The C-F Functionalization of Non-Activated Trifluoroethylarenes. Part II. Observation of Degradation in Water at 600 mpa
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Source: Photocatalytic low-temperature defluorination of PFASs
The Role of PFCs in the Biopolymerization of Hydrogen and Perfluoroalkyl Substituents
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Medicinal chemists are trying to make drug molecules that contain C–F bonds but can biodegrade safely once they leave the body. In some instances, PFCs have replaced harmful chemicals like chlorofluorocarbons. Non-fluorinated refrigerants are also available, including ammonia and carbon dioxide, but large-scale roll out will need regulatory input.
Such bonds lie at the heart of per- and polyfluoroalkyl substances (PFAS), a group of compounds, numbering in the millions, that are remarkably water-, heat- and greaseproof. Teflon was invented in the 1930s to make pans non-stick and keep rain out of our jackets. Varieties of cosmetics, fire-retardant foam, kitchen utensils, metal coatings, packaging, textiles and more all contain them.
Chemical catalysts based on light absorbers and a new method to clean up waste water and soils in the United States and other countries
The world has started to act to stop chemicals from entering the environment and clean up those already there. There is need for more action.
Both methods combine a catalyst with some relatively simple chemistry driven by the energy of visible light. In each case, the catalyst absorbs light that then triggers a reaction.
Chemist Garret Miyake at Colorado State University in Fort Collins and his colleagues use this absorbed energy to reduce the C–F bond to carbon–hydrogen — albeit not in Teflon1. The energy from this is used to break the bond and the molecule down to smaller parts at temperatures as low as 40 C. Both papers mark a huge step forward.
Next steps include using these ideas to develop catalysts that work in waste water or that can be used to clean up contaminated soils. If a method can be adapted so it is powered by sunlight, that would be of huge benefit.
The latest list of banned substances for persistent organic pollutants was reviewed by the international agreement that banned them.
The European proposal doesn’t yet extend to banning PFAS in applications such as medicine or transport, for the simple reason that these chemicals are still too useful and adequate alternatives are yet to be found. C–F bonds in pharmaceuticals allow molecules to remain stable, which is necessary for products’ shelf life.