Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ruthenium catalyst goes with the flow

04.12.2014

A green route to key molecular building blocks delivers a continuous stream of products

An efficient catalyst has opened up an environmentally benign route to a family of molecular building blocks found in many pharmaceuticals and agrochemicals, a study shows.


A ruthenium catalyst packed into a reaction column can help to produce a steady stream of useful products. © 2014 A*STAR Institute of Chemical and Engineering Sciences

Molecular building blocks known as substituted amines contain a nitrogen atom bonded to at least two carbon atoms. They are often made by reacting nitrogen-containing amines with carbon-based molecules bearing a halogen atom such as chlorine, but this process tends to produce significant amounts of toxic waste.

Cleaner synthesis processes use a catalyst to connect the carbon chain of an alcohol molecule to the amine. But these catalysts, which contain metals such as ruthenium and iridium, usually dissolve in solution with the reactants. This makes it difficult to separate them from the products once the reaction is completed, wasting precious catalyst and increasing processing costs.

Balamurugan Ramalingam and colleagues at the A*STAR Institute of Chemical and Engineering Sciences have now developed a ruthenium catalyst that does not dissolve in solution, potentially making this reaction greener and more efficient[1].

The team used linker molecules containing phosphorus atoms to attach the ruthenium compound [Ru(p-cymene)2Cl2]2 to tiny polystyrene beads or granules of silica. These particles are easily filtered from the reaction mixture.

The researchers optimized the catalyst’s activity by testing different types of linker and varying the amount of ruthenium compound on each particle. They then used the best catalyst to join together a wide range of amines and alcohols, producing various substituted amines in good yields. The catalyst could be recycled over five reactions without much loss in activity, and very little ruthenium leached from the solid particles into solution. Ramalingam’s team then exploited the catalyst to produce a drug molecule called piribedil (used to treat Parkinson’s disease) in almost 100 per cent yield.

The catalyst beads can also be packed into hollow columns (see image) so that reagents flow over them to deliver a stream of products. Such continuous-flow systems are increasingly used to make pharmaceuticals or other high-value chemicals, as a more efficient and sustainable alternative to conventional ‘batch-by-batch’ processes.

The scientists slowly pumped an amine and an alcohol through the loaded column at a temperature of 120 °C. This delivered a continuous flow of product in 60–70 per cent yields for 21 hours, with virtually no loss of ruthenium. “In principle, the reaction could be scaled up to production scale, and the complete conversion could be achieved by recycling the reagents,” says Ramalingam. The team is now using the catalyst to make amine-based polymers.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Chemical and Engineering Sciences

Reference:
[1] Shan, S. P., Dang, T. T., Seayad, A. M. & Ramalingam, B. Reusable supported ruthenium catalysts for the alkylation of amines by using primary alcohols. ChemCatChem 6, 808–814 (2014).

A*STAR Research | ResearchSEA
Further information:
http://www.researchsea.com

More articles from Power and Electrical Engineering:

nachricht Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH

nachricht To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

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...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

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...

Im Focus: Deep inside Galaxy M87

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...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

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...

Im Focus: Microprocessors based on a layer of just three atoms

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>