1,1,1,2-Tetrafluoroethane
- Tetrafluoroethane ( not unique )
- R134a
- Hydrofluorocarbon 134A (INCI)
Colorless gas
Gaseous
1.21 g · cm -3 ( 25 ° C)
-101 ° C
-26 ° C
8200 hPa ( 32 ° C)
Attention
1000 ml · m-3
1,430 (relative to 100 years)
Template: Infobox chemical / molecular formula search available
( Often referred to as short, but imprecise tetrafluoroethane, trade name R134a), 1,1,1,2 -tetrafluoroethane is a hydrofluorocarbon ( a hydrofluoroalkane ), which is used as a propellant and refrigerant, as well as an alternative to chlorofluorocarbons hydrocarbons.
Besides 1,1,1,2- tetrafluoroethane, there is the isomer 1,1,2,2- tetrafluoroethane, which is also referred to as tetrafluoroethane.
Technical production
See fluorocarbons.
Properties
Tetrafluoroethane is a colorless and almost odorless gas, which can be easily liquefied by pressure. The critical point is at 101.15 ° C and 41 bar. The degradation in the environment caused by photo-oxidation, the very persistent trifluoroacetic acid ( TFA).
Tetrafluoroethane However, in contrast to CFC no destructive effect on the ozone layer, is a potent greenhouse gas. Its greenhouse effect is the 1430 times the same amount of carbon dioxide based on a time horizon of 100 years (see global warming potential ).
Application
Because of its favorable properties found tetrafluoroethane application in refrigerating machines such as refrigerators, and in the operation of steam turbines in the Organic Rankine Cycle without steam as the working fluid.
All today's popular car air conditioning systems based on R134a as refrigerant. This, however since 2011 may no longer be used for air conditioning systems in new cars in the EU. Another use of it as a test / test equipment for optical smoke detectors. Also in compressor coolers and coolers as well as a main ingredient in cold spray from the electronics, it is utilized.
Tetrafluoroethane is also used for the protective cover of magnesium melts. This is generally a gas mixture with nitrogen. The mixing ratio is approximately 99.5-99.8 % nitrogen and 0.5 to 0.2 % tetrafluoroethane, depending on the application. In conjunction with humidity tetrafluoroethane formed in the heat hydrofluoric acid, which leads to increased corrosion of steel.
In medicine it is used as a propellant for metered-dose inhalers, for example, a number of drugs with agents such as salbutamol or fluticasone.
Future
Since 2011, an EU directive prohibits the use of HFCs with a global warming potential greater than 150 ( this includes R134a) in air conditioning systems of cars with new type approval. From 2017 to no more new vehicles may be sold with such refrigerants. Instead, are to be used have little or no effective climate refrigerants such as carbon dioxide (R744 ), ammonia, propane, or 2,3,3,3 - Tetrafluoropropene in the future.