2-Chloro-1,1-difluoroethylene

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2-Chloro-1,1-difluoroethylene
2-Chloro-1,1-difluoroethene.png
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.006.024 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 206-625-7
PubChem CID
UNII
  • InChI=1S/C2HClF2/c3-1-2(4)5/h1H
    Key: HTHNTJCVPNKCPZ-UHFFFAOYSA-N
  • C(=C(F)F)Cl
Properties
C2HClF2
Molar mass 98.48 g·mol−1
Melting point −138.5 °C (−217.3 °F; 134.7 K) [1]
Boiling point −17.7 °C (0.1 °F; 255.5 K)
Related compounds
Other anions
2-Bromo-1,1-difluoroethene
Related compounds
 1-Chloro-1,2-difluoroethene (Z) and (E) isomers (R 1122a);
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

2-Chloro-1,1-difluoroethene (also known as R 1122, u-HCFC-1122 or HCFO-1122) is a toxic unsaturated hydrochlorofluorocarbon which can be written as CF2=CHCl. The HCFO portion of the name stands for hydrochlorofluoroolefin . Another constitutional isomer of it, 1-chloro-1,2-difluoroethylene, is known as HCFO-1122a. [2]

Contents

Formation

One way to make HCFO-1122 by way of dehydrochlorination, is to heat HCFC-132b to 600°C, preferably with some carbon tetrachloride to get a 70% yield.

CH2ClCClF2 → CHCl=CF2 + HCl [3]

A lower yield results if HCFC-132a (1,1-Dichloro-2,2-difluoroethane) is used:

CHCl2CHF2 → CHCl=CF2 + HCl [3]

When trying to make HFC-134a from HCFC-133a, some HCFO-1122 is produced as a side product by way of dehydrofluorination. [3]

CF3CH2Cl → CHCl=CF2 + HF [3] (low yield)

Properties

Shape and size

2-Chloro-1,1-difluoroethene has a flat shape with all atoms in the same plane. The two fluorine atoms can be distinguished by whether one is closer to hydrogen or chlorine F(H) or F(Cl). The bond lengths are: C=C 1.303 Å, C-F(H) 1.321 Å, C-F(Cl) 1.320 Å, C-Cl 1.731 Å, C-H 1.083 Å. For bond angles: ∠CCF(H) 123.4°, ∠CCF(Cl) 126.1°, ∠CCH 128.3°, ∠CCCl 121°. [4]

Spectrum

The infrared spectrum includes strong absorption bands at v10 at 751.1 cm−1, v5 at 971.5 and 970.2 cm−1, v4 at 1200.7 cm−1, v3 at 1341.7 cm−1, and v2 at 1747.5 cm−1. [5] Weaker absorption bands are at v7 at 578.0 and 577.4 cm−1, v6 at 844.9and 842.8 cm−1 and v1 at 3135.9 cm−1. [5] An estimate for radiative forcing potential is 0.098 W m2 ppbv−1 and global warming potential is between 1.5 and 4.5 on 100 year time frame. [5] The lifetime in Earth's atmosphere is only 10 to 30 days mitigating the effect of pollution. [5]

Occurrence

2-Chloro-1,1-difluoroethene may be a contaminant in HFC-134a. [6] It can form by the elimination of HCl or HF from other HCFCs like HCFC-133a. CF3CH2Cl → CF2=CHCl + HF. It can be removed from the mixture by various physical processes such as absorption, or chemical processes, that fluorinate, reduce or oxidise it. [7] An example specification for medical use of HFC-134a requires under 5 ppm of HCFC-1122. [8]

Humans that have been anesthetised by halothane, convert some in the body to 2-chloro-1,1-difluoroethene and then exhale it. [9]

Reactions

When irradiated by ultraviolet light at 192 nm, 2-Chloro-1,1-difluoroethene splits off hydrogen chloride to make a carbene: (difluorovinylidene) CF2=CHCl → CF2=C: + HCl. [10] Difluorovinylidene does not convert to difluoroacetylene (FC≡CF), but instead survives and reacts with other molecules. [11] Also HF can be eliminated to yield chlorofluoroacetylene (ClC≡CF). [12]

2-Chloro-1,1-difluoroethene can be removed from HFC-134a by oxidation with potassium permanganate. [13] Alternately oxidation can occur with hydrogen peroxide. Fluoridation can occur with HF with a chromium trioxide catalyst, producing CF3CH2Cl. With fluorine around −60°C it forms CF3CHClF. [14]

An argon complex with the molecule is known. The argon atom is out of the plane of the other atoms, on the side with the chlorine atom. [4]

When it is heated with cyclopentadiene at 170°C, bicyclic norbornene derivatives are produced. [15]

Wen heated with hydrogen, it is dechlorinated, and becomes the saturated 1,1-difluoroethane. [16]

Trichlorosilane reacts by adding across the double bond, mostly yielding trichloro-(2,2-difluoroethyl)silane. As 2-chloro-1,1-difluoroethene levels increase, more of trichloro-(2-chloro-2,2-difluoroethyl)silane and trichloro-(2-chloro-1,1-difluoroethyl)silane are produced. [17]

Use

2-Chloro-1,1-difluoroethene is an intermediate in the manufacture of fluorosurfactants, fluorine-containing textile finishing agents, organic silicon fluorine modified resins and other fine chemicals containing fluorine. [5]

Related Research Articles

<span class="mw-page-title-main">Chlorofluorocarbon</span> Class of organic compounds

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane.

<span class="mw-page-title-main">Haloalkane</span> Group of chemical compounds derived from alkanes containing one or more halogens

The haloalkanes are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. They are used as flame retardants, fire extinguishants, refrigerants, propellants, solvents, and pharmaceuticals. Subsequent to the widespread use in commerce, many halocarbons have also been shown to be serious pollutants and toxins. For example, the chlorofluorocarbons have been shown to lead to ozone depletion. Methyl bromide is a controversial fumigant. Only haloalkanes that contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a non-ozone layer depleter. For more information, see Halomethane. Haloalkane or alkyl halides are the compounds which have the general formula "RX" where R is an alkyl or substituted alkyl group and X is a halogen.

<span class="mw-page-title-main">Refrigerant</span> Substance in a refrigeration cycle

A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated because of their toxicity and flammability and the contribution of CFC and HCFC refrigerants to ozone depletion and that of HFC refrigerants to climate change.

<span class="mw-page-title-main">Halomethane</span> Halogen compounds derived from methane

Halomethane compounds are derivatives of methane with one or more of the hydrogen atoms replaced with halogen atoms. Halomethanes are both naturally occurring, especially in marine environments, and human-made, most notably as refrigerants, solvents, propellants, and fumigants. Many, including the chlorofluorocarbons, have attracted wide attention because they become active when exposed to ultraviolet light found at high altitudes and destroy the Earth's protective ozone layer.

<span class="mw-page-title-main">Hydrofluorocarbon</span> Synthetic organic compounds

Hydrofluorocarbons (HFCs) are synthetic organic compounds that contain fluorine and hydrogen atoms, and are the most common type of organofluorine compounds. Most are gases at room temperature and pressure. They are frequently used in air conditioning and as refrigerants; R-134a (1,1,1,2-tetrafluoroethane) is one of the most commonly used HFC refrigerants. In order to aid the recovery of the stratospheric ozone layer, HFCs were adopted to replace the more potent chlorofluorocarbons (CFCs), which were phased out from use by the Montreal Protocol, and hydrochlorofluorocarbons (HCFCs) which are presently being phased out. HFCs replaced older chlorofluorocarbons such as R-12 and hydrochlorofluorocarbons such as R-21. HFCs are also used in insulating foams, aerosol propellants, as solvents and for fire protection.

In chemistry, trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane are replaced by halogen atoms. Trihalomethanes with all the same halogen atoms are called haloforms. Many trihalomethanes find uses in industry as solvents or refrigerants. Some THMs are also environmental pollutants, and a few are considered carcinogenic.

1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Klea 134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, HFA-134a, or HFC-134a) is a hydrofluorocarbon (HFC) and haloalkane refrigerant with thermodynamic properties similar to R-12 (dichlorodifluoromethane) but with insignificant ozone depletion potential and a lower 100-year global warming potential (1,430, compared to R-12's GWP of 10,900). It has the formula CF3CH2F and a boiling point of −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are colored light blue. A phaseout and transition to HFO-1234yf and other refrigerants, with GWPs similar to CO2, began in 2012 within the automotive market.

Fluoroform, or trifluoromethane, is the chemical compound with the formula CHF3. It is a hydrofluorocarbon as well as being a part of the haloforms, a class of compounds with the formula CHX3 with C3v symmetry. Fluoroform is used in diverse applications in organic synthesis. It is not an ozone depleter but is a greenhouse gas.

<span class="mw-page-title-main">2,2-Dichloro-1,1,1-trifluoroethane</span> Chemical compound

2,2-Dichloro-1,1,1-trifluoroethane or HCFC-123 is considered as an alternative to CFC-11 in low pressure refrigeration and HVAC systems, and should not be used in foam blowing processes or solvent applications. It is also the primary component of the Halotron I fire-extinguishing mixture.

Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, refrigerants, and reagents in catalysis. In addition to these applications, some organofluorine compounds are pollutants because of their contributions to ozone depletion, global warming, bioaccumulation, and toxicity. The area of organofluorine chemistry often requires special techniques associated with the handling of fluorinating agents.

1,1,2-Trichloro-1,2,2-trifluoroethane, also called trichlorotrifluoroethane or CFC-113, is a chlorofluorocarbon. It has the formula Cl2FC−CClF2. This colorless, volatile liquid is a versatile solvent.

<span class="mw-page-title-main">Fluorine perchlorate</span> Chemical compound

Fluorine perchlorate, also called perchloryl hypofluorite is the rarely encountered chemical compound of fluorine, chlorine, and oxygen with the chemical formula ClO
4F or FOClO
3. It is an extremely unstable gas that explodes spontaneously and has a penetrating odor.

<span class="mw-page-title-main">Hydrofluoroolefin</span> Class of chemical compounds

Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compounds are of interest as refrigerants. Unlike traditional hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), which are saturated, HFOs are olefins, otherwise known as alkenes.

<span class="mw-page-title-main">1,1-Difluoroethylene</span> Chemical compound

1,1-Difluoroethylene, also known as vinylidene fluoride, is a hydrofluoroolefin. This colorless, flammable gas is a difluorinated derivative of ethylene. Global production in 1999 was approximately 33,000 metric tons. It is primarily used in the production of fluoropolymers such as polyvinylidene fluoride and FKM.

<span class="mw-page-title-main">Fluorochemical industry</span> Industry dealing with chemicals from fluorine

The global market for chemicals from fluorine was about US$16 billion per year as of 2006. The industry was predicted to reach 2.6 million metric tons per year by 2015. The largest market is the United States. Western Europe is the second largest. Asia Pacific is the fastest growing region of production. China in particular has experienced significant growth as a fluorochemical market and is becoming a producer of them as well. Fluorite mining was estimated in 2003 to be a $550 million industry, extracting 4.5 million tons per year.

1,2-Difluoroethane is a saturated hydrofluorocarbon containing an atom of fluorine attached to each of two carbons atoms. The formula can be written CH2FCH2F. It is an isomer of 1,1-difluoroethane. It has a HFC name of HFC-152 with no letter suffix. When cooled to cryogenic temperatures it can have different conformers, gauche and trans. In the liquid form these are about equally abundant and easily interconvert. As a gas it is mostly the gauche form.

Alan K. Brisdon is a British chemist and a Senior Lecturer in the Department of Chemistry at The University of Manchester. His research in general is based on fluorine chemistry, including on HCFCs, fluorine-containing organometallic systems, fluorophosphines and fluorine-containing materials, such as ionic liquids and fluorographenes.

<span class="mw-page-title-main">1,2-Dichloro-1,1,2-trifluoroethane</span> Chemical compound

1,2-Dichloro-1,1,2-trifluoroethane is a volatile liquid chlorofluoroalkane composed of carbon, hydrogen, chlorine and fluorine, and with structural formula CClF2CHClF. It is also known as a refrigerant with the designation R-123a.

<span class="mw-page-title-main">Tetrachloro-1,1-difluoroethane</span> Chemical compound

Tetrachloro-1,1-difluoroethane or 1,1,1,2-tetrachloro-2,2-difluoroethane, Freon 112a, R-112a, or CFC-112a is an asymmetric chlorofluorocarbon isomer of tetrachloro-1,1-difluoroethane with formula CClF2CCl3. It contains ethane substituted by four chlorine atoms and two fluorine atoms. With a boiling point of 91.5°C it is the freon with second highest boiling point.

<span class="mw-page-title-main">1,1-Dichlorotetrafluoroethane</span> Chemical compound

1,1-Dichlorotetrafluoroethane is a chlorofluorocarbon also known as CFC-114a or R114a by American Society of Heating, Refrigerating, and Air Conditioning Engineers. It has two chlorine atoms on one carbon atom and none on the other. It is one of two isomers of dichlorotetrafluoroethane, the other being 1,2-dichlorotetrafluoroethane, also known as CFC-114.

References

  1. ↑ "SynQuest Labs, Inc". synquestlabs.com.
  2. ↑ "2903450010 1,1,1,2-Tétrafluoroéthane (HFC-134a)". www.douane.gouv.fr (in French).
  3. 1 2 3 4 Sicard, Alexandre J.; Baker, R. Tom (9 September 2020). "Fluorocarbon Refrigerants and their Syntheses: Past to Present". Chemical Reviews. 120 (17): 9164–9303. doi:10.1021/acs.chemrev.9b00719. PMID   32809811. S2CID   221180753.
  4. 1 2 Leung, Helen O.; Marshall, Mark D.; Messinger, Joseph P.; Knowlton, Gregory S.; Sundheim, Kathryn M.; Cheung-Lau, Jasmina C. (1 November 2014). "The microwave spectra and molecular structures of 2-chloro-1,1-difluoroethylene and its complex with the argon atom". Journal of Molecular Spectroscopy. 305: 25–33. Bibcode:2014JMoSp.305...25L. doi:10.1016/j.jms.2014.09.011.
  5. 1 2 3 4 5 Pietropolli Charmet, Andrea; Ceselin, Giorgia; Stoppa, Paolo; Tasinato, Nicola (24 January 2022). "The Spectroscopic Characterization of Halogenated Pollutants through the Interplay between Theory and Experiment: Application to R1122". Molecules. 27 (3): 748. doi: 10.3390/molecules27030748 . PMC   8839295 . PMID   35164013.
  6. ↑ 张, 永科; 赵, 景婵; 郭, 治安; 张, 彦凤; 韩, 冰 (2007). "医用HFC-134a中微量杂质的定性、定量分析" [Qualitative and Quantitative Analyses of Micro-impurities in Medical HFC-134a]. 应用化学. 24 (11). doi:10.3969/j.issn.1000-0518.2007.11.027.
  7. ↑ Manzer, L.E. (March 1992). "An overview of the commercial development of chlorofluorocarbon (CFC) alternatives". Catalysis Today. 13 (1): 13–22. doi:10.1016/0920-5861(92)80183-N.
  8. ↑ Noakes, Tim (December 2002). "Medical aerosol propellants". Journal of Fluorine Chemistry. 118 (1–2): 35–45. doi:10.1016/S0022-1139(02)00191-4.
  9. ↑ Sharp, J. Howard; Trudell, James R.; Cohen, Ellis N. (1 January 1979). "Volatile Metabolites and Decomposition Products of Halothane In Man". Anesthesiology. 50 (1): 2–8. doi: 10.1097/00000542-197901000-00002 . PMID   760598. S2CID   27245452.
  10. ↑ Huang, Yibo; Gordon, Robert J. (22 January 1997). "The ultraviolet photodissociation dynamics of 2-chloro-1,1-difluoroethylene". The Journal of Chemical Physics. 106 (4): 1418–1420. Bibcode:1997JChPh.106.1418H. doi:10.1063/1.473290.
  11. ↑ Brahms, John C.; Dailey, William P. (May 1990). "Difluoropropadienone as a source of difluorovinylidene and difluorodiazoethene". Journal of the American Chemical Society. 112 (10): 4046–4047. doi:10.1021/ja00166a056.
  12. ↑ Martínez-Núñez, Emilio; Vázquez, Saulo (8 March 2005). "Quasiclassical trajectory calculations on the photodissociation of CF2CHCl at 193nm: Product energy distributions for the HF and HCl eliminations". The Journal of Chemical Physics. 122 (10): 104316. Bibcode:2005JChPh.122j4316M. doi: 10.1063/1.1859276 . PMID   15836324.
  13. ↑ Manzer, L. E. (6 July 1990). "The CFC-Ozone Issue: Progress on the Development of Alternatives to CFCs". Science. 249 (4964): 31–35. Bibcode:1990Sci...249...31M. doi:10.1126/science.249.4964.31. PMID   17787623. S2CID   11822992.
  14. ↑ Guglielmo, Giorgio; Gambaretto, Giampaolo (22 November 1994). "Process for purifying fluoroethanes and chlorofluoroethanes".
  15. ↑ Jacobson, Barry M.; Bartlett, Paul D. (March 1973). "Cycloaddition. XV. Competing mechanisms in the reactions of cyclopentadiene with trifluoroethylene and 2-chloro-1,1-difluoroethylene". The Journal of Organic Chemistry. 38 (5): 1030–1041. doi:10.1021/jo00945a035.
  16. ↑ Lacher, J. R.; Kianpour, A.; Oetting, F.; Park, J. D. (1956). "Reaction calorimetry. The hydrogenation of organic fluorides and chlorides". pp. 1500–1508.
  17. ↑ Bevan, William I.; Haszeldine, Robert N.; Middleton, John; Tipping, Anthony E. (1974). "Polyfluoroalkyl compounds of silicon. Part XII. Reactions of trichlorosilane with 2-chloro- and 2-bromo-1,1-difluoroethylene". Journal of the Chemical Society, Dalton Transactions (21): 2305. doi:10.1039/DT9740002305.
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