Chlorofluorocarbons (CFCs)

Chlorofluorocarbons (CFCs)

Chlorofluorocarbons (CFCs) (also known as Freon) are non-toxic,

non-flammable and non-carcinogenic. They contain fluorine atoms,

carbon atoms and chlorine atoms. The 5 main CFCs include CFC-11

(trichlorofluoromethane - CFCl3), CFC-12 (dichloro-difluoromethane -

CF2Cl2), CFC-113 (trichloro-trifluoroethane - C2F3Cl3), CFC-114

(dichloro-tetrfluoroethane - C2F4Cl2), and CFC-115

(chloropentafluoroethane - C2F5Cl).

CFCs are widely used as coolants in refrigeration and air

conditioners, as solvents in cleaners, particularly for electronic

circuit boards, as a blowing agents in the production of foam (for

example fire extinguishers), and as propellants in aerosols. Indeed,

much of the modern lifestyle of the second half of the 20th century

had been made possible by the use of CFCs.

Man-made CFCs however, are the main cause of stratospheric ozone

depletion. CFCs have a lifetime in the atmosphere of about 20 to 100

years, and consequently one free chlorine atom from a CFC molecule can

do a lot of damage, destroying ozone molecules for a long time.

Although emissions of CFCs around the developed world have largely

ceased due to international control agreements, the damage to the

stratospheric ozone layer will continue well into the 21st century.

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Chlorofluorocarbons (CFCs) are organic compounds that contain carbon,

chlorine, and fluorine atoms. CFCs are highly effective refrigerants

that were developed in response to the pressing need to elim...

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...and may contain chlorine. Halons have

been used primarily as propellants in fire extinguishers. Because of

their bromine content they are even more destructive to ozone than

CFCs, and an amendment to the Montreal Protocol banned their use by

1994.

Hydrochlorofluorocarbons (HCFCs) are organic compounds that are

similar to CFCs but less destructive to ozone. HCFCs consist of

carbon, hydrogen, chlorine and fluorine. They are used as replacements

for CFCs, but are to be phased out by the year 2020, as specified by

the Montreal Protocol as amended, when they are expected to be

replaced by hydrofluorocarbons (HFCs). HFCs are organic compounds that

contain hydrogen, carbon and fluorine. HFCs, which do not contain

chlorine, do not have any potential for the destruction of ozone, and

so are suitable replacements for CFCs.