نتایج جستجو برای: iron catalysts
تعداد نتایج: 173649 فیلتر نتایج به سال:
Through catalytic epoxidation and aziridination of olefins versatile synthetic intermediates and subunits of biologically active compounds and pharmaceuticals –epoxides and aziridines– can be obtained. The focus of this review is on recent advances in the epoxidation and aziridination of challenging terminal alkenes with respect to safety of solvents or reagents used and atom economy aspects, a...
Iron-substituted MFI, Y and USY zeolites prepared by two preparation routes-classical ion exchange and the ultrasound modified ion-exchange method-were characterised by micro-Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet (UV)/visible diffuse reflectance spectroscopy (UV/Vis DRS). Ultrasound irradiation, a new technique for the preparation of th...
Several Fe-Ce catalysts for FT synthesis were prepared following two different methods: coprecipitation from Fe and Ce nitrate solutions and a physical mixture of pure Fe and Ce oxide precursors. Previously to CO hydrogenation, catalysts were activated in syngas (50 ml/min, H2/CO = 2) at 553 K for 1 h at atmospheric pressure. The iron phases developed after activation pretreatment were identifi...
We have demonstrated that iron porpholactones could be effective catalysts for nitrogen atom transfer reactions such as aziridination of alkenes and amidation of alkanes using organic azides.
The effects of four widely employed “antioxidants” on iron-mediated hydroxyl radical formation and lipid peroxidation were studied in aqueous model systems. Iron and copper served as catalysts for the reactions which oxidized ascorbic acid and alpha-tocopherol and reduced oxygen. Ferrous ion spontaneously reduced oxygen to 0; (superoxide anion radical) which led to .OH (hydroxyl radical) and Hz...
Knölker's iron-based catalysts have some value in "green" transformations given the relatively low toxicity of iron compared to more commonly used precious-metal catalysts. Density functional methods have been used to extensively explore the use of an iron catalyst for hydrogen-transfer processes. Several inner- (with substrate coordination) and outer-sphere mechanisms (with no substrate coordi...
Enantioselective, intermolecular benzylic C-H amination catalysed by an engineered iron-haem enzyme.
C-H bonds are ubiquitous structural units of organic molecules. Although these bonds are generally considered to be chemically inert, the recent emergence of methods for C-H functionalization promises to transform the way synthetic chemistry is performed. The intermolecular amination of C-H bonds represents a particularly desirable and challenging transformation for which no efficient, highly s...
A series of complexes containing the iron-cyclopentadienone structure were prepared by cyclising bis-propargylic alcohols and their derivatives with iron pentacarbonyl. The resulting complexes were characterised and tested in the catalysis of ketone reduction and alcohol oxidation. The complexes are competent catalysts for ketone reduction and alcohol oxidations.
A highly active iron catalyst for the hydrogenation of carbon dioxide and bicarbonates works under remarkably low pressures and achieves activities similar to some of the best noble metal catalysts. A mechanism is proposed involving the direct attack of an iron trans-dihydride on carbon dioxide, followed by ligand exchange and dihydrogen coordination.
In this Letter, we report, for the first time, using polymer single crystal as magnetically recoverable support for nanoparticle catalysts. This catalyst system is composed of polymer single crystal, platinum nanoparticles, and iron oxide nanoparticles, which act as support, catalysts, and magnetic responsive materials, respectively. Platinum nanoparticles and iron oxide nanoparticles were bond...
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