3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||102.03 g/mol|
|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)|
|Safety data sheet||See: data page|
|GHS Signal word||Warning|
|NFPA 704 (fire diamond)|
|Flash point||250 °C (482 °F; 523 K)|
|Supplementary data page|
|Refractive index (n),|
Dielectric constant (εr), etc.
|UV, IR, NMR, MS|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Freon 134a, Forane 134a, Genetron 134a, 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). 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. A phaseout and transition to HFO-1234yf and other refrigerants, with GWPs similar to CO2, began in year 2012 within the automotive market.
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.
Aspirational and niche applications
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. It can also be used as a solvent in organic chemistry, both in liquid and supercritical fluid. It is used in the resistive plate chamber particle detectors in the Large Hadron Collider. It is also used for other types of particle detectors, e.g. some cryogenic particle detectors. It can be used as an alternative to sulfur hexafluoride in magnesium smelting as a shielding gas.
1,1,1,2-Tetrafluoroethane is also being considered as an alternative to sulfur hexafluoride as a dielectric gas. Its arc-quenching properties are poor, but its dielectric properties are fairly good.
History and environmental impacts
1,1,1,2-Tetrafluoroethane first appeared in the early 1990s as a replacement for dichlorodifluoromethane (R-12), which has ozone depleting properties. It has insignificant ozone depletion potential (ozone layer) and negligible acidification potential (acid rain). It has a 100-year global warming potential of 1430 and an approximate atmospheric lifetime of 14 years. Its concentration in the atmosphere and contribution to radiative forcing have been growing since its introduction. It is included in the IPCC list of greenhouse gases.
1,1,1,2-tetrafluoroethane is subject to use restrictions. 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. R-134a is due to be banned from use in the European Union, starting with cars in 2011 and due to be banned completely by 2030. By model year 2021, newly manufactured light-duty vehicles in the United States will no longer use R-134a.
California may also prohibit the sale of canned R-134a to individuals to avoid non-professional recharge of air conditioners. 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. 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  nor is HFC-134a included in the § 7671a listing of class I and class II substances.
Production and reactions
- CHCl=CCl2 + 4 HF → CF3CH2F + 3 HCl
It reacts with butyllithium to give trifluorovinyl lithium:
- CF3CH2F + 2 BuLi → CF2=CFLi + LiF + 2 BuH
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. 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, however the decomposition temperature has been reported as above 370 °C,. 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. 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. It is considered safe for this use. In combination with pentafluoropropane, it is used as a topical vapocoolant spray for numbing boils before curettage. It has also been studied as a potential inhalational anesthetic, but it is nonanaesthetic at doses used in inhalers.
- List of refrigerants
- 1,1,1,2-Tetrafluoroethane (data page)
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- Chapter ATCP 136. MOBILE AIR CONDITIONERS; RECLAIMING OR RECYCLING REFRIGERANT. State.wi.us. (PDF). Retrieved 21 August 2011.
- Class I Ozone-depleting Substances. EPA.gov. Retrieved 21 August 2011.
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This propellant has been shown to be safe and nonanaesthetic in standard inhaler doses
- 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.
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- "Norflurane". DrugBank.
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|Wikimedia Commons has media related to Tetrafluoroethane.|
- International Chemical Safety Card 1281
- European Fluorocarbons Technical Committee (EFCTC)
- MSDS at Oxford University
- Concise International Chemical Assessment Document 11, at inchem.org
- Pressure temperature calculator
- "The Coexisting Curve of the Refrigerant HFC 134a: Some Scaling Models" (PDF). Archived from the original (PDF) on 29 September 2006. Retrieved 11 September 2007.
- R134a 2 phase computer cooling