1,1,1,2-Tetrafluoroethane

1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 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).[2] 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.[3] A phaseout and transition to HFO-1234yf and other refrigerants, with GWPs similar to CO2, began in 2012 within the automotive market.[4]

1,1,1,2-Tetrafluoroethane
Structure
3-D structure
Names
Preferred IUPAC name
1,1,1,2-Tetrafluoroethane
Other names
Freon 134a
Dymel 134a
Forane 134a
Genetron 134a
HFA-134a
HFC-134a
R-134a
Suva 134a
Norflurane
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.011.252 Edit this at Wikidata
EC Number
  • 212-377-0
KEGG
RTECS number
  • KI8842500
UNII
UN number 3159
  • InChI=1S/C2H2F4/c3-1-2(4,5)6/h1H2 checkY
    Key: LVGUZGTVOIAKKC-UHFFFAOYSA-N checkY
  • FCC(F)(F)F
Properties
CF3CH2F[1]
Molar mass 102.03 g/mol
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
Asphyxiant
GHS labelling:
GHS04: Compressed Gas
Warning
H280
P410+P403
NFPA 704 (fire diamond)
1
0
1
Flash point 250 °C (482 °F; 523 K)
Related compounds
Related refrigerants
Difluoromethane
Pentafluoroethane
Related compounds
2-Chloro-
1,1,1,2-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 their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)
Infobox references

UsesEdit

1,1,1,2-Tetrafluoroethane is a non-flammable gas used primarily as a "high-temperature" refrigerant for domestic refrigeration and automobile air conditioners. These devices began using 1,1,1,2-tetrafluoroethane in the early 1990s as a replacement for the more environmentally harmful R-12. Retrofit kits are available to convert units that were originally R-12-equipped.

 
Boiling of Tetrafluoroethane liquid when exposed to normal atmospheric pressure and temperature.

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 from compressed air. 1,1,1,2-Tetrafluoroethane has also been used to cool computers in some overclocking attempts. It is the refrigerant used in plumbing pipe freeze kits. It is also commonly used as a propellant for airsoft airguns. The gas is often mixed with a silicone-based lubricant.

Aspirational and niche applicationsEdit

1,1,1,2-Tetrafluoroethane is also being considered as an organic solvent suitable for extraction of flavor and fragrance compounds, as a possible alternative to other organic solvents and supercritical carbon dioxide.[5][6] It can also be used as a solvent in organic chemistry, both in liquid and supercritical fluid.[7] It is used in the resistive plate chamber particle detectors in the Large Hadron Collider.[8][9] It is also used for other types of particle detectors, e.g. some cryogenic particle detectors.[10] It can be used as an alternative to sulfur hexafluoride in magnesium smelting as a shielding gas.[11]

1,1,1,2-Tetrafluoroethane is also being considered as an alternative to sulfur hexafluoride as a dielectric gas.[12] Its arc-quenching properties are poor, but its dielectric properties are fairly good.

History and environmental impactsEdit

1,1,1,2-Tetrafluoroethane was introduced in the early 1990s as a replacement for dichlorodifluoromethane (R-12), which has massive ozone depleting properties.[13] Even though it has insignificant ozone depletion potential (ozone layer) and negligible acidification potential (acid rain), it has a 100-year global warming potential (GWP) of 1430 and an approximate atmospheric lifetime of 14 years.[2] Its concentration in the atmosphere and contribution to radiative forcing have been growing since its introduction. Thus it was included in the IPCC list of greenhouse gases.[14]

 
HFC-134a atmospheric concentration since year 1995.

R-134a was consequently banned from use in the European Union, starting with cars in 2011, by a directive of 2006 banning gases in air conditioning systems with a GWP above 100. [15]

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 refrigerant HFO-1234yf (CF3CF=CH2) in automobile air-conditioning systems.[16] By model year 2021, newly manufactured light-duty vehicles in the United States will no longer use R-134a.[4]

California may also prohibit the sale of canned R-134a to individuals to avoid non-professional recharge of air conditioners.[17] 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.[18] During the time that it was active, this Wisconsin-specific ban contained loopholes. For example, it was legal for a person to purchase gas duster containers with any amount of the chemical because in that instance the chemical is neither intended to be a refrigerant [18] nor is HFC-134a included in the § 7671a listing of class I and class II substances.[19]

Production and reactionsEdit

Tetrafluoroethane is typically made by reacting trichloroethylene with hydrogen fluoride:[20]

CHCl=CCl2 + 4 HF → CF3CH2F + 3 HCl

It reacts with butyllithium to give trifluorovinyl lithium:[21]

CF3CH2F + 2 BuLi → CF2=CFLi + LiF + 2 BuH

SafetyEdit

 
R-134a cylinder

Mixtures with air of the gas 1,1,1,2-tetrafluoroethane are not flammable at atmospheric pressure and temperatures up to 100 °C (212 °F). However, mixtures with high concentrations of air at elevated pressure and/or temperature can be ignited.[22] Contact of 1,1,1,2-tetrafluoroethane with flames or hot surfaces in excess of 250 °C (482 °F) may cause vapor decomposition and the emission of toxic gases including hydrogen fluoride and carbonyl fluoride,[23] however the decomposition temperature has been reported as above 370 °C,.[24] 1,1,1,2-Tetrafluoroethane itself has an LD50 of 1,500 g/m3 in rats, making it relatively non-toxic, apart from the dangers inherent to inhalant abuse. Its gaseous form is denser than air and will displace air in the lungs. This can result in asphyxiation if excessively inhaled.[25][26] This contributes to most deaths by inhalant 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 of thermal energy. As a result, it will greatly lower the temperature of any object it contacts as it evaporates.

 
Freon 134a refrigerant for car AC

Medical useEdit

For its medical uses, 1,1,1,2-tetrafluoroethane has the generic name norflurane. It is used as propellant for some metered dose inhalers.[27] It is considered safe for this use.[28][29][30] In combination with pentafluoropropane, it is used as a topical vapocoolant spray for numbing boils before curettage.[31][32] It has also been studied as a potential inhalational anesthetic,[33] but it is nonanaesthetic at doses used in inhalers.[28]

See alsoEdit

ReferencesEdit

  1. ^ Global Warming Potentials of ODS Substitutes Ozone Layer Protection US EPA. Epa.gov (28 June 2006). Retrieved 21 August 2011.
  2. ^ a b "Table 2.14 (Errata). Lifetimes, radiative efficiencies and direct (except for CH4) GWPs relative to CO2". Archived from the original on 6 July 2017. Retrieved 11 July 2017.
  3. ^ "Example image of a 30 lbs R134a bottle". budgetheating.com. Retrieved 26 March 2018.
  4. ^ a b "Refrigerant Transition & Environmental Impacts". U.S. Environmental Protection Agency. 6 August 2015. Retrieved 1 October 2020.
  5. ^ 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. 908. p. 41. doi:10.1021/bk-2005-0908.ch003. ISBN 0-8412-3904-5.
  6. ^ 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.
  7. ^ 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 from the original (PDF) on 19 July 2018. Retrieved 18 September 2019.
  8. ^ Anushree Ghosh STUDY OF GLASS RESISTIVE PLATE CHAMBERS (RPC) AND CALCULATION OF EFFICIENCY Archived 7 August 2011 at the Wayback Machine. INO Graduate Training Programme DHEP, TIFR, Mumbai.
  9. ^ 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.
  10. ^ 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 from the original (PDF) on 23 March 2012.
  11. ^ Magnesium recycling in the United States in 1998. (PDF). USGS. Retrieved 21 August 2011.
  12. ^ Gaseous dielectrics with low global warming potentials – US Patent Application 20080135817 Description Archived 13 October 2012 at the Wayback Machine. Patentstorm.us (12 December 2006). Retrieved 21 August 2011.
  13. ^ 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.
  14. ^ 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.
  15. ^ "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. Retrieved 29 May 2021.
  16. ^ HFO-1234yf A Low GWP Refrigerant For MAC Archived 27 February 2009 at the Wayback Machine. Refrigerants.dupont.com (17 August 2011). Retrieved 21 August 2011.
  17. ^ California restricts use of HFC-134a in cars. 27 June 2007. R744.com. Retrieved 21 August 2011.
  18. ^ a b Chapter ATCP 136. MOBILE AIR CONDITIONERS; RECLAIMING OR RECYCLING REFRIGERANT. State.wi.us. (PDF). Retrieved 21 August 2011.
  19. ^ Class I Ozone-depleting Substances. EPA.gov. Retrieved 21 August 2011.
  20. ^ "Solvay in North America | Solvay" (PDF).
  21. ^ 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.
  22. ^ DuPont (2004). DuPont HFC-134a— Properties, Uses, Storage, and Handling (PDF) (Report). Archived from the original (PDF) on 4 October 2016. Retrieved 5 August 2016.
  23. ^ Honeywell International (December 2005). "MSDS # GTRN-0047 For Genetron 134aUV".
  24. ^ "SAFETY DATA SHEET according to Regulation (EU) 2015/8301/7 Harp® 134a" (PDF).
  25. ^ 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. PMID 8579881. S2CID 19669317.
  26. ^ 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.
  27. ^ 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. PMC 5492461. PMID 28670327.
  28. ^ a b Shah, 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. PMC 4408662. PMID 25937660. This propellant has been shown to be safe and nonanaesthetic in standard inhaler doses
  29. ^ 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. PMID 10780756.
  30. ^ "1,1,1,2-Tetrafluoroethane". Occupational Safety & Health Administration.
  31. ^ "Norflurane". DrugBank.
  32. ^ "Norflurane-Pentafluoropropane Aerosol, Spray". WebMD.
  33. ^ 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. S2CID 5868484.

External linksEdit