“This is an important finding, not just academically but also for industry,” says chemist Per-Fredrik Larsson.
Catalysis is an incredibly valuable tool in the field of chemistry, with the Haber-Bosch process being one of the most important catalytic processes in the world. It is used to manufacture fertilizer, and calculations show that without it the world’s population would be just half of what it is today.
Precious metals are often used as catalysts in organic chemistry as they enable the production of many organic molecules with applications in areas such as pharmaceuticals and fine chemicals. As recently as 2010 Richard F. Heck, Ei-ichi Negishi and Akira Suzuki were awarded the Nobel Prize in Chemistry for their work on palladium catalysis.
“A problem with precious metals like palladium is that they are both expensive and harmful to the environment,” says Per-Fredrik Larsson at the Department of Chemistry and Molecular Biology.
Recent years have seen researchers evaluating several different non-precious metals – primarily iron and copper – as cheap and environmentally friendly alternatives to precious metals.
“Iron catalysts have proven to be a competitive alternative to precious metals for a number of reactions,” says Per-Fredrik Larsson. “An in-depth understanding of how these reactions work is incredibly important if we are to take this further. The results from our studies with iron led to several important insights into just how complex the chemistry can be.”
Larsson’s research group works not only with experimental methods but also with calculation models to understand how the chemistry works.
The trend for swapping precious metals for non-precious alternatives also has a flipside. It was discovered during experiments with iron catalysis in conjunction with professor Carsten Bolm of RWTH Aachen University in Germany that some reactions thought to be catalysed by iron had actually been catalysed by traces of copper in the commercially available iron source.
The fact that traces of copper could catalyse a number of different reactions was surprising as copper had previously been thought to be an ineffective catalyst requiring large quantities and high reaction temperatures.
“Our results show that copper has been given an undeservedly bad name as a catalyst,” says Per-Fredrik Larsson. “Given that copper chemistry is over a century old, it’s surprising that nobody’s realised this before.”
It is important in the pharmaceutical industry to limit the use of catalysts as the quantity of metal in the end-product is strictly regulated and the recovery process can be both difficult and expensive. As such, the finding that small quantities of copper can be used is an important discovery.
“We’ve developed and studied reactions with small quantities of copper and tried to understand how and why they work,” says Per-Fredrik Larsson.
The results and conclusions for iron and copper catalysts are a major contribution to this field of research and are important for its continued development.Contact:
Helena Aaberg | idw
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Es ist noch immer weitgehend unbekannt, wie die komplexen neuronalen Netzwerke im Gehirn aufgebaut sind. Insbesondere in der Hirnrinde der Säugetiere, wo Sehen, Denken und Orientierung berechnet werden, sind die Regeln, nach denen die Nervenzellen miteinander verschaltet sind, nur unzureichend erforscht. Wissenschaftler um Moritz Helmstaedter vom Max-Planck-Institut für Hirnforschung in Frankfurt am Main und Helene Schmidt vom Bernstein-Zentrum der Humboldt-Universität in Berlin haben nun in dem Teil der Großhirnrinde, der für die räumliche Orientierung zuständig ist, ein überraschend präzises Verschaltungsmuster der Nervenzellen entdeckt.
Wie die Forscher in Nature berichten (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005), haben die...
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Graphen besitzt extreme Eigenschaften und ist vielseitig verwendbar. Mit einem Trick lassen sich sogar die Spins im Graphen kontrollieren. Dies gelang einem HZB-Team schon vor einiger Zeit: Die Physiker haben dafür eine Lage Graphen auf einem Nickelsubstrat aufgebracht und Goldatome dazwischen eingeschleust. Im Fachblatt 2D Materials zeigen sie nun, warum dies sich derartig stark auf die Spins auswirkt. Graphen kommt so auch als Material für künftige Informationstechnologien infrage, die auf der Verarbeitung von Spins als Informationseinheiten basieren.
Graphen ist wohl die exotischste Form von Kohlenstoff: Alle Atome sind untereinander nur in der Ebene verbunden und bilden ein Netz mit sechseckigen Maschen,...
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22.09.2017 | Biowissenschaften Chemie