�Everybody loves the fashion breakfast egg conveniently sloping trough off of Teflon without leaving whatever pesky pieces of testicle in the pan. Indeed, the carbon-fluorine bond at the heart of Teflon cookware is so helpful we as well use it in vesture, lubricants, refrigerants, anesthetics, semiconductors, and even blood substitutes. But the very forcefulness of the C-F bond that makes it utile in so many applications also gives it formidable greenhouse gas pedal effects that persist in nature. In a groundbreaking ceremony study in Science, Brandeis scientists theme they have identified a catalyst that efficiently breaks the C-F bond and converts it to a carbon-hydrogen bond, rendering it harmless to the environment.
Chlorofluorocarbons (CFCs or freons) are harmful to the ozone layer. Hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) are generating concern because they ar considered super-greenhouse gases, with great potential drop to strong the surround by trapping solar radiation and left over virtually perdurable in the atmosphere.
"The C-F bond is difficult to transform into other bonds under mild conditions because it is inert and unreactive; it's a challenge to chemists," said lead author chemist Oleg Ozerov, who conducted the inquiry with post doc Christos Douvris. "But we found a way to take a C-F alliance that you can do very little with and break it and commute it cleanly into something else at room temperature."
With research supporting from the Department of Energy, Sloan Foundation, and Research Corporation, Ozerov identified a new catalytic process for a class of carborane-silylium compounds that causes the bonds in instance HFCs to react at room temperature, swapping their carbon-fluorine bonds for carbon-hydrogen bonds. The silylium catalyst performs the critical labor of breakage the C-F bond by abstracting the fluoride from the fluorocarbon and attaching it to a atomic number 14 atom. The end cartesian product is a compound with a silicon-fluorine bond, which is no longer a greenhouse threat.
This finding could eventually lead to large-scale reactions to convert environmental pollutants that contain C-F bonds into products that could be reused or destroyed without special equipment.
"Conversion of PFCs remains a challenge, and our research efforts ar directed at designing even more dynamic catalysts, capable of PFC activation," aforesaid Ozerov.
Source: Laura Gardner
Brandeis University
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Saturday, 6 September 2008
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