1,1,1,2-TETRAFLUOROETHANE

1,1,1,2-Tetrafluoroethane
Structure 3-D structure
General
Systematic name	1,1,1,2-tetrafluoroethane
Other names	Genetron 134a HFC-134a R-134a Freon 134a
Molecular formula	C2H2F4
SMILES	FC(F)(F)C(F)
Molar mass	102.03 g/mol
Appearance	Colorless gas.
CAS number
Properties
Density and phase	0.00425 g/cm³, gas.
Solubility in water	Insoluble.
Melting point	-103.3°C (169.85 K)
Boiling point	-26.08°C (247.07 K)
Structure
Molecular shape	Planar.
Dipole moment	? D
Hazards
MSDS	External MSDS
Main hazards	Asphyxiant.
NFPA 704
Flash point	Non-flammable.
R/S statement	R: ? S: , , , .
RTECS number	KI8842500
Supplementary data page
Structure and properties	''n'', εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Other anions	?
Other cations	?
Related refrigerants	Difluoromethane Pentafluoroethane
Related compounds	1,1,2,2,2-pentafluoroethane 2-Chloro- 1,1,1,2-tetrafluoroethane 1,1,1-Trichloroethane
Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa)

'1,1,1,2-Tetrafluoroethane', also called simply 'tetrafluoroethane', 'R-134a', 'Genetron 134a', Freon 134a or 'HFC-134a', is a haloalkane refrigerant without an ozone depletion potential and thermodynamic properties similar to R-12 (dichlorodifluoromethane). It has the formula CH₂FCF₃, and a boiling point of −26.6 °C (−15.9 °F).

Contents

Uses

History

Safety

References

External links

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. bronchodilators), gas dusters, and in air driers, that is, for removing the moisture from compressed air. Moisture present in compressed air has a harmful effect on pneumatic systems. Tetrafluoroethane has also been used to cool computers in some overclocking attempts. It is also commonly used as a power source for airsoft airguns.

Recently, R-134a has been subject to use restrictions due to its theorized contribution to climate change. In the EU, it will be banned as from 2011 in all new cars ^[1], and California may prohibit the sale of canned HFC-134a to individuals to avoid non-professional recharge of the air conditioner. ^[2]

History

R-134a first appeared in the early 1990s as a replacement for Dichlorodifluoromethane (R-12), which has significant ozone depleting properties. ^[3] R-134a 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 atmosphere, with a recent study revealing a doubling in atmospheric concentration between 2001-2004.^[4] It has insignificant ozone depletion potential (ozone layer), significant global warming potential (GWP₁₀₀ = 1300) and negligible acidification potential (acid rain). 1,1,1,2-Tetrafluoroethane is slowly converted to trifluoroacetic acid through a radical reaction in the upper atmosphere and leads to a detectable amount of several ng/L in acid rain. ^[5]

Safety

Contact of 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 halides.^[6] Tetrafluoroethane itself has an LC₅₀ (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.^[7][8]
Aerosol cans containing tetrafluoroethane, when inverted, become effective freeze sprays. Under pressure, 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 contacting skin.

References

1. European Directive 2006/40/EC relating to emissions from air-conditioning systems in motor vehicles
2. Early Action Measure California: Use ban of canned HFC-134a
3. The Atmospheric Degradation and Impact of 1,1,1,2-Tetrafluorethane (Hydrofluorocarbon 134a), Franklin J, , , Chemosphere, 1993
4. Greenhouse gas monitoring at the Zeppelin station - Annual report 2004 (TA-2110/2005)
5. Natural Background Levels of Trifluoroacetate in Rain and Snow, von Sydow L, Grimvall AB, Borén HB, Laniewski K, Nielsen AT, , , Enviro Sci Technol, 2000
6. MSDS # GTRN-0047 For Genetron® 134aUV, Honeywell International, , , ,
7. An overview of the toxicology of HFA-134a (1,1,1,2-tetrafluoroethane), Alexander D. J, Libretto S. E., , , Hum. Exp. Toxicol., 1995
8. Kinetic analysis of the shock wave decomposition of 1,1,1,2-tetrafluoroethane, G. E. Millward, E. Tschuikow-Roux, , , , 1972

External links

★

★ Honeywell Refrigerant Data and MSDSs

★ MSDS at Oxford University

★ Concise International Chemical Assessment Document 11 at inchem.org

★ Quick Change R-134A MSDS

★ Pressure temperature calculator