Difluoromethane
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| Names | |||
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| IUPAC name
Difluoromethane
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| Other names
Methylene fluoride, Methylene difluoride, Carbon fluoride hydride, HFC 32, R 32, FC 32, Freon 32, UN 3252
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| Identifiers | |||
3D model (JSmol)
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| ECHA InfoCard | 100.000.764 | ||
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PubChem CID
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| RTECS number |
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CompTox Dashboard (EPA)
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| Properties | |||
| CH2F2 | |||
| Molar mass | 52.02 g/mol | ||
| Appearance | Colorless gas | ||
| Density | 2.72 kg/m3 at 15 °C (59 °F) 2.163 kg/m3 at 21.1 °C (70 °F) | ||
| Melting point | −136 °C | ||
| Boiling point | −51.6 °C | ||
| Vapor pressure | 1518.92 kPa at 21.1 °C (70 °F) | ||
| Hazards | |||
| NFPA 704 (fire diamond) | |||
| Supplementary data page | |||
| Difluoromethane (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Difluoromethane, also called HFC-32 or R-32, is an organic compound of the dihalogenoalkane variety. It is based on methane, except that two of the four hydrogen atoms have been replaced by fluorine atoms. Hence the formula is CH2F2 instead of CH4 for normal methane.
Physical properties
| Property | Value |
|---|---|
| Critical pressure (pc) | 5.83 MPa |
| Critical temperature (Tc) | 78.45 °C (351 K) |
| Compressibility factor (Z) | 0.9863 |
| Heat capacity at constant pressure (Cp) at 21 °C (70 °F) | 0.043 kJ·mol−1·K−1 |
| Heat capacity at constant volume (CV) at 21 °C (70 °F) | 0.034 kJ·mol−1·K−1 |
| Heat capacity ratio (κ) | 1.253 |
Uses
Difluoromethane is a refrigerant that has zero ozone depletion potential. Difluoromethane in an azeotropic mixture with pentafluoroethane is known as R-410A, a common replacement for various chlorofluorocarbons (aka Freon) in new refrigerant systems. Although it has zero ozone depletion potential, it has high global warming potential, 550 times that of carbon dioxide, based on a 100-year time frame [1].