Fluorinated Compounds Block Radiation

NASA and Purdue University researchers have released a new study that could be used by Industrial Chemists to develop alternatives with less global warming potential than materials now in common use. The study looked at fluorine containing compounds such as hydrofluorocarbons, perfluorocarbons, hydrofluoroethers, hydrofluoroolefins and sulfur and nitrogen fluorides.

Fluorinated compounds are more efficient at blocking radiation in the atmospheric window, the frequency range in the infrared region of the electromagnetic spectrum through which radiation from Earth is released into space which helps cool the planet. When radiation is blocked instead of being released a greenhouse effect results, warming the planet.

The number and placement of fluorine atoms in a molecule's structure is instrumental in determining its ability to block radiation. Fluorine atoms are very electronegative and form highly polar bonds with carbon and sulfur. Fluorine atoms tend to change the bond polarity of molecules, modifying the bonds holding the atoms in the structure, which, in turn, effects how a molecule absorbs infrared radiation.

Fluorinated compounds also persist longer in the atmosphere than carbon dioxide and other major global warming agents. Even if fluorinated compounds are emitted in lower quantities they might have a cumulative effect and some don't break down for thousands of years.

Partha P. Bera, Joseph S. Francisco, Timothy J. Lee. Design strategies to minimize the radiative efficiency of global warming molecules. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.0913590107