1,1-Difluoroethane

1,1-Difluoroethane^[1]

Names
Preferred IUPAC name 1,1-Difluoroethane
Other names Difluoroethane Freon 152a Ethylidene difluoride Ethylidene fluoride HFC-152a R-152a DFE
Identifiers
CAS Number	75-37-6 Y
3D model (JSmol)	Interactive image
ChemSpider	6128 Y
ECHA InfoCard	100.000.788
PubChem CID	6368
RTECS number	KI1410000
UNII	0B1U8K2ME0 Y
InChI InChI=1S/C2H4F2/c1-2(3)4/h2H,1H3 Y Key: NPNPZTNLOVBDOC-UHFFFAOYSA-N Y InChI=1/C2H4F2/c1-2(3)4/h2H,1H3 Key: NPNPZTNLOVBDOC-UHFFFAOYAM
SMILES FC(F)C
Properties
Chemical formula	C2H4F2
Molar mass	66.05 g/mol
Density	2.7014 g/L @ 25 °C
Melting point	−117 °C (−179 °F; 156 K)
Boiling point	−25 °C (−13 °F; 248 K)
Solubility in water	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
Hazards
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).
Y verify (what is YN ?)
Infobox references

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).^[2][3] It has recently been approved for use in automobile applications as an alternative to R-134a.

Production

1,1-Difluoroethane is produced by the mercury-catalyzed addition of hydrogen fluoride to acetylene:^[4]

HCCH + 2 HF → CH₃CHF₂

The intermediate in this process is vinyl fluoride, the monomeric precursor to polyvinyl fluoride.

Uses

In addition to serving as a refrigerant, 1,1-difluoroethane is also commonly used in gas duster (commonly thought of as "canned air") and many consumer aerosol products, especially those subject to stringent VOC requirements.

The molecular weight of difluoroethane is 66, making it a useful and convenient tool for detecting vacuum leaks in GC-MS systems due to high availability the gas can be sprayed around common sources of leaks while manually observing the mass spectrum scan around mz 66 and looking for a peak to detect the source of the leak.

Safety

The practice of deliberately inhaling or “huffing” canned air can be fatal. It caused a fatal cardiac arrhythmia in a 42-year-old man.^[5] Several reports of fatal car crashes have been linked to drivers huffing 1,1-difluoroethane.^[6][7][8] Because of inhalant abuse, a bitterant is added to consumer canned air products.

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.^[9]

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.

See also

• List of refrigerants
• Canned air

References