Description
Freon�is a registered trade name
of�DuPont�which it uses for a number
of�halocarbon�products. They are stable nonflammable and
nontoxic gases or liquids which have typically been used
as�refrigerants�and as�aerosol propellants.
These include the�chlorofluorocarbons�(CFCs) implicated
in�ozone depletion, but also include newer refrigerants which
typically include fluorine instead of chlorine and do not deplete
the ozone layer.
The first CFCs were synthesized by�Fr�d�ric Swarts�in the
***0s. In the late ***0s a research team was formed by�Charles
Franklin Kettering�in�General Motors�to find a replacement
for the dangerous refrigerants then in use. The team was headed
by�Thomas Midgley, Jr.[1]�In ***8 they improved the synthesis
of CFCs and demonstrated their usefulness for such a purpose and
their stability and nontoxicity. Kettering patented a refrigerating
apparatus to use the gas, this was issued to�Frigidaire, a wholly
owned subsidiary of�General Motors.
[2]In ***0 General Motors �formed�Kinetic Chemicals�to
produce Freon. Their product was�dichlorodifluoromethane�and is
now referred to as \'Freon**2\', \'R**2\', or \'CFC**2\'. The
number after the R is a�refrigerant class number�developed
�to systematically identify single halogenated hydrocarbons, plus
there are R numbers assigned for other refrigerants besides
halocarbons.
Most uses of CFCs are now banned or severely restricted by
the�Montreal Protocol�as they are believed to be responsible
for ozone depletion.
[3]�Brands of Freon containing�hydrofluorocarbons�(HFCs)
instead have replaced many uses, but they too are under strict
control under the�Kyoto protocol�as they are super-greenhouse
effect gases. They are no longer used in aerosols, but to date no
suitable general use alternatives to the halocarbons have been
found for refrigeration which are not flammable or toxic, problems
the original Freon was devised to avoid.
