نتایج جستجو برای: recoverable catalyst
تعداد نتایج: 46271 فیلتر نتایج به سال:
in this paper, fe3o4-chitosan nanoparticles were prepared by the immobilization of chitosan on the surface of fe3o4 nanoparticles. then, the 5-substituted hydantoins were synthesized from the condensation of aldehyde derivatives, ammonium carbonate and zinc cyanide as a well-known cyanating agent by the magnetic fe3o4-chitosan nanoparticles under neat conditions. fe3o4-chitosan nanocatalyst as ...
the magnetically recoverable fe3o4 nanoparticle and the supported brønsted acidic ionic liquid 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate (fe3o4-il-hso4) were synthesized and used as efficient magnetic catalysts for the regioselective thiocyanation of aromatic and heteroaromatic compounds at room temperature in water: ethanol. this procedure provided the target thiocyanat...
a series of fe3o4 supported on mesoporous fdu-12 silica systems were prepared by the hydrothermal conditions. the surface properties of the functionalized catalyst were analyzed by a series of characterization techniques like ftir, xrd, n2 adsorption–desorption and tem. xrd and adsorption–desorption analysis shows that the mesostructure of fdu silica remains intact after fe3o4 modifications, wh...
A magnetically recoverable catalyst consisting of Mn (III) salophen complex was prepared. The synthesized catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Fourier transform infrared (FT-IR). The immobilized catalyst was shown to be an ef...
A magnetically recoverable catalyst consisting of Mn (III) salophen complex was prepared. The synthesized catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Fourier transform infrared (FT-IR). The immobilized catalyst was shown to be an ef...
Chiral amine and polyoxometalate (POM) acids were combined to give highly efficient, stereoselective, and recoverable enamine-based catalysts. Less than 1 mol % of chiral amine loading was sufficient for good catalytic activity, and the catalyst could be recovered and reused 6 times with unchanged enantioselectivity and slightly decreased activity.
An active, recoverable, and recyclable nanocluster catalyst, Au25(SR)18(-), has been developed to catalyze the formation of α,β-unsaturated ketones or aldehydes from propargylic acetates. The catalytic process has been proposed to be initialized by an SN2' addition of OH(-). Moreover, a dramatic solvent effect was observed, for which a rational explanation was provided.
A magnetically recoverable chiral rhodium catalyst exhibited excellent catalytic activity and enantioselectivity in asymmetric transfer hydrogenation of aromatic ketones in aqueous medium, which could be recovered easily via a small magnet and used repetitively ten times without obviously affecting its enantioselectivity.
A new practical synthesis of triaryl and trisindolylmethanes under solvent-free reaction conditions.
An efficient and practical synthesis of triaryl and trisindolylmethanes is reported via the bisarylation of aryl aldehydes with activated arenes. The new method features mild solvent-free reaction conditions, in most cases nearly stoichiometric reagent ratios, catalytic amount of the readily available, easily-handled, recoverable and reusable Brønsted acid catalyst o-benzenedisulfonimide.
We have successfully prepared an unsymmetrical analogue of a Katsuki-type salen ligand having a single hydroxyalkyl group at its 6-position, and also its Mn(III) complex; attachment of the complex to a polymer gives a highly enantioselective and recoverable catalyst for epoxidation of 1,2-dihydronaphthalene.
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