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IUPAC name Dichlorodifluoromethane
Other names Carbon dichloride difluoride, Dichloro-difluoro-methane, Difluorodichloromethane, Freon 12, R-12, CFC-12, P-12, Propellant 12, Halon 122, Arcton 6, Arcton 12, UN 1028
CAS number 75-71-8
PubChem 6391
EINECS number 200-893-9
KEGG D03789
RTECS number PA8200000
InChI InChI=1/CCl2F2/c2-1(3,4)5
Molecular formula CCl2F2
Molar mass 120.91 g/mol
Appearance Colorless gas with odor-like odor
Density 1.486 g/cm³ at -29.8 °C
Melting point

-157.7 °C (115.5 K)

Boiling point

-29.8 °C (243.3 K)

Solubility in water 0.286 g/l at 20 °C
log P 2.16
Vapor pressure 577.6 kPa
kH 0.0025
Main hazards Dangerous for the environment (N)
NFPA 704
R-phrases R59
S-phrases S59, S61
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Dichlorodifluoromethane (R-12), usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane, commonly known as CFC, used as a refrigerant and aerosol spray propellant until its manufacture was discontinued and banned of new production in the United States and many countries in 1994, due to concerns about damage to the ozone layer. It is soluble in many organic solvents.


Physical properties

Property Value
Density (ρ) at -29.8 °C (gas) 6.25 kg.m-3
Density (ρ) at 15 °C (gas) 5.11 kg.m-3
Triple point temperature (Tt) -157 °C (116 K)
Triple point pressure (pt) 10 Pa (0.00010 bar)
Critical temperature (Tc) 112 °C (385 K)
Critical pressure (pc) 4.170 MPa (41.15 bar)
Critical density (ρc) 4.789 mol.l-1
Latent heat of vaporization (lv) 166.95
Specific heat capacity at constant pressure (Cp) at 30 °C 74 J.mol-1.K-1
Specific heat capacity at constant volume (Cv) at 30 °C 65 J.mol-1.K-1
Heat capacity ratio (κ) at 30 °C 1.138889
Vapor pressure (η) at -20 °C 151 kPa
Vapor pressure (η) at 0 °C 300 kPa
Vapor pressure (η) at 16 °C 500 kPa
Vapor pressure (η) at 20 °C 567 kPa
Vapor pressure (η) at 40 °C 960 kPa
Compressibility Factor (Z) at 21 °C 0.995
Viscosity (ρ) at 0 °C 11.68 μPa.s (0.01168 cP)
Thermal conductivity (k) at 0 °C 9.46 mW.m-1.K-1
Ozone depletion potential (ODP) 1.0 (CCl3F = 1)
Global warming potential (GWP) 8100 (CO2 = 1)

Usage as an aerosol

The use of chlorofluorocarbons as an aerosol in medicine, for example: USP-approved Albuterol, has been phased out by the U.S. Food and Drug Administration. The use of a different propellant known as hydrofluoroalkane, or HFA, which does not harm the environment has been chosen as the replacement. [1]


R-12 was primarily used in automobiles produced prior to 1994. For older vehicles retrofits to R-134a (1,1,1,2-tetrafluoroethane) are generally recommended. Retrofits usually include a complete flushing of the air conditioning system to remove the oil. The oils used for R12 and R134a are not generally compatible, although some oils designed for conversion to R134 are advertised as compatible with residual R-12. Additionally a new compressor, expansion valve, and dryer may be needed. In some cases, all new rubber hoses are needed. These components are usually aftermarket products which are certified as R-134a compatible. Some car manufacturers offer OEM replacement options for older R-12 air conditioning systems.

Alternative refrigerants

Below is a list of known "drop in" alternatives to R-12.

  • Freeze12
  • R-416a
  • R-414B
  • R-409A
  • R-406A
  • HC-12a

It should be noted the EPA does not refer to these as "drop-in" alternatives to R-12. The EPA has a section called "Misleading Use of Drop-In to Describe Refrigerants" which can be read here.


See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Dichlorodifluoromethane". A list of authors is available in Wikipedia.
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