نتایج جستجو برای: cu catalysts
تعداد نتایج: 92695 فیلتر نتایج به سال:
Highly stable monodispersed nano Cu hydrosols were facilely prepared by an aqueous chemical reduction method through selecting copper hydroxide (Cu(OH)2) as the copper precursor, poly(acrylic acid) (PAA) and ethanol amine (EA) as the complexing agents, and hydrazine hydrate as the reducing agent. The size of the obtained Cu colloidal nanoparticles was controlled from 0.96 to 26.26 nm by adjusti...
Steam reforming of methanol can be considered as an attractive reaction aiming at hydrogen production for PEM fuel cells. Although Cu/Al-contained catalysts are considerably evaluated in this reaction, further evaluation is essential to evaluate the impact of some promoters like Pt in order to find a comprehensively optimized catalyst. Pt promoter is employed with different methods in this ...
N,N'-Methylenebisacrylamide (MBAA), which is an important raw material in a widely industrial area, was synthesized using convenient catalysts. The synthesized monomer was fully characterized by the elemental analysis, fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), 1H-NMR, 13C-NMR, GC/MS, and high performance liquid chromatography (HPLC) analysis. Six differe...
[Structure: see text] A novel procedure for catalyst recycling is described. Copper(I)-based catalysts, equipped with an affinity tag, are isolated from crude reaction mixtures on the basis of quadruple hydrogen-bonding interactions using a resin functionalized with complementary affinity tags. Recycled catalysts were successfully used to catalyze a tandem Sonogashira coupling/5-endo-dig cycliz...
Carbon–carbon cross-coupling reactions are very important in the areas of material science and medicinal chemistry. Most current methods require expensive transition-metal catalysts (for example, based on Cu, Pd, Co, Ni, Pt, Ru, and Rh) and ligands (for example, phosphines). Early reports by Kharasch and Reinmuth in 1954 and then by Tamura and Kochi in 1971 suggested that inexpensive Grignard r...
the selective reduction of oximes with sodium borohydride (nabh4) in the presence of nano cu and charcoal was investigated. cu nanoparticles are widely used as catalysts; efficacious catalyst: copper and copper alloy nanometer feature high efficacy and selectivity, and can be used as catalyst in some reactions. we have shown that nabh4 in the presence of charcoal is an efficient protocol for th...
Herein, we report the function of copper sites in Cu-SSZ-13, Cu-ZSM-5 and Cu-Beta catalysts with same Si/Al ratio (14) Cu/Al (0.4) on selective catalytic reduction NO NH3 (NH3-SCR) reveal relationship between active (Cu sites, acid sites) activity. The results show that amount isolated Cu2+ ions directly determines formation strong Lewis reaction intermediate NO3− ions, thus affecting low-tempe...
Cheap and simple Cu/ZnO catalysts are very effective and recyclable for the synthesis of dimethylformamide (DMF) from CO(2), H(2), and dimethylamine, and a yield of 97% can be reached.
Immobilised [Cu(NHC)] catalysts are reported for the preparation of 1,2,3-triazoles. In addition to showing outstanding catalytic activity, the catalyst systems are easy to prepare and can be recycled many times.
The recent availability of shale gas has led to a renewed interest in C-H bond activation as the first step towards the synthesis of fuels and fine chemicals. Heterogeneous catalysts based on Ni and Pt can perform this chemistry, but deactivate easily due to coke formation. Cu-based catalysts are not practical due to high C-H activation barriers, but their weaker binding to adsorbates offers re...
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