نتایج جستجو برای: cu catalysts

تعداد نتایج: 92695  

Journal: :Nanoscale 2015
Yu Zhang Pengli Zhu Gang Li Wenzhao Wang Liang Chen Daoqiang Daniel Lu Rong Sun Feng Zhou Chingping Wong

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 ...

2017
Abdullah Avşar Yener Gökbulut Burak Ay Selahattin Serin

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...

Journal: :Organic letters 2006
Bas W T Gruijters Maarten A C Broeren Floris L van Delft Rint P Sijbesma Pedro H H Hermkens Floris P J T Rutjes

[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...

Journal: :Angewandte Chemie 2008
Chandra M Rao Volla Pierre Vogel

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...

Journal: :iranian journal of science and technology (sciences) 2015
m. karimkoshteh

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...

Journal: :Catalysts 2023

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...

Journal: :Chemical communications 2010
Jinli Liu Chengkun Guo Zhaofu Zhang Tao Jiang Huizhen Liu Jinliang Song Honglei Fan Buxing Han

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.

Journal: :Chemical communications 2013
John-Michael Collinson James D E T Wilton-Ely Silvia Díez-González

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.

Journal: :Nature chemistry 2018
Matthew D Marcinkowski Matthew T Darby Jilei Liu Joshua M Wimble Felicia R Lucci Sungsik Lee Angelos Michaelides Maria Flytzani-Stephanopoulos Michail Stamatakis E Charles H Sykes

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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