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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). It has the formula CFCHF and a
boiling point The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding envi ...
of −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are colored
light blue Light blue is a color or range of colors, typically a lightened shade with a hue between cyan and blue. The first use of "light blue" as a color term in English language, English is in the year 1915. In Russian and some other languages, there ...
. A phaseout and transition to HFO-1234yf and other refrigerants, with GWPs similar to CO2, began in 2012 within the automotive market.


Uses

1,1,1,2-Tetrafluoroethane is a non-flammable gas used primarily as a "high-temperature" refrigerant for domestic
refrigeration Refrigeration is any of various types of cooling of a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is ejected to a place of higher temperature).IIR International Dictionary of ...
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., inhaler canisters such as for bronchodilators), wine cork removers, gas dusters ("canned air"), and in air driers for removing the moisture from
compressed air Compressed air is air kept under a pressure that is greater than atmospheric pressure. Compressed air in vehicle tires and shock absorbers are commonly used for improved traction and reduced vibration. Compressed air is an important medium for t ...
. 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, both as a liquid and a supercritical fluid. It is used in the
resistive plate chamber A Resistive plate chamber (RPC) is a particle detector widely used in high energy physics. They are used for detecting muons in most of the modern experiments including ATLAS experiment, ATLAS, Compact Muon Solenoid, CMS, and BES III. References
particle detector In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing elementary particle, particles, such as t ...
s 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 Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
smelting Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron-making, iron, copper extraction, copper ...
as a shielding gas.


History and environmental impacts

1,1,1,2-Tetrafluoroethane was introduced in the early 1990s as a replacement for dichlorodifluoromethane (R-12), which has massive ozone depleting properties. Even though 1,1,1,2-Tetrafluoroethane has insignificant ozone depletion potential ( ozone layer) and negligible acidification potential (
acid rain Acid rain is rain or any other form of Precipitation (meteorology), precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists b ...
), it has a 100-year global warming potential (GWP) 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. Thus it was included in the IPCC list of greenhouse gases. R-134a began being phased out from use in the
European Union The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are Geography of the European Union, located primarily in Europe. The u ...
, starting in the mid 2010s, by a directive of 2006, recommending the replacement of gases in air conditioning systems with a GWP above 100. 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 (CFCF=CH) in automobile air-conditioning systems. As of model year 2021, newly manufactured light-duty vehicles in the United States 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 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.Chapter ATCP 136. MOBILE AIR CONDITIONERS; RECLAIMING OR RECYCLING REFRIGERANT
State.wi.us. (PDF). Retrieved 21 August 2011.
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

Tetrafluoroethane is typically made by reacting trichloroethylene with hydrogen fluoride: :CHCl=CCl + 4 HF → CFCHF + 3 HCl It reacts with butyllithium to give trifluorovinyl lithium: :CFCHF + 2 BuLi → CF=CFLi + LiF + 2 BuH


Safety

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 of 1,500 g/m in rats, making it relatively non-toxic, apart from the dangers inherent to inhalant abuse. Its gaseous form 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 The term "thermal energy" is often used ambiguously in physics and engineering. It can denote several different physical concepts, including: * Internal energy: The energy contained within a body of matter or radiation, excluding the potential en ...
. As a result, it will greatly lower the temperature of any object it contacts as it evaporates.


Medical use

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 An inhalational anesthetic is a chemical compound possessing general anesthetic properties that is delivered via inhalation. They are administered through a face mask, laryngeal mask airway or tracheal tube connected to an anesthetic vaporiser ...
, but it is nonanaesthetic at doses used in inhalers.


See also

*
List of refrigerants This is a list of refrigerants, sorted by their ASHRAE-designated numbers, commonly known as R numbers. Many modern refrigerants are human-made halogenated gases, especially fluorinated gases and chlorinated gases, that are frequently referred ...
* Tetrabromoethane * Tetrachloroethane


References


External links

*
European Fluorocarbons Technical Committee (EFCTC)




at inchem.org

*
R134a 2 phase computer cooling
{{DEFAULTSORT:Tetrafluoroethane, 1, 1, 1, 2- Fluoroalkanes Refrigerants Automotive chemicals Propellants Airsoft Excipients Greenhouse gases GABAA receptor positive allosteric modulators General anesthetics Hydrofluorocarbons