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Magnetic Nanoparticles as Inductive Heating Elements in MicroreactorsContributor(s):Yasuhiro Uozumi, Yoichi M. A. Yamada, Toshihiro Watanabe
Leibniz Universität Hannover, Henkel KGaA, Düsseldorf and IFF GmbH, Ismaning, Germany
Inductive Heating for Organic Synthesis by Using Functionalized Magnetic Nanoparticles Inside Microreactors
Angew. Chem. Int. Ed. 2008, 47: 8950-8953
22 January 2009 (online)
flowthrough reactor - nanoparticles - inductive heating
SiO2-coated magnetic nanoparticles 1 and 3 (Fe3O4/Fe2O3 nanoparticles) were developed as heating elements for organic reactions, which were self-heated in an electromagnetic field. Thus, a microflow reactor (14 cm long, ø 9 mm) was filled with a mixture of magnetic nanoparticles 1 and sand (3:1, 5.5 g) without/with 400 mg of Pd-doped material 3 (2.8 mol%, 0.028 mmol Pd). The trans-esterification, Claisen rearrangement, the Buchwald-Hartwig amination, enyne metathesis and Wittig reaction were performed with 1 in an electromagnetic field under continuous-flow conditions to give the corresponding products in 75-98% yield (6 examples).
The Suzuki-Miyaura and Heck reactions were also carried out with Pd-doped magnetic nanoparticles 3 to afford the corresponding coupling products in 63-84% yield (five examples). The silica-coated Fe3O4/Fe2O3 magnetic nanoparticles 1 were prepared according to the reported procedure (M. R. Zachariah and co-workers Nanostruct. Mater. 1995, 5, 383; S. H. Ehrman et al. J. Mater. Res. 1999, 14, 4551).