

|volume = 110

|issue = 1

|pages = 91–92

|date = 1 January 1989

|pmid = 2908837

|url = http://www.annals.org/cgi/content/abstract/110/1/91-a

|archive-url = https://archive.today/20130414005033/http://www.annals.org/cgi/content/abstract/110/1/91-a

|archive-date = 2013-04-14

|url-status = live

|access-date = 2010-01-05

|doi = 10.7326/0003-4819-110-1-91_2

|last1 = Wodka

|first1 = Richard M.

|last2 = Jeong

|first2 = Erwin W. S.

|url-access= subscription

}}

Prolonged skin contact with the liquid can result in the removal of fats from the skin, resulting in skin irritation.

The International Agency for Research on Cancer places 1,1,1-trichloroethane in Group 2A as a probable carcinogen.{{Cite book |last=IARC |url=https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/1-1-1-Trichloroethane-And-Four-Other-Industrial-Chemicals-2022 |title=1,1,1-Trichloroethane and Four Other Industrial Chemicals |isbn=978-92-832-0197-7 |language=en}}

File:CH3CCl3 mm.png) at stations around the world. Abundances are given as pollution free monthly mean mole fractions in parts-per-trillion.]]

File:BK MC.jpg

1,1,1-Trichloroethane is a fairly potent greenhouse gas with a 100-year global warming potential of 169 relative to carbon dioxide.{{cite journal | vauthors = Hodnebrog Ø, Aamaas B, Fuglestvedt JS, Marston G, Myhre G, Nielsen CJ, Sandstad M, Shine KP, Wallington TJ | title = Updated Global Warming Potentials and Radiative Efficiencies of Halocarbons and Other Weak Atmospheric Absorbers | journal = Reviews of Geophysics | volume = 58 | issue = 3 | pages = e2019RG000691 | date = September 2020 | doi = 10.1029/2019RG000691 | pmid = 33015672 | pmc = 7518032 | bibcode = 2020RvGeo..5800691H }} This is nonetheless less than a tenth that of carbon tetrachloride — which it replaced as a solvent — due to its relatively short atmospheric lifetime of about 5 years.{{cite book |url=https://www.ipcc.ch/report/ar5/wg1/ |contribution= Chapter 8, Table 8.A.1 |title=AR5 Climate Change 2013: The Physical Science Basis |page=733}}

The Montreal Protocol targeted 1,1,1-trichloroethane as a compound responsible for ozone depletion and banned its use beginning in 1996. Since then, its manufacture and use have been phased out throughout most of the world, and its atmospheric concentration has declined substantially.

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• 1,1,2-Trichloro-1,2,2-trifluoroethane

{{Reflist|30em}}

• {{cite journal |last1= Doherty |first1= R.E. |year= 2000 |title= A History of the Production and Use of Carbon Tetrachloride, Tetrachloroethylene, Trichloroethylene and 1,1,1-Trichloroethane in the United States: Part 2 - Trichloroethylene and 1,1,1-Trichloroethane |journal= Environmental Forensics|volume= 1 |issue= 2|pages= 83–93 |doi=10.1006/enfo.2000.0011|bibcode= 2000EnvFo...1...83D |s2cid= 97370778 }}

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