Dichlorodifluoromethane

Dichlorodifluoromethane is a chlorofluorocarbon with formula CCl₂F₂, formerly used widely as a refrigerant and aerosol propellant. It is commonly known as CFC-12 or Freon-12.

Chlorofluorocarbon: A compound containing carbon, chlorine, and fluorine, once widely used in refrigeration and aerosol products. CFC-12 belongs to this family of compounds.
Montreal Protocol: A 1987 international treaty that phases out production and consumption of ozone-depleting substances. The treaty’s controls sharply curtailed production of CFC-12 and related chemicals.
Refrigerant: A working fluid that transfers heat through evaporation and condensation in a refrigeration or cooling system. CFC-12 served as the working fluid in many refrigeration systems.
Thomas Midgley Jr.: An American engineer and inventor associated with the development and promotion of leaded gasoline and CFC refrigerants. Midgley helped develop and publicly demonstrate the early CFC refrigerant that became CFC-12.
Ozone depletion: The reduction of ozone in the stratosphere, caused in part by chlorine released from human-made chemicals. Ultraviolet light breaks down CFC-12 and releases chlorine that catalytically destroys ozone.
Antarctic ozone hole: A seasonal, severe thinning of stratospheric ozone over Antarctica. CFC-derived chlorine contributes to the chemistry behind the ozone hole.
Vapor-compression refrigeration: A refrigeration cycle that moves heat using a circulating fluid compressed and expanded between liquid and vapor states. CFC-12’s thermodynamic properties suited it to this widely used refrigeration cycle.
Frigidaire: An American appliance brand founded as a refrigerator manufacturer in 1918. Frigidaire’s research program produced CFC refrigerants, including CFC-12, as safer alternatives to earlier fluids.
Stratospheric ozone layer: A region of the stratosphere with elevated ozone concentrations that absorbs much of the Sun’s ultraviolet radiation. CFC-12 reaches this layer, where its chlorine-containing breakdown products affect ozone.
Ozone depletion potential: A relative measure of a substance’s capacity to deplete stratospheric ozone, compared with a reference chemical. CFC-12 is the reference substance assigned an ozone depletion potential of 1.

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FluorocarbonBroader topic: R-12 exemplifies the refrigeration utility and ozone consequences of an early CFC.