Density functional theory (DFT) has been applied to study potential ammonia borane (AB) dehydrogenation pathways via new bifunctional ruthenium-based catalysts, alongside their computationally-designed iron-based counterparts (i.e., four catalysts), using the wB97XD (dispersion-included) functional. The efficiency of each catalyst was under scrutiny based on the addition of ammonia borane, with...

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...

this study examined the ability of the synthetic mordenite nanocrystal to remove tl(iii) and as(iii) from an aqueous solution. the determination of the concentration changes of h+ and oh- quantities in the acidic (ph 3) and alkali (ph 9) treated mordenite nanocrystals were done by the potentiometric titration curves. the maximum uptake capacities (qmax) of these metal ions using the mordenite i...

In the present study, the adsorption behaviors of mordenite (a common zeolite) with respect to Cu 2+ and Ni 2+ from aqueous solutions were investigated. The sorption data followed the Freundlich and Langmuir isotherms. The maximum sorption capacities were found to be 9.778 and 5.371 mg/g at pH 6, initial concentration of 40 mg/L and temperature of 30 for Cu 2+ and Ni 2+ , respectively. The kine...

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.

Nanocrystals of zeolites with shortened diffusional pathways compared to bulk counterparts are attractive catalysts, but their direct synthesis often remains challenging and expensive. Here, we describe the utility p-phenylenedimethylene–bis(trimethylammonium) dichloride, an organic diquaternary ammonium compound that can be easily prepared, as effective structure-directing agent (OSDA) for obt...

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...