1,1,1,2-Tetrafluoroethane

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1,1,1,2-Tetrafluoroethane
Structure
3-D structure
Names
IUPAC name
1,1,1,2-Tetrafluoroethane
Other names
Dymel 134a
Forane 134a
Genetron 134a
HFA-134a
HFC-134a
R-134a
Suva 134a
Norflurane
Identifiers
811-97-2 YesY
ChemSpider 12577 YesY
EC Number 212-377-0
Jmol 3D model Interactive image
KEGG D05208 YesY
RTECS number KI8842500
UNII DH9E53K1Y8 YesY
  • InChI=1S/C2H2F4/c3-1-2(4,5)6/h1H2 YesY
    Key: LVGUZGTVOIAKKC-UHFFFAOYSA-N YesY
  • InChI=1/C2H2F4/c3-1-2(4,5)6/h1H2
    Key: LVGUZGTVOIAKKC-UHFFFAOYAU
  • FCC(F)(F)F
Properties
CH2FCF3 [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%
Vapor pressure {{{value}}}
Related compounds
Related refrigerants
 Difluoromethane
Pentafluoroethane
Related compounds
 2-Chloro-
1,1,1,2-tetrafluoroethane
1,1,1-Trichloroethane
Supplementary data page
Refractive index (n),
Dielectric constant (εr), etc.
Thermodynamic
data
 Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
YesY verify (what is YesYN ?)
Infobox references

1,1,1,2-tetrafluoroethane, R-134a, Forane 134a, Genetron 134a, Florasol 134a, Suva 134a or HFC-134a, also known as norflurane (INN), is a haloalkane refrigerant with thermodynamic properties similar to R-12 (dichlorodifluoromethane) but with insignificant ozone depletion potential. It has the formula CH2FCF3 and a boiling point of −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are colored light blue.[2] Attempts at phasing out its use as a refrigerant with substances that have lower global warming potentials, such as HFO-1234yf are underway.

Uses

1,1,1,2-Tetrafluoroethane is an inert 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 and retrofit kits are available to convert units that were originally R-12-equipped. Other uses include plastic foam blowing, as a cleaning solvent, a propellant for the delivery of pharmaceuticals (e.g. bronchodilators), wine cork removers, gas dusters 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 also commonly used as a propellant for airsoft airguns. The gas is often mixed with a silicon-based lubricant.

Tetrafluoroethane, when compressed as inside gas duster cans, is a clear liquid which boils when exposed to atmospheric pressure at room temperature (as seen here) and can be extracted from common "canned air" canisters by simply inverting them during use.

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.[3][4] It can also be used as a solvent in organic chemistry, both in liquid and supercritical fluid.[5] It is used in the resistive plate chamber particle detectors in the Large Hadron Collider.[6][7] It is also used for other types of particle detectors, e.g. some cryogenic particle detectors.[8] It can be used as an alternative to sulfur hexafluoride in magnesium smelting as a shielding gas.[9]

1,1,1,2-tetrafluoroethane is also being considered as an alternative to sulfur hexafluoride as a dielectric gas.[10] Its arc-quenching properties are poor, but its dielectric properties are fairly good.

Climate change considerations

Recently, 1,1,1,2-tetrafluoroethane has been subject to use restrictions due to its contribution to climate change.[11] It has a global warming potential of 1300.[12]

United States

The Society of Automotive Engineers (SAE) has proposed 1,1,1,2-tetrafluoroethane (HFC-134a) to be best replaced by a new fluorochemical refrigerant HFO-1234yf (CF3CF=CH2) in automobile air-conditioning systems.[13] California may also prohibit the sale of canned 1,1,1,2-tetrafluoroethane to individuals to avoid non-professional recharge of air conditioners.[14] 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 applies only when the chemical is intended to be a refrigerant. The ban has been lifted in Wisconsin in 2012.[15] It appears, for example, that it is 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 [15] nor is HFC-134a included in the § 7671a listing of class I and class II substances.[16]

History

1,1,1,2-Tetrafluoroethane first appeared in the early 1990s as a replacement for dichlorodifluoromethane (R-12), which has ozone depleting properties.[17] 1,1,1,2-Tetrafluoroethane has been atmospherically modeled for its impact on depleting ozone and as a contributor to global warming. Research suggests that over the past 10 years the concentration of 1,1,1,2-tetrafluoroethane has increased significantly in the Earth's atmosphere, with a recent study revealing a doubling in atmospheric concentration between 2001 and 2004.[18] It has insignificant ozone depletion potential (ozone layer), significant global warming potential (100-yr GWP = 1430)[19] and negligible acidification potential (acid rain). Because of its high GWP, 1,1,1,2-tetrafluoroethane has been banned from use in the European Union, starting with cars in 2011 and phasing out completely by 2017.[20]

Safety

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 halides.[21] 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.[22][23] This is what 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. This can result in frostbite when it contacts skin, as well as blindness upon eye contact.

See also

References

  1. ↑ Global Warming Potentials of ODS Substitutes Ozone Layer Protection US EPA. Epa.gov (2006-06-28). Retrieved on 2011-08-21.
  2. ↑ [1]
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Anushree Ghosh STUDY OF GLASS RESISTIVE PLATE CHAMBERS (RPC) AND CALCULATION OF EFFICIENCY. INO Graduate Training Programme DHEP, TIFR, Mumbai.
  7. ↑ 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.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Magnesium recycling in the United States in 1998. (PDF) . USGS. Retrieved on 2011-08-21.
  10. ↑ Gaseous dielectrics with low global warming potentials – US Patent Application 20080135817 Description. Patentstorm.us (2006-12-12). Retrieved on 2011-08-21.
  11. ↑ European Directive 2006/40/EC relating to emissions from air-conditioning systems in motor vehicles. (PDF) . Retrieved on 2011-08-21.
  12. ↑ Compressed air dusters and environmental concerns. (PDF). Retrieved on 2015-05-26.
  13. ↑ HFO-1234yf A Low GWP Refrigerant For MAC. Refrigerants.dupont.com (2011-08-17). Retrieved on 2011-08-21.
  14. ↑ California restricts use of HFC-134a in cars. 27 June 2007. R744.com. Retrieved on 2011-08-21.
  15. ↑ 15.0 15.1 Chapter ATCP 136. MOBILE AIR CONDITIONERS; RECLAIMING OR RECYCLING REFRIGERANT. State.wi.us. (PDF) . Retrieved on 2011-08-21.
  16. ↑ Class I Ozone-depleting Substances. EPA.gov. Retrieved on 2011-08-21.
  17. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  18. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  19. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  20. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  21. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  22. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  23. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

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