1,1,1,2-Tetrafluoroethane
Encyclopedia
1,1,1,2-Tetrafluoroethane, R-134a, Genetron 134a, Suva 134a or HFC-134a, is a haloalkane
refrigerant
with thermodynamic properties similar to R-12
(dichlorodifluoromethane), but with less ozone depletion potential
. It has the formula CH2FCF3, and a boiling point
of −26.3 °C (−15.34 °F) at atmospheric pressure.
, and retrofit kits are available to convert units that were originally R-12
-equipped. Other uses include plastic foam blowing, as a cleaning solvent, a propellant for the delivery of pharmaceuticals (e.g. bronchodilator
s), wine cork removers, gas dusters, 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 also commonly used as a propellant for airsoft
airguns.
Recently, 1,1,1,2-tetrafluoroethane has been subject to use restrictions due to its contribution to climate change
. In the EU, it will be banned as of 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 also 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 October 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.
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 detector
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
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.
as a replacement for dichlorodifluoromethane
(R-12), which has 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 and 2004. It has insignificant ozone depletion potential (ozone layer
), significant global warming
potential (100-yr GWP
= 1430) and negligible acidification potential (acid rain
).
and the emission of toxic
gases including hydrogen fluoride
and carbonyl halides
. 1,1,1,2-Tetrafluoroethane itself has an LD50
(lethal concentration for 50% of subjects) in rats of 1,500 g/m³, making it relatively non-toxic, apart from the dangers inherent to 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. This can result in frostbite
when it contacts skin, as well as blindness
upon eye contact.
Haloalkane
The 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...
refrigerant
Refrigerant
A refrigerant is a substance used in a heat cycle usually including, for enhanced efficiency, a reversible phase change from a liquid to a gas. Traditionally, fluorocarbons, especially chlorofluorocarbons, were used as refrigerants, but they are being phased out because of their ozone depletion...
with thermodynamic properties similar to R-12
Dichlorodifluoromethane
Dichlorodifluoromethane , is a colorless gas, and 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...
(dichlorodifluoromethane), but with less ozone depletion potential
Ozone depletion potential
The 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 0.055...
. It has the formula CH2FCF3, and a boiling point
Boiling point
The 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) at atmospheric pressure.
Uses
1,1,1,2-Tetrafluoroethane is an inert 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-12Dichlorodifluoromethane
Dichlorodifluoromethane , is a colorless gas, and 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...
, and retrofit kits are available to convert units that were originally R-12
Dichlorodifluoromethane
Dichlorodifluoromethane , is a colorless gas, and 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...
-equipped. Other uses include plastic foam blowing, as a cleaning solvent, a propellant for the delivery of pharmaceuticals (e.g. bronchodilator
Bronchodilator
A bronchodilator is a substance that dilates the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the lungs. Bronchodilators may be endogenous , or they may be medications administered for the treatment of breathing difficulties...
s), wine cork removers, gas dusters, and in air driers for removing the moisture from compressed air
Compressed air
Compressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe, 10 percent of all electricity used by industry is used to produce compressed air, amounting to 80 terawatt hours consumption per year....
. 1,1,1,2-Tetrafluoroethane has also been used to cool computers in some overclocking
Overclocking
Overclocking is the process of operating a computer component at a higher clock rate than it was designed for or was specified by the manufacturer, but some manufacturers purposely underclock their components to improve battery life. Many people just overclock or 'rightclock' their hardware to...
attempts. It is also commonly used as a propellant for airsoft
Airsoft
Airsoft is a sport in which participants shoot round non-metallic pellets launched via replica firearms.Gameplay varies in style and composition but often range from short-term skirmishes, organized scenarios, military simulations, historical reenactments, to competition target shooting events...
airguns.
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
. In the EU, it will be banned as of 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 also 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 October 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.
1,1,1,2-tetrafluoroethane is also being considered as an organic solvent suitable for extraction of flavor
Flavor
Flavor or flavour is the sensory impression of a food or other substance, and is determined mainly by the chemical senses of taste and smell. The "trigeminal senses", which detect chemical irritants in the mouth and throat as well as temperature and texture, are also very important to the overall...
and fragrance compounds, as a possible alternative to other organic solvents and supercritical carbon dioxide
Supercritical carbon dioxide
Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.Carbon dioxide usually behaves as a gas in air at STP or as a solid called dry ice when frozen...
.
It can also be used as a solvent in organic chemistry, both in liquid and supercritical fluid
Supercritical fluid
A supercritical fluid is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist. It can effuse through solids like a gas, and dissolve materials like a liquid...
.
It is used in the resistive plate chamber particle detector
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 high-energy particles, such as those produced by nuclear decay, cosmic radiation, or reactions in a...
s in the Large Hadron Collider
Large Hadron Collider
The Large Hadron Collider is the world's largest and highest-energy particle accelerator. It is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature....
. 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
Sulfur hexafluoride is an inorganic, colorless, odorless, and non-flammable greenhouse gas. has an octahedral geometry, consisting of six fluorine atoms attached to a central sulfur atom. It is a hypervalent molecule. Typical for a nonpolar gas, it is poorly soluble in water but soluble in...
in magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
smelting
Smelting
Smelting is a form of extractive metallurgy; its main use is to produce a metal from its ore. This includes iron extraction from iron ore, and copper extraction and other base metals from their ores...
as a shielding gas
Shielding gas
Shielding gases are inert or semi-inert gases that are commonly used in several welding processes, most notably gas metal arc welding and gas tungsten arc welding . Their purpose is to protect the weld area from atmospheric gases, such as oxygen, nitrogen, carbon dioxide, and water vapour...
.
1,1,1,2-tetrafluoroethane is also being considered as an alternative to sulfur hexafluoride
Sulfur hexafluoride
Sulfur hexafluoride is an inorganic, colorless, odorless, and non-flammable greenhouse gas. has an octahedral geometry, consisting of six fluorine atoms attached to a central sulfur atom. It is a hypervalent molecule. Typical for a nonpolar gas, it is poorly soluble in water but soluble in...
as a dielectric gas
Dielectric gas
A dielectric gas, or insulating gas, is a dielectric material in gaseous state. Its main purpose is to prevent or rapidly quench electric discharges. Dielectric gases are used as electrical insulators in high voltage applications, e.g...
. Its arc-quenching properties are poor, but its dielectric properties are fairly good.
History
1,1,1,2-Tetrafluoroethane first appeared in the early 1990s1990s
File:1990s decade montage.png|From left, clockwise: The Hubble Space Telescope floats in space after it was taken up in 1990; American F-16s and F-15s fly over burning oil fields and the USA Lexie in Operation Desert Storm, also known as the 1991 Gulf War; The signing of the Oslo Accords on...
as a replacement for dichlorodifluoromethane
Dichlorodifluoromethane
Dichlorodifluoromethane , is a colorless gas, and 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...
(R-12), which has 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 and 2004. It has insignificant ozone depletion potential (ozone layer
Ozone layer
The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone . This layer absorbs 97–99% of the Sun's high frequency ultraviolet light, which is potentially damaging to the life forms on Earth...
), significant global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
potential (100-yr GWP
Global warming potential
Global-warming potential is a relative measure of how much heat a greenhouse gas traps in the atmosphere. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide. A GWP is calculated over a specific time...
= 1430) and negligible acidification potential (acid rain
Acid rain
Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions . It can have harmful effects on plants, aquatic animals, and infrastructure. Acid rain is caused by emissions of carbon dioxide, sulfur dioxide and nitrogen...
).
Safety
Contact of 1,1,1,2-tetrafluoroethane with flames or hot surfaces in excess of 250 °C (482 °F) may cause vapor decompositionDecomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
and the emission of toxic
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
gases including hydrogen fluoride
Hydrogen fluoride
Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas 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...
and carbonyl halides
Carbonyl fluoride
Carbonyl fluoride is the chemical compound with the formula COF2. This gas, like its analog phosgene, is highly toxic. The molecule is planar with C2v symmetry.-Safety:...
. 1,1,1,2-Tetrafluoroethane itself has an LD50
Lethal dose
A 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...
(lethal concentration for 50% of subjects) in rats of 1,500 g/m³, making it relatively non-toxic, apart from the dangers inherent to 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
Thermal energy
Thermal energy is the part of the total internal energy of a thermodynamic system or sample of matter that results in the system's temperature....
. As a result, it will greatly lower the temperature of any object it contacts as it evaporates. This can result in frostbite
Frostbite
Frostbite is the medical condition where localized damage is caused to skin and other tissues due to extreme cold. Frostbite is most likely to happen in body parts farthest from the heart and those with large exposed areas...
when it contacts skin, as well as blindness
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
upon eye contact.
See also
- list of refrigerants
- DichlorodifluoromethaneDichlorodifluoromethaneDichlorodifluoromethane , is a colorless gas, and 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...
- 1,1,1,2-Tetrafluoroethane (data page)1,1,1,2-Tetrafluoroethane (data page)This page lists chemical and physical properties of 1,1,1,2-tetrafluoroethane.Vapor Pressure at 25 °C kPa 666.1bar 6.661psia 96.61Heat of Vaporization at Boiling Point kJ/kg 217.2Btu/lb 93.4...
- TetrabromoethaneTetrabromoethaneTetrabromoethane is a halogenated hydrocarbon, chemical formula C2H2Br4. Although three bromine atoms may bind to one of the carbon atoms creating 1,1,1,2-tetrabromoethane this is not thermodynamically favorable, so in practice tetrabromoethane is equal to 1,1,2,2-tetrabromoethane, where each...
- TetrachloroethaneTetrachloroethaneTetrachloroethane may refer to either of two isomeric chemical compounds:* 1,1,1,2-Tetrachloroethane * 1,1,2,2-Tetrachloroethane -See also:* Tetrachloroethene* Trichloroethane *Tetrafluoroethane*Tetrabromoethane...
External links
- Information about HFCs, 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
- R134a 2 phase computer cooling