1,1,1,2-Tetrafluoroethane(also known asnorflurane(INN),R-134a, Klea 134a,Freon 134a,Forane 134a,Genetron 134a,Green Gas,Florasol 134a,Suva 134a,HFA-134a,orHFC-134a) is ahydrofluorocarbon(HFC) andhaloalkanerefrigerantwith thermodynamic properties similar toR-12 (dichlorodifluoromethane)but with insignificantozone depletion potentialand a lower 100-yearglobal warming potential(1,430, compared to R-12's GWP of 10,900).[1]It has the formula CF3CH2F and aboiling pointof −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are coloredlight blue.[2]A phaseout and transition toHFO-1234yfand other refrigerants, with GWPs similar to CO2,began in 2012 within the automotive market.[3]
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Names | |||
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Preferred IUPAC name
1,1,1,2-Tetrafluoroethane | |||
Other names
HFA-134a
HFC-134a R-134a Norflurane | |||
Identifiers | |||
3D model (JSmol)
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ChEMBL | |||
ChemSpider | |||
DrugBank | |||
ECHA InfoCard | 100.011.252 | ||
EC Number |
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KEGG | |||
PubChemCID
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RTECS number |
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UNII | |||
UN number | 3159 | ||
CompTox Dashboard(EPA)
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Properties | |||
C2H2F4 | |||
Molar mass | 102.032g·mol−1 | ||
Appearance | Colorless gas | ||
Density | 0.00425 g/cm3,gas | ||
Melting point | −103.3 °C (−153.9 °F; 169.8 K) | ||
Boiling point | −26.3 °C (−15.3 °F; 246.8 K) | ||
0.15 wt% | |||
Hazards | |||
Occupational safety and health(OHS/OSH): | |||
Main hazards
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Asphyxiant | ||
GHSlabelling: | |||
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Warning | |||
H280 | |||
P410+P403 | |||
NFPA 704(fire diamond) | |||
Flash point | 250 °C (482 °F; 523 K) | ||
Related compounds | |||
Relatedrefrigerants
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Difluoromethane Pentafluoroethane | ||
Related compounds
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1-Chloro-1,2,2,2-tetrafluoroethane 1,1,1-Trichloroethane | ||
Supplementary data page | |||
1,1,1,2-Tetrafluoroethane (data page) | |||
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).
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Uses
edit1,1,1,2-Tetrafluoroethane is anon-flammablegas used primarily as a "high-temperature" refrigerant for domesticrefrigerationandautomobile air conditioners.These devices began using 1,1,1,2-tetrafluoroethane in the early 1990s as a replacement for the more environmentally harmfulR-12.Retrofit kits are available to convert units that were originally R-12-equipped.
Other common uses include plastic foam blowing, as a cleaning solvent, a propellant for the delivery of pharmaceuticals (e.g.bronchodilators), wine cork removers,gas dusters( "canned air" ), and in air driers for removing the moisture fromcompressed air.1,1,1,2-Tetrafluoroethane has also been used to cool computers in someoverclockingattempts. It is the refrigerant used in plumbing pipe freeze kits. It is also commonly used as a propellant forairsoftairguns. The gas is often mixed with a silicone-based lubricant.
Aspirational and niche applications
edit1,1,1,2-Tetrafluoroethane is also being considered as anorganic solvent,both in liquid andsupercritical fluid.[4][5] [6]
It is used in theresistive plate chamberparticle detectorsin theLarge Hadron Collider.[7][8]It is also used for other types of particle detectors, e.g. somecryogenic particle detectors.[9]It can be used as an alternative tosulfur hexafluorideinmagnesiumsmeltingas ashielding gas.[10]
History and environmental impacts
edit1,1,1,2-Tetrafluoroethane was introduced in the early 1990s as a replacement fordichlorodifluoromethane (R-12),which has massive ozone depleting properties.[11]Even though 1,1,1,2-Tetrafluoroethane has insignificant ozone depletion potential (ozone layer) and negligible acidification potential (acid rain), it has a 100-yearglobal warming potential(GWP) of 1430 and an approximateatmospheric lifetimeof 14 years.[1]Its concentration in the atmosphere and contribution toradiative forcinghave been growing since its introduction. Thus it was included in theIPCC list of greenhouse gases.[12]
R-134a began being phased out from use in theEuropean Union,starting in the mid 2010s, by a directive of 2006, recommending the replacement of gases in air conditioning systems with a GWP above 100.[13]
1,1,1,2-tetrafluoroethane is subject to use restrictions in the US and other countries as well. The Society of Automotive Engineers (SAE) has proposed that it be best replaced by a new fluorochemical refrigerantHFO-1234yf(CF3CF=CH2) in automobile air-conditioning systems.[14]As of model year 2021, newly manufactured light-duty vehicles in the United States no longer use R-134a.[3]
California may also prohibit the sale of canned R-134a to individuals to avoid non-professional recharge of air conditioners.[15]A ban had been in place in Wisconsin since October 1994 under ATCP 136 prohibiting sales of container sizes holding less than 15 lbs of 1,1,1,2-tetrafluoroethane, but this restriction applied only when the chemical was intended to be a refrigerant. However, the ban was lifted in Wisconsin in 2012.[16]During the time that it was active, this Wisconsin-specific ban contained loopholes. For example, it was legal for a person to purchasegas dustercontainers with any amount of the chemical because in that instance the chemical is neither intended to be a refrigerant [16]nor is HFC-134a included in the § 7671a listing of class I and class II substances.[17]
Production and reactions
editTetrafluoroethane is typically made by reactingtrichloroethylenewithhydrogen fluoride:[18]
- CHCl=CCl2+ 4 HF → CF3CH2F + 3 HCl
It reacts with butyllithium to give trifluorovinyl lithium:[19]
- CF3CH2F + 2 BuLi → CF2=CFLi + LiF + 2 BuH
Safety
editMixtures with air of the gas 1,1,1,2-tetrafluoroethane are notflammableat atmospheric pressure and temperatures up to 100 °C (212 °F). However, mixtures with high concentrations of air at elevated pressure and/or temperature can beignited.[20]Contact of 1,1,1,2-tetrafluoroethane with flames or hot surfaces in excess of 250 °C (482 °F) may cause vapordecompositionand the emission oftoxicgases includinghydrogen fluorideandcarbonyl fluoride,[21]however the decomposition temperature has been reported as above 370 °C.[22]1,1,1,2-Tetrafluoroethane itself has anLD50of 1,500 g/m3in rats, making it relatively non-toxic, apart from the dangers inherent toinhalant abuse.Its gaseous form is denser than air and will displace air in the lungs. This can result inasphyxiationif excessively inhaled.[23][24]This contributes to most deaths byinhalant abuse.
Aerosol cans containing 1,1,1,2-tetrafluoroethane, when inverted, become effective freeze sprays. Under pressure, 1,1,1,2-tetrafluoroethane is compressed into a liquid, which upon vaporization absorbs a significant amount ofthermal energy.As a result, it will greatly lower the temperature of any object it contacts as it evaporates.
Medical use
editFor its medical uses, 1,1,1,2-tetrafluoroethane has thegeneric namenorflurane. It is used as propellant for some metered doseinhalers.[25]It is considered safe for this use.[26][27][28]In combination withpentafluoropropane,it is used as a topicalvapocoolantspray for numbingboilsbeforecurettage.[29][30]It has also been studied as a potentialinhalational anesthetic,[31]but it is nonanaesthetic at doses used in inhalers.[26]
See also
editReferences
edit- ^ab"Table 2.14 (Errata). Lifetimes, radiative efficiencies and direct (except for CH4) GWPs relative to CO2".Archived fromthe originalon 6 July 2017.Retrieved11 July2017.
- ^"Example image of a 30 lbs R134a bottle".budgetheating.com.Retrieved26 March2018.
- ^ab"Refrigerant Transition & Environmental Impacts".U.S. Environmental Protection Agency. 6 August 2015.Retrieved1 October2020.
- ^Corr, Stuart (2005). "1,1,1,2-Tetrafluoroethane (R-134a): A Selective Solvent for the Generation of Flavor and Fragrance Ingredients".Natural Flavors and Fragrances.ACS Symposium Series. Vol. 908. p. 41.doi:10.1021/bk-2005-0908.ch003.ISBN0-8412-3904-5.
- ^Abbott, Andrew P.; Eltringham, Wayne; Hope, Eric G.; Nicola, Mazin (2005). "Solubility of unsaturated carboxylic acids in supercritical 1,1,1,2-tetrafluoroethane (HFC 134a) and a methodology for the separation of ternary mixtures".Green Chemistry.7(4): 210.doi:10.1039/B412697A.
- ^Abbott, Andrew P.; Eltringham, Wayne; Hope, Eric G.; Nicola, Mazin (2005)."Hydrogenation in supercritical 1,1,1,2 tetrafluoroethane (HFC 134a)"(PDF).Green Chemistry.7(10): 721.doi:10.1039/B507554H.hdl:2381/604.Archived fromthe original(PDF)on 19 July 2018.Retrieved18 September2019.
- ^Anushree GhoshSTUDY OF GLASS RESISTIVE PLATE CHAMBERS (RPC) AND CALCULATION OF EFFICIENCYArchived7 August 2011 at theWayback Machine.INO Graduate Training Programme DHEP, TIFR, Mumbai.
- ^M. Capeans, I. Glushkov, R. Guida, F. Hahn, S. Haider (CERN, Switzerland)RPC operation at the LHC experiments in an optimized closed loop gas system.Medical Imaging Conference. 25–31 October 2009.
- ^Norbeck, E.; Olson, J. E.; Moeller, A.; Onel, Y. (2006)."Rad Hard Active Media For Calorimeters"(PDF).AIP Conference Proceedings.867:84.Bibcode:2006AIPC..867...84N.doi:10.1063/1.2396941.Archived fromthe original(PDF)on 23 March 2012.
- ^Magnesium recycling in the United States in 1998.(PDF). USGS. Retrieved 21 August 2011.
- ^Franklin J (1993)."The Atmospheric Degradation and Impact of 1,1,1,2-Tetrafluorethane (Hydrofluorocarbon 134a)".Chemosphere.27(8): 1565–1601.Bibcode:1993Chmsp..27.1565F.doi:10.1016/0045-6535(93)90251-Y.
- ^Forster, P.; et al. (2007)."Changes in Atmospheric Constituents and in Radiative Forcing."(PDF).Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.Archived(PDF)from the original on 24 July 2010.
- ^"DIRECTIVE 2006/40/EC relating to emissions from air-conditioning systems in motor vehicles and amending Council Directive 70/156/EEC".eur-lex.europa.eu.17 May 2006.Retrieved29 May2021.
- ^HFO-1234yf A Low GWP Refrigerant For MACArchived27 February 2009 at theWayback Machine.Refrigerants.dupont.com (17 August 2011). Retrieved 21 August 2011.
- ^California restricts use of HFC-134a in cars.27 June 2007. R744.com. Retrieved 21 August 2011.
- ^abChapter ATCP 136. MOBILE AIR CONDITIONERS; RECLAIMING OR RECYCLING REFRIGERANT.State.wi.us. (PDF). Retrieved 21 August 2011.
- ^Class I Ozone-depleting Substances.EPA.gov. Retrieved 21 August 2011.
- ^"Solvay in North America | Solvay"(PDF).
- ^Burdon, James; Coe, Paul L.; Haslock, Iain B.; Powell, Richard L. (1996). "The hydrofluorocarbon 1,1,1,2-tetrafluoroethane (HFC-134a) as a ready source of trifluorovinyllithium".Chemical Communications:49.doi:10.1039/CC9960000049.
- ^DuPont(2004).DuPont HFC-134a— Properties, Uses, Storage, and Handling(PDF)(Report). Archived fromthe original(PDF)on 4 October 2016.Retrieved5 August2016.
- ^Honeywell International(December 2005). "MSDS # GTRN-0047 For Genetron 134aUV".
- ^"SAFETY DATA SHEET according to Regulation (EU) 2015/8301/7 Harp 134a"(PDF).
- ^Alexander D. J.; Libretto S. E. (1995). "An overview of the toxicology of HFA-134a (1,1,1,2-tetrafluoroethane)".Hum. Exp. Toxicol.14(9): 715–20.doi:10.1177/096032719501400903.PMID8579881.S2CID19669317.
- ^G. E. Millward; E. Tschuikow-Roux (1972). "Kinetic analysis of the shock wave decomposition of 1,1,1,2-tetrafluoroethane".The Journal of Physical Chemistry.76(3): 292–298.doi:10.1021/j100647a002.
- ^Sellers, William F. S. (2017)."Asthma pressurised metered dose inhaler performance: Propellant effect studies in delivery systems".Allergy, Asthma & Clinical Immunology.13:30.doi:10.1186/s13223-017-0202-0.PMC5492461.PMID28670327.
- ^abShah, S. B; Hariharan, U; Bhargava, A. K (2015)."Anaesthetic in the garb of a propellant".Indian Journal of Anaesthesia.59(4): 258–260.doi:10.4103/0019-5049.155011.PMC4408662.PMID25937660.
This propellant has been shown to be safe and nonanaesthetic in standard inhaler doses
- ^Huchon, G; Hofbauer, P; Cannizzaro, G; Iacono, P; Wald, F (2000)."Comparison of the safety of drug delivery via HFA- and CFC-metered dose inhalers in CAO".The European Respiratory Journal.15(4): 663–9.doi:10.1034/j.1399-3003.2000.15d07.x.PMID10780756.
- ^"1,1,1,2-Tetrafluoroethane".Occupational Safety & Health Administration.Archived fromthe originalon 3 February 2018.Retrieved3 February2018.
- ^"Norflurane".DrugBank.
- ^"Norflurane-Pentafluoropropane Aerosol, Spray".WebMD.
- ^Shulman M, Sadove MS (1967)."1,1,1,2-tetrafluoroethane: an inhalational agent of intermediate potency".Anesthesia and Analgesia.46(5): 629–635.doi:10.1213/00000539-196709000-00029.S2CID5868484.
External links
edit- International Chemical Safety Card 1281
- European Fluorocarbons Technical Committee (EFCTC)
- MSDS at Oxford University
- Concise International Chemical Assessment Document 11,at inchem.org
- Pressure temperature calculator
- "The Coexisting Curve of the Refrigerant HFC 134a: Some Scaling Models"(PDF).Archived fromthe original(PDF)on 29 September 2006.Retrieved11 September2007.
- R134a 2 phase computer coolingArchived18 June 2008 at theWayback Machine