1,1,1,2-Tetrafluoroethane,
R-134a,
Genetron 134a,
Suva 134a or
HFC-134a, is a
haloalkaneThe haloalkanes are a group of chemical compounds, derived from alkanes containing one or more halogens. They are a subset of the general class of halocarbons although the distinction is not often made. Haloalkanes are widely used commercially and consequently are known under many chemical and...
refrigerantA refrigerant is a compound used in a heat cycle that reversibly undergoes a phase change from a gas to a liquid. Traditionally, fluorocarbons, especially chlorofluorocarbons are the traditional refrigerants, but they are being phased out because of their ozone depletion effects...
with thermodynamic properties similar to
R-12Dichlorodifluoromethane , usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane , used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture was banned in the United States along with many other countries in 1994 due to...
(dichlorodifluoromethane), but without its
ozone depletion potentialThe ozone depletion potential of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane being fixed at an ODP of 1.0. Chlorodifluoromethane , for example, has an ODP of 0.05.The first proposal of ODP came from Wuebbles in 1983...
. It has the formula CH
2FCF
3, and a
boiling pointThe boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
of −26.3 °C (−15.34 °F).
1,1,1,2-Tetrafluoroethane is an inert gas used primarily as a "high-temperature" refrigerant for domestic refrigeration and automobile air conditioners.
1,1,1,2-Tetrafluoroethane,
R-134a,
Genetron 134a,
Suva 134a or
HFC-134a, is a
haloalkaneThe haloalkanes are a group of chemical compounds, derived from alkanes containing one or more halogens. They are a subset of the general class of halocarbons although the distinction is not often made. Haloalkanes are widely used commercially and consequently are known under many chemical and...
refrigerantA refrigerant is a compound used in a heat cycle that reversibly undergoes a phase change from a gas to a liquid. Traditionally, fluorocarbons, especially chlorofluorocarbons are the traditional refrigerants, but they are being phased out because of their ozone depletion effects...
with thermodynamic properties similar to
R-12Dichlorodifluoromethane , usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane , used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture was banned in the United States along with many other countries in 1994 due to...
(dichlorodifluoromethane), but without its
ozone depletion potentialThe ozone depletion potential of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane being fixed at an ODP of 1.0. Chlorodifluoromethane , for example, has an ODP of 0.05.The first proposal of ODP came from Wuebbles in 1983...
. It has the formula CH
2FCF
3, and a
boiling pointThe boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
of −26.3 °C (−15.34 °F).
Uses
1,1,1,2-Tetrafluoroethane is an inert gas used primarily as a "high-temperature" refrigerant for domestic refrigeration and automobile air conditioners. Other uses include plastic foam blowing, as a cleaning solvent and as a propellant for the delivery of pharmaceuticals (e.g.
bronchodilatorA bronchodilator is a substance that dilates the bronchi and bronchioles, decreasing airway resistance and thereby facilitating airflow. Bronchodilators may be endogenous , or they may be medications administered for the treatment of breathing difficulties...
s), gas dusters, and in air driers, for removing the moisture from
compressed airCompressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe 10 % of all electricity used by industry is used to produce compressed air...
. Moisture present in compressed air has a harmful effect on pneumatic systems. 1,1,1,2-Tetrafluoroethane has also been used to cool computers in some
overclockingOverclocking is the process of running a computer component at a higher clock rate than it was designed for or was specified by the manufacturer, usually practiced by enthusiasts seeking an increase in the performance of their computers...
attempts. It is also commonly used as a propellant for
airsoftAirsoft is a sport, in which participants organize meetings at dedicated airsoft battlefields often adapted to provide walls, bunkers, trenches, buildings, towers, and other similar man-made field enhancements to simulate real combat environments....
airguns.
Recently, 1,1,1,2-tetrafluoroethane has been subject to use restrictions due to its contribution to
climate changeClimate change is a change in the statistical distribution of weather over periods of time that range from decades to millions of years. It can be a change in the average weather or a change in the distribution of weather events around an average...
. In the EU, it will be banned as from 2011 in all new cars. The Society of Automotive Engineers (SAE) has proposed 1,1,1,2-tetrafluoroethane (HFC-134a) to be best replaced by a new fluorochemical refrigerant HFO-1234yf (CF3CF=CH2) in automobile air-conditioning systems. California may prohibit the sale of canned 1,1,1,2-tetrafluoroethane to individuals to avoid non-professional recharge of air conditioners. A ban has been in place in Wisconsin since Oct 1994 under ATCP 136 prohibiting sales of container sizes holding less than 15 lbs of 1,1,1,2-tetrafluoroethane, but this restriction applies only when the chemical is intended to be a refrigerant. It appears, for example, that it is 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. The chemical has also been banned in mobile air conditioners in the state of California.
History
1,1,1,2-Tetrafluoroethane first appeared in the early
1990sThe 1990s was the decade that ran from January 1, 1990, to December 31, 1999, the last decade of the 20th century. It was the first decade following the effective end of the Cold War...
as a replacement for
dichlorodifluoromethaneDichlorodifluoromethane , usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane , used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture was banned in the United States along with many other countries in 1994 due to...
(R-12), which has supposed ozone depleting properties. 1,1,1,2-Tetrafluoroethane has been atmospherically modeled for its impact on depleting ozone and as a contributor to global warming. Research suggests that over the past 10 years the concentration of 1,1,1,2-tetrafluoroethane has increased significantly in the Earth's atmosphere, with a recent study revealing a doubling in atmospheric concentration between 2001–2004. It has insignificant ozone depletion potential (
ozone layerThe ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone . This layer absorbs 93-99% of the sun's high frequency ultraviolet light, which is potentially damaging to life on earth. Over 91% of the ozone in Earth's atmosphere is present here...
), significant
global warmingGlobal warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C during the last century...
potential (
GWPGlobal warming potential is a measure of how much a given mass of greenhouse gas is estimated to contribute to global warming. It is a relative scale which compares the gas in question to that of the same mass of carbon dioxide...
= 1300) and negligible acidification potential (
acid rainAcid rain is rain or any other form of precipitation that is unusually acidic, i.e. elevated levels of hydrogen ions . It has harmful effects on plants, aquatic animals, and infrastructure. Acid rain is mostly caused by emissions of compounds of sulfur, nitrogen, and carbon which react with the...
). 1,1,1,2-Tetrafluoroethane is slowly converted to
trifluoroacetic acidTrifluoroacetic acid is the simplest perfluorinated carboxylic acid chemical compound with the formula CF3CO2H. It is a strong carboxylic acid due to the influence of the electronegative trifluoromethyl group. TFA is almost 100,000-fold more acidic than acetic acid...
through a
radicalIn chemistry, radicals are atoms, molecules, or ions with unpaired electrons on an otherwise open shell configuration. These unpaired electrons are usually highly reactive, so radicals are likely to take part in chemical reactions...
reactionA chemical reaction is a process that leads to the transformation of one set of chemical substances to another. They are studied by chemists under a field of science called chemistry. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, often coming about...
in the upper
atmosphereAn atmosphere is a layer of gases that may surround a material body of sufficient mass, by the gravity of the body, and are retained for a longer duration if gravity is high and the atmosphere's temperature is low...
and leads to a detectable amount of several ng/L in
acid rainAcid rain is rain or any other form of precipitation that is unusually acidic, i.e. elevated levels of hydrogen ions . It has harmful effects on plants, aquatic animals, and infrastructure. Acid rain is mostly caused by emissions of compounds of sulfur, nitrogen, and carbon which react with the...
in some models.
Safety
Contact of 1,1,1,2-tetrafluoroethane with flames or hot surfaces in excess of 250 °C (482 °F) may cause vapor
decompositionDecomposition is the process by which tissues of a dead organism break down into simpler forms of matter. The process is essential for new growth and development of living organisms because it recycles the finite matter that occupies physical space in the biome. Bodies of living organisms begin to...
and the emission of
toxicA toxin is a poisonous substance produced by living cells or organisms ....
gases including
hydrogen fluorideHydrogen fluoride is a chemical compound with the formula HF. It is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the petrochemical...
and
carbonyl halidesCarbonyl fluoride is the chemical compound with the formula COF2. This gas, like its analogue phosgene, is highly toxic. The molecule is planar with C2v symmetry.-Safety:...
. 1,1,1,2-Tetrafluoroethane itself has an
LC50A lethal dose is an indication of the lethality of a given substance or type of radiation. Because resistance varies from one individual to another, the 'lethal dose' represents a dose at which a given percentage of subjects will die.The most commonly-used lethality indicator is the...
(lethal concentration for 50% of subjects) in rats of 1,500 g/m³, making it relatively non-toxic. However, its gaseous form is denser than air, and will displace air in the lungs. This can result in asphyxiation if excessively inhaled.
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. This can result in
frostbiteFrostbite-is a condition that results in body tissues is frozen. the next step is hyporterma. is the medical condition wherein localized damage is caused to skin and other tissues due to extreme cold....
when it contacts skin.
External links