نتایج جستجو برای: nickel catalyst

تعداد نتایج: 76389  

2017
Nicholas A. Weires Daniel D. Caspi Neil K. Garg

Nickel-catalyzed coupling reactions provide exciting tools in chemical synthesis. However, most methodologies in this area require high catalyst loadings, which commonly range from 10-20 mol % nickel. Through an academic-industrial collaboration, we demonstrate that kinetic modeling can be used strategically to overcome this problem, specifically within the context of the Ni-catalyzed conversio...

2017
Yi-Mei Xu Kuan Li Yuhong Wang Wei Deng Marinos Pitsikalis

The nickel(II) catalyst has manifested higher catalytic activity compared to that of other late transition metal catalysts for norbornene polymerization. Therefore, several structurally similar trans-nickel(II) compounds of N,O-chelate bidentate ligands were synthesized and characterized. Both the electronic effect and the steric hindrance influence polymerization. The molecular structures of 2...

The role of nickel as catalyst on the conversion of methane and ethylene in a gas phase flow reactor in the absence of oxygen is studied. In this study, nickel in its different forms is used as catalyst. The role of pressure, flow rate, and temperature on the conversion of feed gases is investigated. The experiments have been carried out in the presence and absence of the catalysts to measure t...

Journal: :Chemical communications 2011
Ning Liu Li Wang Zhong-Xia Wang

P,N,O-chelate nickel complexes efficiently catalyse the cross-coupling reaction of aryl chlorides with arylzinc reagents in a 1:1 THF-NMP mixture. The reactions proceed at room temperature with low catalyst loading.

Journal: :Chemical communications 2009
Jun Terao Fumiaki Bando Nobuaki Kambe

A new method for the regioselective three-component cross-coupling of alkyl halides, alkynes, or enynes with organomagnesium or organozinc reagents in the presence of a nickel catalyst and a dppb ligand has been developed.

Journal: :Chemical communications 2014
Renxi Jin Yang Yang Yunfeng Li Lin Fang Yan Xing Shuyan Song

Highly dispersive and ultrafine Au nanoparticles were effectively immobilized on the surface of hierarchical double-walled nickel silicate hollow nanofibers assembled by ultrathin nanosheets, which showed remarkable catalytic performances as an efficient and reusable hydrogenation catalyst.

An alumina-supported nickel catalyst was prepared by impregnation of Ni2+ solution onto mesoporous alumina under microwave irradiation (denoted as M-Ni/Al2O3). For comparison, a catalyst with the same nickel content was prepared by conventional impregnation method (denoted as UM-Ni/Al2O3). Both M-Ni/Al2O3 and UM-Ni/Al2O3 catalysts were applied to the syngas (H2 + CO) production by methane oxy-s...

Journal: :Chemical communications 2015
Eva Koch Ryosuke Takise Armido Studer Junichiro Yamaguchi Kenichiro Itami

A nickel-catalyzed α-arylation of esters and amides with phenol derivatives has been accomplished. In the presence of our unique nickel catalyst, prepared in situ from Ni(cod)2, 3,4-bis(dicyclohexylphosphino)thiophene (dcypt), and K3PO4, various esters and amides undergo α-arylation with O-arylpivalates or O-arylcarbamates to afford the corresponding coupling products. The thus obtained α-aryl ...

Journal: :Journal of the American Chemical Society 2015
Sumit Chakraborty Paige E Piszel Cassandra E Hayes R Tom Baker William D Jones

A highly selective (>99%) tandem catalytic system for the conversion of ethanol (up to 37%) to n-butanol, through the Guerbet process, has been developed using a bifunctional iridium catalyst coupled with bulky nickel or copper hydroxides. These sterically crowded nickel and copper hydroxides catalyze the key aldol coupling reaction of acetaldehyde to exclusively yield the C4 coupling product, ...

Journal: :Organic letters 2016
Felicia Weber Monika Ballmann Corinna Kohlmeyer Gerhard Hilt

The transposition of a homoallyl pinacol boronic ester was realized by a highly reactive nickel-catalyst system comprising NiCl2(dppp), zinc powder, ZnI2, and Ph2PH. The in situ generated Z-crotyl pinacol boronic esters were reacted with various aldehydes to form syn-homoallylic alcohols in high diastereoselectivities. The present nickel-catalyzed reaction is complementary to the iridium-cataly...

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