1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Klea 134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, HFA-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).[1] 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.[2] A phaseout and transition to HFO-1234yf and 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
Freon 134a
Dymel 134a Forane 134a Genetron 134a HFA-134a HFC-134a R-134a Suva 134a Norflurane | |||
Identifiers | |||
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3D model (JSmol)
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ChEMBL |
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ChemSpider |
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DrugBank |
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ECHA InfoCard | 100.011.252 | ||
EC Number |
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KEGG |
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PubChem CID
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RTECS number |
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UNII |
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UN number | 3159 | ||
CompTox Dashboard (EPA)
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Properties | |||
C2H2F4 | |||
Molar mass | 102.032 g·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 | ||
GHS labelling: | |||
Warning | |||
H280 | |||
P410+P403 | |||
NFPA 704 (fire diamond) | |||
Flash point | 250 °C (482 °F; 523 K) | ||
Related compounds | |||
Related refrigerants
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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 their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
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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.
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.
1,1,1,2-Tetrafluoroethane is also being considered as an organic solvent, both in liquid and supercritical fluid.[4][5] [6]
It is used in the resistive plate chamber particle detectors in the Large Hadron Collider.[7][8] It is also used for other types of particle detectors, e.g. some cryogenic particle detectors.[9] It can be used as an alternative to sulfur hexafluoride in magnesium smelting as a shielding gas.[10]
1,1,1,2-Tetrafluoroethane was introduced in the early 1990s as a replacement for dichlorodifluoromethane (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-year global warming potential (GWP) of 1430 and an approximate atmospheric lifetime of 14 years.[1] 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.[12]
R-134a began being phased out from use in the European 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 refrigerant HFO-1234yf (CF3CF=CH2) in automobile air-conditioning systems.[14] By model year 2021, newly manufactured light-duty vehicles in the United States will 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 purchase gas 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]
Tetrafluoroethane is typically made by reacting trichloroethylene with hydrogen fluoride:[18]
It reacts with butyllithium to give trifluorovinyl lithium:[19]
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.[20] 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,[21] however the decomposition temperature has been reported as above 370 °C.[22] 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.[23][24] 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.
For its medical uses, 1,1,1,2-tetrafluoroethane has the generic name norflurane. It is used as propellant for some metered dose inhalers.[25] It is considered safe for this use.[26][27][28] In combination with pentafluoropropane, it is used as a topical vapocoolant spray for numbing boils before curettage.[29][30] It has also been studied as a potential inhalational anesthetic,[31] but it is nonanaesthetic at doses used in inhalers.[26]
This propellant has been shown to be safe and nonanaesthetic in standard inhaler doses