Macro Group UK Young Researchers’ Meeting, April 2004, Sheffield, UK
|Polymer-supported catalysts for greener synthesis|
|Tạp chí Macro Group UK Young Researchers’ Meeting 2004 ; April ():|
|Tác giả||Nam T. S. Phan, David H. Brown, Peter styring|
|Nơi thực hiện||Department of Chemical and Process Engineering, The University of Sheffield, Mappin Street, Sheffield, UK S1 3JD|
|Từ khóa||micro flow reactor, cross-coupling reaction, palladium, leaching, polymer-supported|
|DOI [ URL] [ PDF]|
Solid-supported catalysts derived from homogeneous nickel(II) and palladium(II) non-symmetrical salen-type coordination complexes have been prepared and shown to be effective in the heterogeneous catalysis of carbon-carbon cross-coupling reactions. The nickel catalyst has been used in a room temperature Kumada reaction and the palladium catalyst in the Suzuki and Heck reactions at elevated temperatures. The catalysts could be easily separated from the reaction mixture and reused after washing without a significant degradation in activity. Leaching of the metal into solution from the supported catalysts during the course of the reaction proved almost negligible. The Suzuki reaction could also be carried out in aqueous media with high water content. The complexes were prepared by improved methods and characterised by spectroscopic techniques. Comparisons between the solid-supported catalysts and their homogeneous analogues are reported. The single-crystal structure determinations of the nickel and palladium complexes [M(salenac-OH)] [M = Ni, Pd; salenac-OH = 9-(2',4'-dihydroxyphenyl)-5,8-diaza-4-methyl-non-2,4,8-trienato](-2)] are reported. The Kumada and Suzuki reactions using the supported catalysts were carried out in a continuous mini flow reactor. Reasonable conversions could be achieved in a matter of minutes, compared to similar conversions obtained after 24 hours in a conventional batch reaction, albeit on a much smaller scale. The mini flow reactor system provides a powerful tool in catalyst screening and a route to high throughput synthesis.