Preparation of Ni

A nickel slurry was prepared in the usual manner and allowed to settle. The pale beige solution above the slurry was removed, and 1 equiv of CeFsl was syringed in. The mixture was stirred at about 60°C for 19 h, after which time a deep orange-brown solution existed. The solution was allowed to cool, and 3 equiv of (C6H5)2PH was slowly syringed in. Initially the mixture became yellow and then deep green in a mildly exothermic reaction. The mixture was stirred 

This was dissolved in CH2CI2. Slow solvent evaporation from the golden yellow solution resulted in yellow crystals in 38% yield. Recrystallization from toluene affords the compound containing a toluene of crystallization mp 161-162°C crystals are completely black before melting IR (Nujol) P-H 2360cm  

2 Preparation of 3-Aryl-2-hydroxy-1 -propane by Nickel-Mediated Addition of Benzylic Halides to 

Acyloins (la) [29,30] and bis-silylated derivatives of their enediols (lb) [31] have been demonstrated to be useful acyl anion equivalents (RCO ) and have been employed in an indirect but facile way for the preparation of ketones (3) (Equation 7.1). The hydroxy ketones (2), which are the key intermediates in this method, have been prepared by the reaction of acyloins (la) with organic halides in the presence of sodium hydroxide in dimethyl sulfoxide [29, 30] according to the Hein s procedure [32] or using sodium hydride in 1,2-dimethoxyethane (DME) (glyme) [33]. They also have been prepared by the alkylation of lithium enedi-olates of acyloins prepared from the corresponding lb and methyllithium [31]. These reactions proceed with C-alkylation however, the reaction conditions employed are quite basic which would limit substrate choice. 

We reported that smooth oxidative addition of organic halides such as aryl, benzyl, and allyl halides to metallic nickel proceeded to afford organonickel halides under mild conditions, which yielded homocoupled products [11, 41] or ketones by the reaction with acid chlorides [42] or alkyl oxalyl chlorides [43]. We describe here a new method for the preparation of 3-aryl-2-hydroxy-l-propanones (4) in good yield by the Grignard-type addition of benzyl halides to 1,2-diketones mediated by metallic nickel under neutral conditions [44]. 

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Boron trichloride, reaction with 2-aminobiphenyl, 46, 66 Boron trifluoride, in preparation of ni-tronium tetrafluoroborate, 47, 56 with hydrogen fluoride in isomerization of /-cymene to tM-cymene, 47, 41... 

Nigo et al. claim to have prepared Ni(Et2 /c)2Br2 106), whereas Jensen reports the preparation of Ni(Et2spectral data, we believe these products to be Ni(Et2 itc)3Br and Ni(Et2 xc)3Br 100), respectively, contaminated with NiBr2-... 

A preparation of Ni(II) on charcoal can also be used as the catalyst. It serves as a reservoir of active Ni(0) formed by reduction by the Grignard reagent.269... 

Bis( 73-allyl)nickel(0) and bis( 75-pentadienyl)iron(II) have been used as starting materials in the preparation of [Ni(PF3)4] and [Ni(PF2H)4], 0 The electronic structure of the fluorophosphine com-... 

An example of this type of reaction is that involving the preparation of Ni(r/3-C3H5)2. This reaction can be shown as... 

Sodium amalgam and elemental lithium have also been used as reducing agents in the preparation of [Ni(PPh3)2(CH2CCH2)]65 and [Ni(PPh3)2(PhCHCHPh)].154... 

Preparations of Ni[P(C6H5)3]3 and trarw-chloro(aryl)bis(triphenyl-phosphine)nickel from NiCl2[P(C6H5)3]2 (12) are reported. Alternatively, the trar s-chloro( aryl) bis (organophosphine) nickel complexes were prepared from Ni(PR3)3 (8, 13). Identical results were obtained from catalysts prepared in different ways. Because all the reactions involved in this work are sensitive to oxygen, all were carried out under N2. 

Other N-donors. The preparations of Ni(N2H4)2X2,nH20 (X = F or Br) have been... 

Both systems are suitable to check whether or not there is a directly proportional relationship between the width of the homogeneity range of a compound and the growth rate of its layer, predicted by the diffusional theory.5 It is clear that in view of the presence of the liquid zinc phase during preparation of Ni-Zn and Co-Zn reaction couples, all the inter-metallic phases had equal and favourable conditions to form their nuclei at the interface between nickel or cobalt and zinc, which could then readily grow during subsequent isothermal annealing. 

Case Study Preparation of Ni Bifunctional Catalysts Supported on Homoionic Na, K, Ca, and Mg Clinoptilolite... 

Alkilidine tantalum complexes have also been utilized for the preparation of ni-trido Tav. Reaction of ammonia with 31 or 32 afforded nitride 33 in moderate yields [14]. The structure of 33 has been determined by single-crystal X-ray crystallography and shown to consist of a pentameric complex, as depicted in Eq. (9). All of the Ta-N bond lengths are equivalent (2.00 A), suggesting a structure with extensive delocalization of the multiple bonds. 

A pH titration of the suspension solutions of NaBir or NiBir in Ni(N03)2 solution was carried out similarly as that for preparation of Ni(OH)2-montmorillonite mixed layered compound described by Yamanaka et al. [15], Separate NaBir and NiBir (dried at 80°C) were dispersed in Ni(N03)2 solution (O.IM), and agitated by ultrasonic vibration for 30 min. Then these suspensions were potentionmetrically titrated with a NaOH solution. The pH value at each stage of the titration was measured by a HORIBA F-22 pH meter. The titrated suspension was stirring for 10 min before the pH measurement at each stage of the titration before pH=8, 5 min before pH= 10, and 2 min to the end. A pure water and one with dispersed NiBir as well as a pure Ni(N03)2 solution were also similarly titrated for comparison. 

T. Nishikawa, T. Ono, N. Kakutani, M. Yano, and Y. Ogo, Preparation of Ni Membrane Catalyst Supported on Ceramic Filter by CVD Method, Member of Faculty of Engineering, Osaka City University,... 

The first compound to be synthesized containing carbon monoxide as a ligand was another platinum chloride complex, reported in 1867. In 1890, Mond reported the preparation of Ni(CO)4, a compound that became commercially useful for the purification of nickel. Other metal CO (carbonyl) complexes were soon obtained. 

A simple procedure for the preparation of Ni/Si02 catalysts involves the precipitation of nickel dimethylglyoxime from a suspension of silica in an aqueous solution of a nickel salt.38,39 Calcination is not required since the resulting supported precipitate is easily reduced in a stream of hydrogen at 200°-250°C, giving very highly dispersed supported nickel catalysts. 

Two different routes were used for the preparation of Ni/Si02 catalysts. The starting material was always Ni(N03)2 but following the wet impregnation the metal hydroxide is the precursor. 

In the preparation of Ni/Hp catalysts by the deposition-precipitation method (DP), nickel hydrosilicates are formed mainly but not exclusively in the external surface of the Hp zeolite. The strong metal-support interaction induced by the DP preparation method prevents the Ni metal particles from sintering during the activation of the catalysts (calcination and reduction) and a homogeneous distribution of small nickel particles is obtained. The catalyst prepared by DP showed better catalytic activity in the hydrogenation of naphthalene than the catalyst prepared by cationic competitive exchange. 

The present work is part of a research program aimed at a systematic investigation of the different parameters controlling the preparation of Ni-Co molybdate propane ODH catalysts. The goal of this paper is to study the influence of the co-precipitation pH conditions on the nature of the active phase and the activity properties of unsupported Ni-Co-Molybdate catalyst. 

The preparation of [Ni(PMe3)4]+ by the addition of PMe3 to [NiXMe-(PMe3)2] (X = halide) (215) is particularly noteworthy in suggesting that the reductive elimination of alkyl or aryl halides from Ni(II) phosphine complexes via 17-electron intermediates may be important in catalytic cycles... 

From the preparation of Ni supported CaSiOs using the solution of Ni cation, the surface Ca ions of CaSi03 were easily exchanged to Ni ions in the solution. Due to this property, two kinds of Ni supported CaSiOs catalyst can be prepared by changing the preparation method one is Ni and Ca ion co-supported CaSiOs prepared by the impregnation method, and the other is highly dispersed Ni supported CaSiOs catalyst compared with Ni supported over SiOz. 

Origin of the dispersion limit in the preparation of Ni(Co)Mo/Al203 and Ni(Co)Mo/Ti02 HDS oxidic precursors... 

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