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Dichlorodifluoromethane
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
Identifiers
CAS number	75-71-8
PubChem	6391
EINECS number	200-893-9
KEGG	D03789
RTECS number	PA8200000
SMILES	C(F)(F)(Cl)Cl
InChI	InChI=1/CCl2F2/c2-1(3,4)5
Properties
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 mol.kg-1.bar-1
Hazards
Main hazards	Dangerous for the environment (N)
NFPA 704	0 1 0
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.

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.

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.

Time-series of atmospheric concentrations of CFC-12 (Walker et al., 2000).

• Haloalkane
• Halomethane
• Chlorofluorocarbon
• Tetrafluoromethane
• Trichlorofluoromethane
• Chlorotrifluoromethane
• Carbon tetrachloride (Tetrachloromethane)

• International Chemical Safety Card 0048
• Overview of Freon-12 and some of its environmental problems
• MSDS at Oxford University
• Thermochemistry data at chemnet.ru
• IR absorption spectra