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水——不仅仅是溶剂,还能使偶联反应更绿色、更快速

已有 5612 次阅读 2007-11-1 08:24 |个人分类:催化科技导读


Water - not just a solvent


31 October 2007

Scientists in Germany have used water to improve the catalytic activity of coupling reactions making them greener and faster

The Suzuki-Miyaura coupling reaction is a powerful tool in organic synthesis, commonly used to make pharmaceutically active compounds. There has been recent interest in making the reaction greener by using water to eliminate the need for environmentally unfriendly organic solvents; however, until now this has not led to improvements in the coupling reaction.  

Herbert Plenio and Christoph Fleckenstein at the Technical University of Darmstadt have successfully used water not only to make the reaction more environmentally friendly but also to improve the coupling rate

 

water

 

'Water is primarily viewed as a green solvent,' said Plenio, 'but we wanted to show that water can be the solvent in which carbon-carbon bond forming reactions work much better than in organic solvents.' 

'Previous catalysts employed were not optimised for use in water,' explained Plenio. By synthesising highly water soluble ligands for the Pd catalyst, the team were able to perform the coupling reactions in pure water with much smaller amounts of catalyst. The catalysts were found to be 10-100 times more active than other systems. 

Plenio and Fleckenstein aim to develop this method for other reactions in the future. 'Improvements in catalysis will result in better synthesis - from an ecological as well as from an economic point of view,' Plenio said. 'The particular challenge is to design chemical transformations and chemical processes in such a manner that they produce a minimum amount of waste and require as little energy as possible. Catalysis is the tool to achieve just that.' 

Sarah Dixon 

Link to journal article

Aqueous cross-coupling: highly efficient Suzuki–Miyaura coupling of N-heteroaryl halides and N-heteroarylboronic acids
Christoph A. Fleckenstein and Herbert Plenio, Green Chem., 2007
DOI: 10.1039/b711965h

Also of interest

Faraday Discussion 141: Water - From Interfaces to the Bulk

27 - 29 August 2008, Edinburgh, United Kingdom

Water: the solvent for organic chemists?

Aqueous reactions could be the answer to the future of organic chemistry, say scientists in Canada and the US.

Catalyst problems dissolve away

The products of an important industrial reaction have been found to dissolve the catalysts themselves, dispensing with the need for co-solvents.

Organic synthesis goes supercritical

Swiss chemists have developed a greener and more efficient way of making an industrially important aldehyde.

http://www.rsc.org/chemistryworld/


 

相关链接:

Aqueous cross-coupling: highly efficient Suzuki–Miyaura coupling of N-heteroaryl halides and N-heteroarylboronic acids


Christoph A. Fleckenstein and Herbert Plenio


The palladium complex of the new disulfonated 9-(3-phenylpropyl)-9-PCy2-fluorene ligand is a highly active catalyst for aqueous Suzuki coupling reactions of N-heterocyclic chlorides and N-heterocyclic boronic acids; catalyst loadings of 0.02–0.1 mol% of Pd and two equiv. of phosphine result in the near quantitative formation of the respective coupling products at 100 °C.

Graphical abstract image for this article  (ID: b711965h)



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