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) andhaloalkanerefrigerant with thermodynamic properties similar toR-12 (dichlorodifluoromethane) but with insignificantozone depletion potential and 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 point of −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are coloredlight blue.[2] A phaseout and transition toHFO-1234yf and other refrigerants, with GWPs similar to CO2, began in 2012 within the automotive market.[3]
1,1,1,2-Tetrafluoroethane is anon-flammable gas used primarily as a "high-temperature" refrigerant for domesticrefrigeration andautomobile 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.
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., inhaler canisters such as forbronchodilators), 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 someoverclocking attempts. It is the refrigerant used in plumbing pipe freeze kits. It is also commonly used as a propellant forairsoft airguns. The gas is often mixed with a silicone-based lubricant.
HFC-134a measured by the Advanced Global Atmospheric Gases Experiment (AGAGE) in the lower atmosphere (troposphere) at stations around the world. Abundances are given as pollution free monthly mean mole fractions inparts-per-trillion.HFC-134a atmospheric concentration since year 1995.
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 duster containers 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]
Mixtures with air of the gas 1,1,1,2-tetrafluoroethane are notflammable 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 beignited.[20] Contact of 1,1,1,2-tetrafluoroethane with flames or hot surfaces in excess of 250 °C (482 °F) may cause vapordecomposition and the emission oftoxic gases includinghydrogen fluoride andcarbonyl fluoride,[21] however the decomposition temperature has been reported as above 370 °C.[22] 1,1,1,2-Tetrafluoroethane itself has anLD50 of 1,500 g/m3 in 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 inasphyxiation if 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.
^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.
^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.
^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.
^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.
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