Nickel source

It has been mentioned in an earlier chapter that nickel deposits are basically of two types sulfidic and lateritic (oxide). The scenario of nickel extraction from nickel sulfide concentrates and nickeliferrous pyrrho tite (these two are the two products of physical beneficiation of nickel sulfide ores), and from limonitics and gamieritics (these are the common lateritic ores) has been presented in Figure 5.6. It can be seen that nickel is extracted from its various sources by pyro, pyro-hydro and hydroprocessing. The account given here pertains to the latter two processes applied to the various nickel sources. 

Meanwhile, the olefinic geometry is completely controlled by selection of suitable ligands (PPh3 vs. heterocyclic carbene) and nickel sources (Scheme 86). 

Deposition of metals around the large Copper Cliff smelter in Sudbury, Ontario, is a significant local problem. It is estimated that 42% of nickel particulates emitted from the 381-m stack are deposited within a 60-km radius of the smelter (Taylor and Crowder 1983). The Copper Cliff smelter, one of three large nickel sources in the Sudbury area, emits 592 pounds (269 kg) of nickel a day. 

The catalysts comprise a chelating ligand such as diphenylphosphinobenzoic or-acetic acid combined with nickel sources like (j) -l,5-cyclooctadiene)2Ni (equation 18) or NiCl2/NaBH4. A nickel hydride species is presumed to be the active catalytic species. On an industrial scale, the reaction is run in a polar solvent such as 1,4-butanediol, in which the catalyst is soluble but the olefin products are insoluble. Addition of B(C6F5)3 to these systems converts them from neutral to zwitterionic see Zwitterion) with a large increase in activity (equation 19). ... 

Modified nickel catalysts were prepared from the various nickel sources (Table 1). In the case of the modified nickel catalysts prepared from NiO, e.d. ability of the catalyst depended on the NiO manufacturers. These phenomena were also observed for the e.d. hydrogenation of methyl acetoacetate (MAA) [6]. Since the method of the NiO preparation presumably affect the percentage of crystallite part of reduced Ni, the types of NiO would reflect the e.d. ability of the catalyst. On the other hand, fine nickel powder (FNiP) gave the e.d. catalyst... 

Osawa, T., Amaya, Y., Harada, T., and Takayasu, O. (2003) Enantio-differentiating hydrogenation of methyl acetoacetate over asymmetrically modified reduced nickel catalysts. The effect of the nickel sources on the enantio-differentiating ability, J. Mol.Catal A Chem. 211,93-96. 

The reactivity of aryl triflates [24,32,36,49] and other sulfonates [45,48] can be slightly different than is presented here, what depends on the catalyst and the reaction conditions used. For example, the SM reactions of aryl chlorides in the presence of aryl triflates catalysed by Pd2(dba)3 / 2Pt-Bu3 have given exclusively the biaryl derived from the chloride, whereas the use of Pd(OAc)2 / 2PCy3 catalytic system leads to predominant SM reaction of aryl triflate. The latter results indicate the fact, that the (phosphine) ligand(s), not the palladium (nickel) source, controls chloride / triflate selectivity, as well as other closely reactive substrates. 

The removal of nickel from nickel-containing alloys is an important factor determining the corrosion rate of these materials in several liquid metals. If a high nickel source is placed upstream in an isothermal zone, the nickel removal rate from an alloy sample downstream could be reduced, If several alloys with different nickel contents are included in the same test it would seem appropriate to arrange them in... 

Brunner and Hammer in 1984, who employed Co(acac)2 combined with a chiral C2-symmetric diamine ligand which provided enantioselectivities of up to 66% ee. Later in 1988, Soai et al developed the first asymmetric conjugate additions performed under chiral nickel(ii) catalysis/ The process, which involved dieth-ylzinc addition to chalcones, provided the corresponding 1,4-products in low to moderate enantioselectivities (<55% ee) by using an ephedrine derivative as the chiral ligand, as shown in Scheme 2.1 (first equation). Soon after, better enantioselectivities of up to 90% ee were achieved by the same authors using Ni(acac)2 as the nickel source instead of NiBr2, bipyridine as additive, and acetonitrile as solvent (Scheme 2.1, second equation). ... 

Nanosized ytterbium (Yb)-substituted n-Ni(OH)2 was S5mthesized by ultrasonic-assisted precipitation, using nickel sulfate as nickel source and Yb(N03)3 x 5H2O as doping material (118). 

In this context, there are several documented examples of discrepancies in reactivity. For example, the reactions of IPr and ItBu with various nickel sources have drastically different outcomes. The reaction of IPr with [Ni(COD)2] was reported to form [(IPr)2Ni] cleanly, whereas the reaction of ItBu produced several products, but not [(ItBu)2Ni]. ... 

The nickel-catalyzed cross-coupling of boronic acids with secondary phosphine oxides is an attractive approach for the preparation of arylphosphine oxides (Scheme 4.208) [346], After some experimentation, the authors found that nickel(II) bromide was the most effective nickel source. A mineral base was needed and potassium carbonate was effective. The substrate scope of this reaction was exceptionally high, and a range of functionalized boronic acids as well as secondary phosphine oxides were successfully cross-coupled. One drawback to this system was the use of 1,2-dichloroethane as the solvent for this reaction. It was noteworthy that the chemistry could be carried out under an atmosphere of air for some examples with only a minor reduction in the yields of the arylphosphine oxides. Thus, this reaction is very attractive as no glovebox or vacuum manifold was needed. This chemistry has the potential to generate a large number of different arylphosphine oxides due to the vast array of boronic acids that are readily available. 

Ni and Ge, which were ion-implanted into a nickel source, were coulomb-excited with 20— 30 MeV oxygen ions from a tandem van de Graaf generator. The Mossbauer effect was observed using nickel and germanium absorbers, respectively. ... 

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