CFC11

CFC-11, also known as trichlorofluoromethane, is a chlorofluorocarbon with the chemical formula CCl3F. It is a volatile, colorless gas at room temperature and was widely used in the 20th century as a refrigerant (often labeled R-11), a foam blowing agent for polyurethane insulation, and as a propellant in some aerosol products. Its applications made it one of the most common CFCs released to the atmosphere before controls.

Environmental impact and atmosphere: CFC-11 has a high ozone depletion potential. In the stratosphere, ultraviolet light breaks it down to release chlorine radicals, which catalytically destroy ozone molecules. This process contributes to thinning the ozone layer. CFC-11 also acts as a greenhouse gas with a high global warming potential relative to carbon dioxide, meaning it can contribute to long-term climate forcing.

Regulation and phase-out: CFC-11 is regulated under the Montreal Protocol on Substances that Deplete the Ozone Layer and its amendments. Global production and consumption were substantially phased out during the late 1990s and 2000s, with remaining uses limited to essential applications and servicing needs under strict control. In some periods there have been reports of illegal production or unreported use, prompting enforcement and monitoring to prevent further releases.

Properties and safety: CFC-11 is nonflammable and has relatively low acute toxicity, though inhalation can be hazardous. It is chemically persistent in the atmosphere, which contributes to its long-term environmental impact.

See also: ozone depletion, Montreal Protocol, ozone-depleting substances, refrigerants.