- Freon
Freon is
DuPont 's trade name for its odorless, colorless, nonflammable, and noncorrosivechlorofluorocarbon andhydrochlorofluorocarbon refrigerant s, which are used inair conditioning andrefrigeration systems.History
Freon was initially developed in the early 20th century as an alternative to the toxic gases that were previously used as
refrigerants , such asammonia ,chloromethane , andsulfur dioxide . Freon, in this case dichlorodifluoromethane, was invented byThomas Midgley, Jr. with co-inventorCharles Kettering . [ [http://inventors.about.com/library/inventors/blfreon.htm Inventors] accessed December 21, 2007] Each Freon product is designated by a number; for instance, Freon-11 istrichlorofluoromethane , while Freon-12 isdichlorodifluoromethane .Controversy
In the 1990s, most uses of Freon chlorofluorocarbons (CFCs) were phased out due to the negative effects that CFCs have on the Earth's
ozone layer . DuPont began to phase out its production of Freon CFCs in the 1980s after federal regulatory agencies banned their use. [ [http://heritage.dupont.com/touchpoints/tp_1930-3/depth.shtml "1930: Freon", "DuPont Heritage"] accessed June 25, 2008] The interim replacements for CFCs are hydrochlorofluorocarbons (HCFCs), which contain chlorine that depletes stratospheric ozone, but to a much lesser extent than CFCs. [ [http://www.epa.gov/ozone/defns.html "Ozone Layer Depletion", "U.S. Environmental Protection Agency"] accessed June 25, 2008] Ultimately, hydrofluorocarbons (HFCs) will replace HCFCs with essentially no ozone destruction, yet they are classed as greenhouse gases. DuPont began producing hydrofluorocarbons as alternatives to Freon in the 1980s. These included Suva refrigerants and Dymel propellants. [ [http://heritage.dupont.com/touchpoints/tp_1930-3/depth.shtml "1930: Freon", "DuPont Heritage"] accessed June 25, 2008] Any of these gases that are used as refrigerants are designated by an "R-" number and colloquially known as "Freon", whether they are made by DuPont or another supplier.Footnotes
ee also
*
Haloalkane , a group of chemical compounds
*List of refrigerants
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