1,1-Difluoroethane, or DFE, is an organofluorine compound with the chemical formula C2H4F2. This colorless gas is used as a refrigerant, where it is often listed as R-152a (refrigerant-152a) or HFC-152a (hydrofluorocarbon-152a). It is also used as a propellant for aerosol sprays and in gas duster products. As an alternative to chlorofluorocarbons, it has an ozone depletion potential of zero, a lower global warming potential (124) and a shorter atmospheric lifetime (1.4 years). It has recently been approved for use in automobile applications as an alternative to R-134a.
|Preferred IUPAC name
3D model (JSmol)
|Molar mass||66.05 g/mol|
|Density||900 g/L @ 25 °C|
|Melting point||−117 °C (−179 °F; 156 K)|
|Boiling point||−25 °C (−13 °F; 248 K)|
|0.54% @ 0 °C|
|Vapor pressure||4020 mmHg/536 kPa @ 21.1 °C
5.1 bar/510 kPa @ 20 °C
|Viscosity||0.00887 cP (8.87 µPa·s) @ 25 °C|
|Safety data sheet||SDS for 1,1-difluoroethane|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
- HCCH + 2 HF → CH3CHF2
This molecule, thanks to its relatively low Global Warming Potential (GWP) index equal to 140 and to favorable thermophysical properties, has been proposed as a very promising environmentally friendly alternative to R134a. Despite its flammability, it also presents operating pressures and Volumetric Cooling Capacity (VCC) similar to R134a so it can be used in large chillers  or in more particular applications like heat pipe finned heat exchangers.
The molecular weight of difluoroethane is 66, making it a useful and convenient tool for detecting vacuum leaks in GC-MS systems. The cheap and freely available gas has a molecular weight and fragmentation pattern (base peak 51 m/z in typical EI-MS, major peak at 65 m/z) distinct from anything in air. If mass peaks corresponding to 1,1-difluoroethane are observed immediately after spraying a suspect leak point, leaks may be identified.
Difluoroethane is an intoxicant if inhaled and is highly addictive. The low cost, easy availability, and packaging of dusting sprays in a valved aerosol can encourage impulsive use. The practice of deliberately inhaling or “huffing” tinned wind can be fatal. Though often overlooked due to lack of identification via common drug screens, it has caused the instantaneous deaths of numerous individuals by precipitating fatal cardiac arrhythmia. Several reports of fatal car crashes have been linked to drivers huffing 1,1-difluoroethane. Because of inhalant abuse, a bitterant is added to some brands of consumer tinned wind products, however even this measure is not legally required and has not prevented widespread use of this product as a drug.
In a DuPont study, rats were exposed to up to 25,000 ppm (67,485 mg m−3) for six hours daily, five days a week for two years. This has become the no-observed-adverse-effect level for this substance. Prolonged exposure to 1,1-difluoroethane has been linked in humans to the development of coronary disease and angina.
Though not extremely flammable in gaseous form, 1,1-difluoroethane can burn under some conditions. As such, there is also a warning label present on some gas dusters. When inverted to spray liquid, the boiling fluorocarbon aerosol is easily ignitable, producing a very large blast of flame and extremely toxic gases such as hydrogen fluoride and carbonyl fluoride as combustion products.
- 1,1-Difluoroethane at Sigma-Aldrich
- "Changes in Atmospheric Constituents and in Radiative Forcing" (PDF). Cambridge University Press. 2007. p. 212. Retrieved 11 May 2017. dead link 18 February 2019
- "Global Warming Potentials of ODS Substitutes". U.S. Environmental Protection Agency. 2010. Archived from the original on 16 October 2010. Retrieved 20 September 2010.
- Siegemund, Günter; Schwertfeger, Werner; Feiring, Andrew; Smart, Bruce; Behr, Fred; Vogel, Herward; McKusick, Blaine (2010). "Fluorine Compounds, Organic". In Bohnet, Matthias; Bellussi, Giuseppe; Bus, James; et al. Ullmann's Encyclopedia of Industrial Chemistry. John Wiley & Sons. doi:10.1002/14356007.a11_349.
- Avella J, Wilson JC, Lehrer M (March 2006). "Fatal cardiac arrhythmia after repeated exposure to 1,1-difluoroethane (DFE)". The American Journal of Forensic Medicine and Pathology. 27 (1): 58–60. doi:10.1097/01.paf.0000202715.71009.0e. PMID 16501351.
- Broussard LA, Brustowicz T, Pittman T, Atkins KD, Presley L (November 1997). "Two traffic fatalities related to the use of difluoroethane". Journal of Forensic Sciences. 42 (6): 1186–7. PMID 9397568.
- Hahn, T; Avella, J; Lehrer, M (2006). "A motor vehicle accident fatality involving the inhalation of 1,1-difluoroethane". Journal of Analytical Toxicology. 30 (8): 638–42. doi:10.1093/jat/30.8.638. PMID 17132266.
- "Autopsy: man in crash died from inhaling computer cleaner". The Times News. 10 March 2012. Archived from the original on 12 March 2012.
- "1,1-Difluoroethane". National Library of Medicine HSDB Database. 1994. Retrieved 8 June 2010.