980 resultados para facile


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Large-scale uniform Ag microtubes with high length diameter ratios have been first successfully synthesized by a facile approach, using low-cost super fine glass fibers as templates. The samples were characterized by SEM and XRD. The investigations showed that calcining or adding of PEG-1000 and alcohol could greatly improve the mechanical strength of the sample. Especially the products exhibited favorable catalytic properties during the degradation of Rhodamine B by NaBH4. (c) 2007 Elsevier B.V. All rights reserved.

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Two concise synthetic routes, being different in the glycosylation sequence, toward ginsenoside Ro (1) are developed. These syntheses feature the elaboration of the glucuronide residue at a later stage via the TEMPO-mediated selective oxidation and the installation of AZMB as a benzoylic neighboring participating group capable of being selectively removed afterward.

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Post-steaming treatment of Mo/HZSM-5 catalysts results in more molybdenum species migrating into and residing in the HZSM-5 zeolite channels. This is confirmed by XRF and XPS measurements. H-1 MAS NMR and Si-29 MAS NMR also demonstrate that the number of free Bronsted acid sites decreases in the Mo/HZSM-5 catalysts that underwent post-steaming treatment, compared to untreated Mo/HZSM-5 catalysts. As a result, the deactivation rate constant (kd) on the Mo/HZSM-5 catalyst after post-steaming treatment for 0.5 h is much smaller, and the catalyst therefore shows remarkable stability in the probe reaction of methane dehydro-aromatization. The results suggest that a more beneficial bi-functional balance between active Mo species for methane activation and acid sites for the following aromatization is developed over those Mo/HZSM-5 catalysts that have experienced post-steaming treatment for 0.5 h, in comparison with the untreated Mo/HZSM-5 catalysts.

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A facile and efficient one-pot synthesis of polysubstituted pyridin-2(1H)-ones from a variety of beta-oxo amides under Vilsmeier conditions is described, and a mechanism involving sequential halogenation, formylation and intramolecular nucleophilic cyclization is proposed

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A facile and efficient one-pot synthesis of substituted pyridine-2,4(1H,3H)-diones has been developed. Subjected to N,N-dimethylformamide dimethyl acetal (DMFDMA) in N,N-dimethylformamide at 120 ˚C, a series of acyl(carbamoyl)ketene S,S-acetals were converted into the corresponding substituted pyridine-2,4(1H,3H)-diones in high yields.

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We report a new approach for the synthesis of fluorescent and water-soluble Ag nanoclusters, using the common polyelectrolyte poly(methacrylic acid) as the template.

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A templateless, surfactantless, electrochemical approach is proposed to directly fabricate hierarchical flowerlike gold microstructures (HFGMs) on an indium tin oxide (ITO) substrate. The as-prepared HFGMs have been characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and cyclic voltammetry.

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A templateless, surfactantless, electrochemical route is proposed to directly fabricate hierarchical spherical cupreous microstructures (HSCMs) on an indium tin oxide (ITO) substrate. The as-prepared HSCMs have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD).