نتایج جستجو برای: heterogeneous catalytic
تعداد نتایج: 202404 فیلتر نتایج به سال:
Catalytic ozonation is a non-selective mineralization technology of organic matter in water by using active free radicals generated ozone degradation. can be divided into homogeneous catalytic reactions metal ions as catalysts and heterogeneous solid catalysts. Homogeneous has many problems, such low rate, secondary pollution caused the introduction utilization efficiency oxidants, which limit ...
Bi25FeO40 microtetrahedra, microcubes and microspheres were successfully synthesized by a simple hydrothermal process and by adding different additive agents. The formation mechanism of Bi25FeO40 microcrystals was proposed; the additive agents had important influences on the morphology and facet exposure of the products. The catalytic activity of these materials was evaluated by the degradation...
High pressure X-ray photoelectron spectroscopy (XPS) is used to characterize heterogeneous catalytic processes. The success of the new technique based on the possibility to correlate the catalytic activity and the electronic structure of an active surface. The dynamic character of a catalyst surface can be demonstrated impressively by this technique. In this contribution the basics of high pres...
The main disadvantage of biodiesel is its high price. The price of biodiesel depends on various factors such as the price of oil, methanol, catalyst, and labor. Among dif-ferent economic factors, oil accounts for the largest share of input costs of biodiesel production. In this study, first, suitable heterogeneous catalysts were identified for biodiesel production. Several studies were carried ...
Acid-base bifunctional heterogeneous catalysts were prepared by the reaction of an acidic silica-alumina (SA) surface with silane-coupling reagents possessing amino functional groups. The obtained SA-supported amines (SA-NR2) were characterized by solid-state 13C and 29Si NMR spectroscopy, FT-IR spectroscopy, and elemental analysis. The solid-state NMR spectra revealed that the amines were immo...
The electrocatalysts utilized as the prospective electrodes in fuel cells and high efficient energy conversion devices require both the interconnected channels for efficient electrolyte transportation and the superior catalytic activity with long service life. In this work, nanoporous gold with the rigid skeletons in three dimensions is partially decorated by porous platinum shell containing na...
In this work, an efficient and green procedure for the synthesis of various substituted 1,5-benzodiazepine derivatives via a one-pot three-component catalytic reaction has been described. The reaction was conducted between o-phenylenediamine, dimedone and aldehyde derivatives in the presence of CuFe2O4 nanoparticles as a magnetic heterogeneous nanocatalyst under ball-milling conditions at room ...
An environmentally benign procedure for the synthesis of vicinal nitrohydrins via the regioselective ring opening reaction of epoxides with nitrite anion using silica-bound 3-{2-[poly(ethylene glycol)]ethyl}-substituted 1-methyl-1H-imidazol-3-ium bromide as an effective heterogeneous phase transfer catalyst was described. Short reaction time, high yield of products, simple work-up proc...
5-Substituted-1H-tetrazoles were synthesized by the [3 + 2] cycloaddition of sodium azide with various nitriles in the presence of nickel zirconium phosphate (NiZrP) as an effective heterogeneous catalyst in dimethylsulfoxide at 120 °C. This method has the advantages of good to high yields, simple methodology and easy work-up. The catalyst can be recovered by centrifuging and reused with good y...
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