1,1,1,2-Tetrafluoroethane (also known as norflurane (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...

), R-134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, or HFC-134a) is a hydrofluorocarbon (HFC) and

haloalkane The haloalkanes (also known as halogenoalkanes or alkyl halides) are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely ...

refrigerant A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulate ...

with thermodynamic properties similar to R-12 (dichlorodifluoromethane) but with insignificant

ozone depletion potential The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane (R-11 or CFC-11) being fixed at an ODP of 1.0. Chlorodifluoromethane (R-22), for examp ...

and a lower 100-year

global warming potential Global warming potential (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (). GWP is 1 for . For other gases it depends on the gas and the time ...

(1,430, compared to R-12's GWP of 10,900). It has the formula CFCHF and a boiling point of −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are colored

light blue The first use of "light blue" as a color term in English is in the year 1915. In Russian and some other languages, there is no single word for blue, but rather different words for light blue (, goluboy) and dark blue (, siniy). The ancient Gre ...

. 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 The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...

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. Tetrafluoroethane liquid

Other common uses include plastic foam blowing, as a cleaning solvent, a propellant for the delivery of pharmaceuticals (e.g.

bronchodilator A bronchodilator or broncholytic (although the latter occasionally includes secretory inhibition as well) is a substance that dilates the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the l ...

s), 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 In computing, overclocking is the practice of increasing the clock rate of a computer to exceed that certified by the manufacturer. Commonly, operating voltage is also increased to maintain a component's operational stability at accelerated spe ...

attempts. It is the refrigerant used in plumbing pipe freeze kits. It is also commonly used as a propellant for

airsoft Airsoft is a team game in which participants eliminate opposing players by tagging them out of play with spherical plastic projectiles shot with mock air weapons(usually powered by an electronic motor) called airsoft guns. Although similar ...

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 A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for p ...

, both in liquid and

supercritical fluid A supercritical fluid (SCF) is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. It can effuse through porous s ...

. It is used in the resistive plate chamber

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 particles, such as those produced by ...

s in the

Large Hadron Collider The Large Hadron Collider (LHC) is the world's largest and highest-energy particle collider. It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and hundr ...

. 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 Sulfur hexafluoride or sulphur hexafluoride ( British spelling) is an inorganic compound with the formula SF6. It is a colorless, odorless, non- flammable, and non-toxic gas. has an octahedral geometry, consisting of six fluorine atoms attach ...

magnesium Magnesium is a chemical element with the 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 of the periodic ...

smelting Smelting is a process of applying heat to ore, to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a ...

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 The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in rel ...

) and negligible acidification potential ( acid rain), it has a 100-year

(GWP) of 1430 and an approximate atmospheric lifetime of 14 years. Its concentration in the atmosphere and contribution to

radiative forcing Radiative forcing (or climate forcing) is the change in energy flux in the atmosphere caused by natural or anthropogenic factors of climate change as measured by watts / metre2. It is a scientific concept used to quantify and compare the exter ...

have been growing since its introduction. Thus it was included in the

IPCC list of greenhouse gases This is a list of the most influential long-lived, well-mixed greenhouse gases, along with their tropospheric concentrations and direct radiative forcings, as identified by the Intergovernmental Panel on Climate Change (IPCC). Abundances of thes ...

R-134a was consequently banned from use in the European Union, starting with new cars in 2011, by a directive of 2006 banning 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. 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.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 The chemical compound trichloroethylene is a halocarbon commonly used as an industrial solvent. It is a clear, colourless non-flammable liquid with a chloroform-like sweet smell. It should not be confused with the similar 1,1,1-trichloroethane, ...

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 A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...

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 Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ...

and the emission of

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

gases including hydrogen fluoride and

carbonyl fluoride Carbonyl fluoride is a chemical compound with the formula COF2. It is a carbon oxohalide. This gas, like its analog phosgene, is colourless and highly toxic. The molecule is planar with ''C''2v symmetry, bond lengths of 1.174 Å (C=O) and 1.31 ...

, 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 is denser than air and will displace air in the lungs. This can result in

asphyxia Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects primarily the tissues and organs. There are many circumstances that ca ...

tion 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 used loosely in various contexts in physics and engineering. It can refer to several different well-defined physical concepts. These include the internal energy or enthalpy of a body of matter and radiation; heat, ...

. As a result, it will greatly lower the temperature of any object it contacts as it evaporates. Freon 134a refrigerant for car AC 001 (cropped)

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

boil A boil, also called a furuncle, is a deep folliculitis, which is an infection of the hair follicle. It is most commonly caused by infection by the bacterium ''Staphylococcus aureus'', resulting in a painful swollen area on the skin caused by an ...

s before curettage. It has also been studied as a potential inhalational anesthetic, but it is nonanaesthetic at doses used in inhalers.

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