نتایج جستجو برای: catalyst activity
تعداد نتایج: 1169846 فیلتر نتایج به سال:
to be fairly general and catalyst is easily separated by magnetic devices and can be reused without any apparent loss of activity for the reaction. fe3o4 nanoparticles were prepared by chemical coprecipitation method and was found to be a mild and effective catalyst for the efficient, one-pot, three-component synthesis of 2,4,5-trisubstituted imidazoles at room temperature under ultrasound irra...
in the current study, a magnetic inorganic–organic nanohybrid material (hpa/tpi-fe3o4) was produced and used as an efficient, highly recyclable and eco-friendly catalyst for the one-pot and multicomponent synthesis of 3,4-dihydroquinoxalin-2-amine, diazepine-tetrazole and benzodiazepine-2-carboxamide derivatives with high yields and in a short range of time (20–35 min). the nanohybrid catalyst ...
the effects of confinement in carbon nanotubes on fischer-tropsch (ft) activity, selectivity and lifetime of carbon nanotubes (cnts) supported iron catalysts are reported. a method was developed to control the position of the catalytic sites on either inner or outer surface of carbon nanotubes. tem analyses revealed that more than 80% of iron oxide particles can be controlled to be positioned a...
A new immobilized palladium-pyridine complex on γ-Fe2O3 magnetic nanoparticles was synthesized and characterized by SEM, TEM, TGA, ICP, XPS, XRD, FT-IR and CHN analysis. The catalytic activity of synthesized catalyst has been investigated in Heck, Suzuki and Sonogashira coupling reactions using a series of aryl halides. The catalyst was easily isolated from the reaction mixture by an external m...
nanomagnetic mgfe2o4 is an active, stable, and reusable catalyst for the oxidation of alcohols. the oxidation of various primary and secondary alcohols has been examined and related corresponding products were obtained in good yields. the reactions were carried out in the presence of water as solvent and oxone (at room temperature) or h2o2 (at 60 ºc) as an oxidant. the catalyst was investigated...
an efficient, mild and environmentally friendly method was reported for the synthesis of an efficient, mild and environmentally friendly method was reported for the synthesis of pyranopyroles from aryl aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate in the presence of catalytic amounts of methyl imidazolium hydrogen sulfate ([hmim][hso4]) as an efficient catalyst. these synth...
a simple and green synthetic strategy to prepare bao/tio2-zro2 as a solid base catalyst was reported. these materials with various amounts of bao were prepared by the adsorption method. the physical and chemical properties of bao/tio2-zro2 were investigated by x-ray diffraction, x-ray fluorescence, specific surface area and bjh pore size distribution, ft-ir spectroscopy, scanning electron micro...
The use of phosphites in second generation, ruthenium-based olefin metathesis pre-catalysts leads to an improvement in catalyst stability and activity at low catalyst loadings.
abstract in first part of this project, the use of a new and biguanid-like catalyst supported on silica as a recyclable catalyst provides a new route for the synthesis of a variety of arylalkylidene rhodanine derivatives through knoevenagle reaction in at present of solvent at room temperature. rhodanine derivatives and especially arylalkylidene rhodanines have proven to be attractive compound...
This article presents the research results on production and performance of palladium-only catalytic converters. Monolith is used as the catalyst carrier and gamma alumina as the substrate. Dipping method is used for monolith washcoating. Palladium as the active metal is impregnated on gamma alumina using wet impregnation to produce catalyst samples. The effects of factors such as percent solid...
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