At sea level, the strong C-F bond makes fluorocarbons thermally and chemically stable. As a result, fluorocarbons have been used in many commercial applications including refrigerants, pesticides and non-stick coatings. In the upper atmosphere, however, high-energy photons and highly reactive ozone molecules can break apart fluorocarbons, with the well-known consequence of a depleted ozone layer and increased ultraviolet radiation at ground level. A determined chemist can break down fluorocarbons at ground level with certain organometallic compounds, but the reactions take a long time at very high temperatures. Other known reagents are both highly toxic and inefficient, so chemists have been searching for an economical and environmentally friendly method to dispose of fluorocarbons.
Reasoning that the problem already may have been solved by nature, the NIST/Philip Morris team looked to an enzyme called fluoroacetate dehalogenase used by a South African bacterium, Burkholderia sp. The enzyme enables the bacterium to pull the fluoride ion out of sodium fluoroacetate (disrupting a poisonous compound) at room temperature and without problematic metal ions. Enzymes are giant molecules, evolved to survive and work in the complex environment of a living organism; they can be difficult and expensive to adapt to an industrial process. Instead, the research team applied basic quantum mechanical theory of electron structures in molecules, together with the example of a known molecule that binds to and extracts chlorine ions, to calculate the make-up and geometry of the critical "active site" in the enzyme that does the work. They then designed in software a large ring-shaped molecule to hold those components in just the right orientation to break the C-F bond in methyl fluoride, a simple fluorocarbon.
Researchers at the University of Texas now are synthesizing the new molecule to test its effectiveness. If it matches theoretical predictions, it will be the first example of a simple organic molecular system able to break C-F bonds without extreme temperature and pressure conditions, and a demonstration of a novel technique for designing man-made molecules that can mimic the extraordinary selectivity and chemical activity of natural enzymes. Notes lead researcher Carlos Gonzalez, "All of these useful things are in nature, you just have to find them and make them more efficient."
Michael Baum | EurekAlert!
Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine
New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
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26.06.2017 | Physics and Astronomy
26.06.2017 | Information Technology