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1,1,1,2-Tetrafluoroethane
Structure
3-D structure
IUPAC name
Other names Genetron 134a
HFA-134a
HFC-134a
R-134a
Suva 134a
Norflurane
Identifiers
CAS number 811-97-2 Yes check.svgY
EC number 212-377-0
RTECS number KI8842500
SMILES
Properties
Molecular formula C2H2F4
Molar mass 102.03 g/mol
Appearance Colorless gas
Density 0.00425 g/cm³, 4.25 Kg/m³, gas
Melting point

-103.3°C (169.85 K)

Boiling point

-26.3°C (246.85 K)

Solubility in water 0.15 wt%
Hazards
MSDS External MSDS
S-phrases (S2), S23, S24/25, S51
NFPA 704
NFPA 704.svg
1
1
1
 
Flash point Non-flammable
Related compounds
Related refrigerants Difluoromethane
Pentafluoroethane
Related compounds 1,1,2,2,2-pentafluoroethane
2-Chloro-
1,1,1,2-tetrafluoroethane

1,1,1-Trichloroethane
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
 Yes check.svgY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

1,1,1,2-Tetrafluoroethane, R-134a, Genetron 134a, Suva 134a or HFC-134a, is a haloalkane refrigerant with thermodynamic properties similar to R-12 (dichlorodifluoromethane), but with less ozone depletion potential. It has the formula CH2FCF3, and a boiling point of −26.3 °C (−15.34 °F).

Contents

Uses

1,1,1,2-Tetrafluoroethane is an inert gas used primarily as a "high-temperature" refrigerant for domestic refrigeration and automobile air conditioners. Other uses include plastic foam blowing, as a cleaning solvent and as a propellant for the delivery of pharmaceuticals (e.g. bronchodilators), gas dusters, and in air driers, for removing the moisture from compressed air. Moisture present in compressed air has a harmful effect on pneumatic systems. 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.

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

Recently, 1,1,1,2-tetrafluoroethane has been subject to use restrictions due to its contribution to climate change. In the EU, it will be banned as from 2011 in all new cars.[1] 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.[2] California may prohibit the sale of canned 1,1,1,2-tetrafluoroethane to individuals to avoid non-professional recharge of air conditioners. A ban has 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.[3] 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 [3] nor is HFC-134a included in the § 7671a listing of class I and class II substances.[4] The chemical has also been banned in mobile air conditioners in the state of California. [5]

History

1,1,1,2-Tetrafluoroethane first appeared in the early 1990s as a replacement for dichlorodifluoromethane (R-12), which has supposed ozone depleting properties.[6] 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 2001–2004.[7] It has insignificant ozone depletion potential (ozone layer), significant global warming potential (GWP = 1300)[8] and negligible acidification potential (acid rain). 1,1,1,2-Tetrafluoroethane is slowly converted to trifluoroacetic acid through a radical reaction in the upper atmosphere and leads to a detectable amount of several ng/L in acid rain in some models.[9]

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.[10] 1,1,1,2-Tetrafluoroethane itself has an LD50 (lethal concentration for 50% of subjects) in rats of 1,500 g/m³, making it relatively non-toxic. However, its gaseous form is denser than air, and will displace air in the lungs. This can result in asphyxiation if excessively inhaled.[11][12]

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.

References

  1. ^ European Directive 2006/40/EC relating to emissions from air-conditioning systems in motor vehicles
  2. ^ HFO-1234yf A Low GWP Refrigerant For MAC
  3. ^ a b State.wi.us
  4. ^ EPA.gov
  5. ^ R744.com
  6. ^ Franklin J (1993). "The Atmospheric Degradation and Impact of 1,1,1,2-Tetrafluorethane (Hydrofluorocarbon 134a)". Chemosphere 27: 1565–1601. doi:10.1016/0045-6535(93)90251-Y.  
  7. ^ "Greenhouse gas monitoring at the Zeppelin station - Annual report 2004 (TA-2110/2005)". Norwegian Institute for Air Research. http://www.r744.com/news/files/NILU-%20exec%20summary%20of%20annual%20report%202004.pdf. Retrieved 2006-01-19.  
  8. ^ IPCC.ch
  9. ^ von Sydow L, Grimvall AB, Borén HB, Laniewski K, Nielsen AT (2000). "Natural Background Levels of Trifluoroacetate in Rain and Snow". Enviro Sci Technol 34: 3115–3118. doi:10.1021/es9913683.  
  10. ^ Honeywell International (December 2005). MSDS # GTRN-0047 For Genetron 134aUV.  
  11. ^ Alexander D. J, Libretto S. E. (1995). "An overview of the toxicology of HFA-134a (1,1,1,2-tetrafluoroethane)". Hum. Exp. Toxicol. 14: 715–20. doi:10.1177/096032719501400903.  
  12. ^ 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.  

See also

External links

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1,1,1,2-Tetrafluoroethane
Identifiers
CAS number 811-97-2 Y
ChemSpider 12577
UNII DH9E53K1Y8 Y
EC number 212-377-0
RTECS number KI8842500
SMILES
InChI
InChI key
Properties
Molecular formula C2H2F4
Molar mass 102.03 g/mol
Appearance Colorless gas
Density 0.00425 g/cm³, 4.25 Kg/m³, gas
Melting point

-103.3°C (169.85 K)

Boiling point

-26.3°C (246.85 K)

Solubility in water 0.15 wt%
Hazards
MSDS External MSDS
S-phrases (S2), S23, S24/25, S51
NFPA 704
1
1
1
Flash point 250 °C (482 °F)
Related compounds
Related refrigerants Difluoromethane
Pentafluoroethane
Related compounds 1,1,2,2,2-pentafluoroethane
2-Chloro-
1,1,1,2-tetrafluoroethane

1,1,1-Trichloroethane
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
 Y (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

1,1,1,2-Tetrafluoroethane, R-134a, Genetron 134a, Suva 134a or HFC-134a, is a haloalkane refrigerant with thermodynamic properties similar to R-12 (dichlorodifluoromethane), but with less ozone depletion potential. It has the formula CH2FCF3, and a boiling point of −26.3 °C (−15.34 °F).

Contents

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 1990's 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 and as a propellant for the delivery of pharmaceuticals (e.g. bronchodilators), 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.

canisters by simply inverting them during use.]]

Recently, 1,1,1,2-tetrafluoroethane has been subject to use restrictions due to its contribution to climate change. In the EU, it will be banned as from 2011 in all new cars.[1] 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.[2] California may also prohibit the sale of canned 1,1,1,2-tetrafluoroethane to individuals to avoid non-professional recharge of air conditioners. [3] A ban has 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.[4] 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 [4] nor is HFC-134a included in the § 7671a listing of class I and class II substances.[5]

History

1,1,1,2-Tetrafluoroethane first appeared in the early 1990s as a replacement for dichlorodifluoromethane (R-12), which has ozone depleting properties.[6] 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 2001–2004.[7] It has insignificant ozone depletion potential (ozone layer), significant global warming potential (100-yr GWP = 1430)[8] and negligible acidification potential (acid rain).

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.[9] 1,1,1,2-Tetrafluoroethane itself has an LD50 (lethal concentration for 50% of subjects) in rats of 1,500 g/m³, making it relatively non-toxic. However, its gaseous form is denser than air, and will displace air in the lungs. This can result in asphyxiation if excessively inhaled.[10][11]

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.

References

  1. ^ European Directive 2006/40/EC relating to emissions from air-conditioning systems in motor vehicles
  2. ^ HFO-1234yf A Low GWP Refrigerant For MAC
  3. ^ R744.com
  4. ^ a b State.wi.us
  5. ^ EPA.gov
  6. ^ Franklin J (1993). [Expression error: Unexpected < operator "The Atmospheric Degradation and Impact of 1,1,1,2-Tetrafluorethane (Hydrofluorocarbon 134a)"]. Chemosphere 27: 1565–1601. doi:10.1016/0045-6535(93)90251-Y. 
  7. ^ "Greenhouse gas monitoring at the Zeppelin station - Annual report 2004 (TA-2110/2005)". Norwegian Institute for Air Research. http://www.r744.com/news/files/NILU-%20exec%20summary%20of%20annual%20report%202004.pdf. Retrieved 2006-01-19. 
  8. ^ Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D.W. Fahey, J. Haywood, J. Lean, D.C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga, M. Schulz and R. Van Dorland (2007). "Changes in Atmospheric Constituents and in Radiative Forcing.". Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf. 
  9. ^ Honeywell International (December 2005). [Expression error: Unexpected < operator MSDS # GTRN-0047 For Genetron 134aUV]. 
  10. ^ Alexander D. J, Libretto S. E. (1995). [Expression error: Unexpected < operator "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. 
  11. ^ G. E. Millward, E. Tschuikow-Roux (1972). [Expression error: Unexpected < operator "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. 

See also

External links


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