ChemWeb Newsletter

Not a subscriber? Join now.April 26, 2018

contents
publishers' select

A HIGH-INTEREST CHEMWEB MEMBER BENEFIT

Free Selected Full Text Articles

ChemWeb members now have access to selected full-text articles from Chemistry publishers, including Wiley, Elsevier, Springer, Taylor & Francis, and the Royal Society of Chemistry. Members can download a selection of articles covering a broad range of topics direct from the pages of some of the most respected journals in Chemistry. Explore some of the latest research or highly cited articles. Not yet a ChemWeb member? Membership is free, and registration takes just a minute.



overview

This week, The Alchemist sees complexity in the simplest of molecules, figures out how to use graphene to make green concrete, works up an appetite for plastic waste, shines light on diamonds' hint of ancient planetary embryos, carries out some exhaustive testing, and gets the lay of the land from space.




Linear polyenes are an essential unit of studies of photoisomerization. Their relatively straightforward molecular structure, potential for electrical conductivity, and role in vision make them even more important. However, the simplest, 1,3-butadiene, has puzzled chemists for decades because of its complex excited-state electronic structure and its ultrafast dynamics. It is, in some ways, the "missing link" between ethylene with its single double bond, and the longer linear polyenes that have three or more. Now, an experimental team headed by Albert Stolow at the University of Ottawa and the National Research Council of Canada has solved the dynamic problem filling in the details between the single bond ethylene and the three-or-more polyenes.





A more durable and stronger concrete that is also more environmentally
benign has been developed by scientists at the University of Exeter, UK.
The key ingredient of their new formulation for this ubiquitous
construction material is the now well-known carbon allotrope, graphene.
The new composite material, which is more than twice as strong and four
times more water resistant than existing concretes, can be used directly
by the construction industry on building sites, the team suggests.
Ironically, the use of graphene actually reduces the carbon footprint of
making the concrete.





A genetically modified enzyme that can digest polymers could help with one of the biggest environmental problems of our age, the vast quantities of plastic waste we have generated over the last few decades and continue to produce. The enzyme specifically degrades polyethylene terephthalate (PET), the commonest thermoplastic and one of the most widely used polymers used in clothing, food and drink packaging in combination with glass fiber for engineering resins. The ubiquity of plastic has become an increasing problem in recent years with the recognition of the huge amount of waste plastic that ends up in the world's waterways and oceans. Of course, one of the benefits of polymers is their robustness and stability but this also underpins one of the biggest problems in their disposal. “We can all play a significant part in dealing with the plastic problem, but the scientific community who ultimately created these ‘wonder-materials’, must now use all the technology at their disposal to develop real solutions,” says John McGeehan of the University of Portsmouth, UK who worked alongside Gregg Beckham of the US Department of Energy’s National Renewable Energy Laboratory NREL.





In October 2008, an asteroid entered the Earth’s atmosphere and shattered above Nubian Desert in Sudan raining down multiple fragments across the desert. Now, researchers from EPFL in Lausanne, Switzerland, have examined a slice of one of those meteorites and discovered that it contains large diamonds that are thought to have formed at high pressure. The implication of the study is that these chunks of crystalline carbon have to have been formed in a parent body of that asteroid that was a planetary embryo between the diameter of Mercury and Mars. Models of planetary formation predict that such planetary embryos would have existed during the first million years or so of our solar system. The study detailed in the journal Nature Communications adds to the evidence for such heavenly bodies.





In situ mass spectrometry and X-ray diffraction data sensitive to metal nanoparticle surface structure have been combined to investigate the ambient pressure carbon monoxide oxidation over a platinum-rhodium catalyst. Given that catalytic converters are increasingly important in cleaning exhaust emissions from vehicles and even in industrial exhaust scrubbing there is an increasing need to find ways to improve their efficiency and efficacy at removing noxious gases, such as nitrogen oxides and carbon monoxide from such exhausts. It appears from this latest study that nanoparticles with lots of edges rather than smoother particles can sidestep poisoning to some degree and stay active longer, pointing to a new approach to designing catalyst particles.





Isaac Larsen at the University of Massachusetts Amherst has been awarded a three-year, $265,000 New Investigator Program grant by NASA's Earth Science Division. The grant will allow the geochemist and his team to study Midwest soil erosion on an unprecedented scale by taking a view of the problem from space. Larsen proposes to use high-resolution images to map out the presence and absence of topsoil in areas where images are available from the right time of year - either after fall harvest and before it snows, or after the snow melts and before spring planting with specific attention on the "organic", carbon-rich part of the soil that is so vital to fertility and productivity.