نتایج جستجو برای: supported silyl chromate catalyst
تعداد نتایج: 236684 فیلتر نتایج به سال:
Magnetic nanoparticle-supported sulfanilic acid (MNPs-PhSO3H) has been used as an efficient catalyst for the preparation of 1,4-diazepines containing tetrazole ring. The catalyst has been characterized by FT-IR (Fourier-transform infrared spectroscopy), SEM (scanning electron microscope), XRD (X-ray diffraction) and VSM (vibrating-sample magnetometer). The present synthetic protocol provides se...
Concentrations of 0.25 and 0.5 mug/ml calcium chromate (CaCrO4-2H2O)dissolved in Dulbecco's medium were found to alter the growth behavior of BHK21 cells in culture. Treated cells grew as shortened fibroblasts and in random orientation. The changes detected during the first two weeks of culture in the presence of the metal became more pronounced as the number of growth passages increased. In ad...
Corrosion is the degradation or deterioration of metal components due to a reaction with the environment. Chromate conversion coating is applied to passivate metallic surface to slow down (and prevent to some extent) corrosion process. Chromate conversion process uses chromium compounds including hexavalent chromium, which is toxic, carcinogenic and hazardous to human health and environment. He...
Sequential reduction of chromate and nitrate, two competitive electron acceptors, has been demonstrated for strains of Pseudomonas genus for both planktonic cells and cells immobilised in agar layers on the surface of synthetic membrane. Denitrification occurs practically after chromate depletion. This order of reduction process is consistent with redox potentials of the respective reactions. I...
Silica-supported tantalum clusters (on average, approximately tritantalum) were formed by the treatment, in either H(2) or ethane, of adsorbed Ta(CH(2)Ph)(5); the supported catalyst is active for ethane conversion to methane and propane at 523 K, with the used catalyst containing clusters of the same average nuclearity as the precursor.
Synthesis of 2,4,5-triaryl-1H-imidazoles using a potent, green and reusable nano catalyst (FHS/SiO2)
A simple, green and efficient method for synthesis of 2,4,5-trisubstituted imidazoles is described via three-component cyclocondensation of benzil or benzoin, aldehyde and ammonium acetate by using the nano SiO2-supported ferric hydrogen sulfate (FHS/SiO2), as a catalyst, under solvent-free conditions. The nano SiO2 support and catalyst were characterized by X-ray diffraction (XRD), transmissio...
An efficient and eco-friendly method has been developed for the synthesis of 1,4 disubstituted 1,2,3-triazoles using the eggshell-supported-Cu(I) metformin complex as a natural and heterogeneous catalyst. The catalyst prepared is characterized by FT-IR spectroscopy, SEM, and ICP techniques. Terminal alkynes were successfully reacted with alkyl chloride and sodium azide in the presence of CuI im...
Highly colored (red) solutions of various enol silyl ethers and tetranitromethane (TNM) are readily bleached to afford good yields of alpha-nitro ketones in the dark at room temperature or below. Spectral analysis show the red colors to be associated with the intermolecular 1:1 electron donor-acceptor (EDA) complexes between the enol silyl ether and TNM. The formation of similar vividly colored...
Here we report that readily available silyl- and boron-based Lewis acids in combination with chiral copper catalysts are able to overcome the reactivity issues of unactivated enamides, known as the least reactive carboxylic acid derivatives, toward alkylation with organomagnesium reagents. Allowing unequaled chemo-reactivity and stereocontrol in catalytic asymmetric conjugate addition to enamid...
Synthesis of 2,4,5-triaryl-1H-imidazoles using a potent, green and reusable nano catalyst (FHS/SiO2)
A simple, green and efficient method for synthesis of 2,4,5-trisubstituted imidazoles is described via three-component cyclocondensation of benzil or benzoin, aldehyde and ammonium acetate by using the nano SiO2-supported ferric hydrogen sulfate (FHS/SiO2), as a catalyst, under solvent-free conditions. The nano SiO2 support and catalyst were characterized by X-ray diffraction (XRD), transmissio...
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