A variety of methods have previously been developed with the goal of attaching CO2 to various organic molecules to convert them into intermediate products for chemical syntheses. Indispensable to all of these techniques is a suitable catalyst that activates the CO2 for the reaction in question.
To date, no one has developed a general method for the catalytic methylation of amines by CO2. In this reaction, CO2 is bound to the nitrogen atom of the amino group and is converted (reduced) to a methyl group (–CH3). Amine methylation methods currently available generally depend on toxic substances.
Matthias Beller and his co-workers at the Leibniz Institute for Catalysis in Rostock have now described a catalyst that is able to generally convert carbon dioxide and diverse amines into products that are methylated at the nitrogen atom.
The secret of their success is a ruthenium complex that reacts with a special phosphoric ligand in situ to become an active catalyst. In addition, phenylsilane, an organosilicon compound, is used as a reducing agent.
For the actual reaction, the metal complex, ligand, and silane, are placed in an autoclave with toluene as solvent and the amine to be methylated. CO2 is introduced at a pressure of 30 bar and the mixture is stirred at 100 °C for several hours.
This new catalytic process makes it possible to selectively methylate almost all types of amines—secondary and primary, aromatic and aliphatic—in high yields. The amines are converted to the desired tertiary amines and diamines. Even urea can be used as a starting material. In contrast to many other known methylation methods, the presence of other functional groups, such as nitrile, olefin, ether, ester, or hydroxy groups pose no problem. They are not affected so protecting groups are not needed.
“We have demonstrated for the first time that the general methylation of organic substrates using silanes and CO2 as a simple carbon source is possible,“ says Beller. “The catalyst consists of a commercially available ruthenium complex and ligand formerly developed by our group.”About the Author
Author: Matthias Beller, Leibniz-Institut für Katalyse e.V., Rostock (Germany), http://www.catalysis.de/Beller-Matthias.239.0.htmlTitle: A General Catalytic Methylation of Amines Using Carbon Dioxide
Matthias Beller | Angewandte Chemie
Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz
Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences