1,1,1,2-Tetrafluoroethane

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1,1,1,2-Tetrafluoroethane
Image:1,1,1,2-Tetrafluoroethane.png Image:1,1,1,2-Tetrafluoroethane.gif
General
Systematic name	1,1,1,2-tetrafluoroethane
Other names	Suva 134a HFC-134a R-134a
Molecular formula	C₂H₂F₄
SMILES	FC(F)(F)C(F)
Molar mass	102.03 g/mol
Appearance	Colorless gas.
CAS number	[811-97-2] [1]
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	Image:NFPA 704.svg 1 1 1
Flash point	Non-flammable.
R/S statement	R: ? S: S2, S23, S24/25, S51.
RTECS number	KI8842500
Supplementary data page
Structure and properties	n, ε_r, 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) Infobox disclaimer and references

1,1,1,2-Tetrafluoroethane, also called simply tetrafluoroethane, R-134a or HFC-134a, is a 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).

1 Uses
2 History
3 Safety
4 References
5 External links

[edit] 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 solvents and as a propellant for the delivery of pharmaceuticals (e.g. bronchodilators), canned air, and in air driers, i.e., 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.

Image:Tetrafluoroethane liquid.jpg

[edit] History

R-134a first appeared in the early 1990s as a replacement for Dichlorodifluoromethane (R-12), which has significant ozone depleting properties. <ref>Franklin J (1993). "The Atmospheric Degradation and Impact of 1,1,1,2-Tetrafluorethane (Hydrofluorocarbon 134a)". Chemosphere 27: 1565-1601. DOI:10.1016/0045-6535(93)90251-Y.</ref> 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, has insignificant ozone depletion potential (ozone layer), significant global warming potential 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 rain. <ref>von Sydow L, Grimvall AB, Borén HB, Laniewski K, Nielsen AT (2000). "Natural Background Levels of Trifluoroacetate in Rain and Snow". Enviro Sci Technol 34: 3115-3118. DOI:10.1021/es9913683.</ref>

[edit] Safety

Contact of tetrafluoroethane with flames or hot surfaces (in excess of around 120 °F or 50 °C) may cause vapor decomposition and the emission of toxic gases. 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. <ref> Alexander D. J, Libretto S. E. (1995). "An overview of the toxicology of HFA-134a (1,1,1,2-tetrafluoroethane)". Hum. Exp. Toxicol. 14: 715-20.</ref> <ref> G. E. Millward, E. Tschuikow-Roux (1972). "Kinetic analysis of the shock wave decomposition of 1,1,1,2-tetrafluoroethane" 76 (3): 292 - 298. DOI:10.1021/j100647a002.</ref>

Aerosol cans containing tetrafluoroethane, when turned upside-down, 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 with which it comes into contact as it evaporates. This can result in frostbite if it comes into contact with skin.

According to the MSDS, "In a two-year inhalation study, HFC-134a at a concentration of 50,000 ppm, produced an increase in late-occurring benign testicular tumors, testicular hyperplasia and testicular weight."