The cfc
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Publicado: 6 de octubre de 2010
Cfc
The beginning of the CFC(chlorofluorocarbons) era started in 1928, when CFC' were invented by a Du Pont chemist. CFC' were best known as"freons" and became famous as a safe, nonflammable refrigerant. It's invention became a great triumph when Freon took the place of sulfur dioxide orammonia which was used as the working liquid in refrigerators. It eventually became widely used in automobile air conditioners and nontoxic propellants inaerosol cans. It's insulating properties also was used for blowing agents for plastics and foam cups.
Thus CFCs became used all over the world and itsbusiness got bigger and bigger until late in 1973. Sherwood Rowland and Mario Molina, two distinguished chemists, came up with a surprising result inhis calculations concerning the CFCs and ozone layer. CFCs are basically inactive in the troposphere(around the altitude of 50,000 feet) so it wouldgradually drift upward until they reached the mid-stratosphere.(about 100,000 feet) At this point CFCs would be broken down by short-wavelengthultraviolet radiation from the sun. This radiation is the one which would not reach the lower atmosphere in large amounts because of the ozone layer. Whenthese CFCs do brake down, they released atomic chlorine which then would react with the ozone and convert it back into plain oxygen. The even worsepart of all this is that these chlorine molecules do not become inactive after the first reaction with the ozone and would be available to destroy more o
The beginning of the CFC(chlorofluorocarbons) era started in 1928, when CFC' were invented by a Du Pont chemist. CFC' were best known as"freons" and became famous as a safe, nonflammable refrigerant. It's invention became a great triumph when Freon took the place of sulfur dioxide orammonia which was used as the working liquid in refrigerators. It eventually became widely used in automobile air conditioners and nontoxic propellants inaerosol cans. It's insulating properties also was used for blowing agents for plastics and foam cups.
Thus CFCs became used all over the world and itsbusiness got bigger and bigger until late in 1973. Sherwood Rowland and Mario Molina, two distinguished chemists, came up with a surprising result inhis calculations concerning the CFCs and ozone layer. CFCs are basically inactive in the troposphere(around the altitude of 50,000 feet) so it wouldgradually drift upward until they reached the mid-stratosphere.(about 100,000 feet) At this point CFCs would be broken down by short-wavelengthultraviolet radiation from the sun. This radiation is the one which would not reach the lower atmosphere in large amounts because of the ozone layer. Whenthese CFCs do brake down, they released atomic chlorine which then would react with the ozone and convert it back into plain oxygen. The even worsepart of all this is that these chlorine molecules do not become inactive after the first reaction with the ozone and would be available to destroy more o
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