Ni-based catalytic system

The Ni-based catalytic system was synthetically superior (100 °C for Ni instead of 140 °C for Pd) [123]. Five-membered and six-membered dichalcogenides... 

Gau et al. [352] recently used a simple Ni-based catalytic system to achieve highly efficient cross-coupling of various benzylic and aryl bromides to alkynylalanes with yields >90% in almost all cases. A more sophisticated Hgand system was used to afford the first enantioselective conjugate addition of an alkynylaluminum to... 

Some details of polymerization process are represented in Table 6. Addition poly(5-trimethylsilyl-2-norbomenes) were obtained with tiie yields up to 80%. All of them were completely soluble in aromatic solvents. Among the Ni-based catalytic systems presented in Table 6. 

Contemporary commercial homogeneous nickel based catalytic systems utilize high concentrations of olefin. We therefore investigated the Ni(sacsac)(PBu3)Cl derived system in toluene (1 255 w/w solvent). The solution was apparently homogeneous before activation, but formed a multiphase system after activation. 

Lu and Crabtree described a Ni-based catalytic model system that operates in the reverse direction, i.e., CO oxidation to The square-planar Ni complexes are dimeric in the... 

Alkynylations Catalyzed by Other Transition Metals While a number of transition metals, including Ag, Au, Co, In, Rh, Ru, and even rather scarce Sm, have occasionally been reported to possess a distinct catalytic activity in the Sonogashira cross-coupling [28, 147], industrially relevant, cheaper Cu, Ni, and Fe experienced by far the most scientific attention. In the 1990s, Miura et al. [9] have discovered that various aryl and vinyl iodides could be coupled with terminal alkynes in a Cu-catalyzed reaction at elevated temperatures in DMF or DMSO with added PPhj and base. This initial finding has sparked further research efforts toward more sophisticated Cu-based catalytic systems. 

Pd(PPh3)4. An analogous promoting effect of iodide anion on the oxidative addition of Mel to [Rh(CO)2l2] has been noted and the formation of [Rh(CO)2l3] proposed [115]. Based on this general reactivity, we propose that the effect of halide even in the Pd-phenanthroline and Ni-phosphine catalytic systems for the carbonylation of nitrobenzene discussed in this paragraph can be described by the following reaction scheme (Scheme 3) ... 

In this work, the catalytic reforming of CH4 by CO2 over Ni based catalysts was investigated to develop a high performance anode catalyst for application in an internal reforming SOFC system. The prepared catalysts were characterized by N2 physisorption, X-ray diffraction (XRD) and temperature programmed reduction (TPR). 

The most active catalysts for NH3 decomposition are based on Ru, however, cheaper Fe, Co, Ni and alloy systems are also intensely investigated [148]. The impact of the support material is remarkable. In a study by Au et al., Ru/CNTs performed better than all oxide-supported systems, whereas activated carbon resulted in one of the lowest NH3 conversions (Tab. 15.6) [147]. The dispersion of the active component as well as basicity [147] and conductivity [149] of the support are discussed as the relevant factors for high catalytic efficiency. However, the difference between CNT and activated carbon support is still remarkable. Thus it is not surprising that even the residual catalyst material on commercial MWCNTs, which is basically based on Fe and Co, results is a high catalytic performance in NH3 decomposition [150]. 

The most often-reported metallic systems used in the formation of carboxylic acids are most certainly those systems that involve a zero-valent nickel species as the active intermediate. Ochiai et al. reported on a bimetallic catalytic system which allowed the synthesis of various saturated carboxylic acid in good yields, under very mild conditions [53] (0.1 MPa C02, 4—8 h reaction time, temperatures ranging from room temperature to 323 K). The catalytic system was based on the use of organozinc reagents as carbon nucleophiles, which could be selectively carboxy-lated in the presence of Ni(acac)2 as the main catalyst. 

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