Yield nickel

In the carbonyl process, the Hquid is purified, vaporized, and rapidly heated to ca 300°C which results in the decomposition of the vapor to carbon monoxide and a fine high purity nickel powder of particle sizes <10 fim. This product is useflil for powder metallurgical appHcations (see Metallurgy, powder). Nickel carbonyl can also be decomposed in the presence of nickel powder, upon which the nickel is deposited. This process yields nickel pellets, typically about 0.8 cm dia and of >99.9 wt% purity. 

With nickel/alumina catalysts (cf. 4 ) preparation by coprecipitation or by the decomposition of a high dispersion of nickel hydroxide on fresh alumina hydrogel, yields nickel aluminate exclusively. On the other hand, when, as in impregnation, larger particles of nickel compound are deposited, the calcination product is a mixture of nickel oxide and nickel aluminate. The proportion of nickel oxide increases when occlusion of the impregnation solution leads to a very nonuniform distribution (49). 

The DA reactions with o-benzoquinodimethane have also been extended to nickel(II) N-confused porphyrin 14 to yield nickel(II) A-confused isoquinoporphyrin 15 (... 

Ligand (119) yields nickel complexes of type [Ni2L](BF4)4 (low spin) and [Ni2L(NCS)4].2H20 (high spin). For each of these complexes, physical studies indicate that the macrocycle circumscribes the two nickel ions such that each ion is surrounded by four sulfur donors in a planar array. 

Nickel is stable in caustic alkahes. At moderate temperatures, it decomposes gaseous ammonia into hydrogen and nitrogen. Nickel combines with sulfur, phosphorus, carbon, arsenic, antimony, and aluminum at elevated temperatures. Fusion of nickel powder with molten sulfur yields nickel sulfide, NiS. Reaction with aluminum can be explosive at 1,300°C, forming nickel-aluminum intermetallic products of varying compositions. 

Nickel has typical metallic properties it can be readily rolled, drawn into wire, forged, and polished. It is also ferromagnetic and a good conductor of both heat and electricity. Nickel is positioned after hydrogen in the electrochemical series and slowly displaces hydrogen ions from dilute hydrochloric and sulfuric acids. It reacts more rapidly with nitric acid. Nickel is highly resistant to attack by strong alkalis (Hawley 1981). Black nickel oxide readily yields nickel salts... 

Reduction reactions of nickel(If) compounds. The reduction of nickel(II) compounds to yield nickel(0) phosphine complexes has been carried out using a variety of reducing agents such as sodium amalgam, sodium sand, sodium borohydride, sodium naphthalenide and aluminum trialkyls. In some cases the phosphine ligand itself was found to act as the reducing agent. 

In this section we will briefly report some examples of oxidative addition reactions to nickel(0) compounds which yield nickel(I) and nickel(II) compounds. 

Figure 6-18. The condensation of the [Ni(en)3]2+ salts with acetone yields nickel(n) complexes of a new tetraaza macrocyclic ligand.

Hofmann and Hiendlmaier, Her., 1906, 39, 3184. Nickel under similar conditions yields nickelous nickelite, NiO.Ni08.2HaO. 

Organic salts of nickel do not themselves act catalytically, but are reduced by hydrogen when suspended in the heated oils, yielding nickel in various stages of oxidation, and these products effect the hydirogena-tion. Thus nickel formate is reduced by hydrogen at 210° C. in the presence of the oil to nickel suboxide, whilst at 250° C. complete reduction to the metal is effected. 

Nickel hydroxide dissolves in ordinary distilled water to the extent of 12-7 mgs. of Ni(OH)2 per litre at 20° C.10 It is soluble in acids, yielding nickel salts when heated, water is evolved, leaving a residue... 

Nickel Sesquitelluride, Ni2Te3, occurs in nature as the mineral melonite. It may be prepared by the addition of sodium telluride solution to one of nickel acetate acidulated with acetic acid.7 The resulting black precipitate has the composition Ni2Te3.4H20, and when heated in hydrogen yields Nickel Monotelluride, NiTe. 

Different studies have been conducted in order to verify the ability of nickelocene to yield nickel films with satisfactory properties. The main conclusion that has been drawn from these efforts is that, as is generally the case for many precursors using cyclopentadienyl ligands, nickelocene leads to carbon incorporation in the deposits. For this reason mainly, nickelocene has not been extensively used for deposition of nickel thin films by MOCVD. However, a literature review reveals that the question of carbon incorporation in nickel films processed from nickelocene has not... 

In contrast to the purely thermal cycloaddition which occurs in a nonstereospecific manner with respect to alkenes in low yield, nickel(0) catalysis results in a highly stereospecific cycloaddition, as demonstrated by the reactions between (11 equation 4) and dimethyl fumarate or dimethyl maleate. 

Reaction with CO at —60° C. yielded nickel carbonyl and a Ci3 ketone. Addition of one mole of P(C2H5)3 formed a crystalline complex which was identical with the compound obtained from cyclododecatriene-centro-nickel and... 

Conjugated dienes and C02 react with Ni(0) complexes to yield nickel allylcarboxylates.49 (Butadiene)Fe(PMe3)3 reacted with C02 to provide an allylcarboxylate metallacycle.50 The anionic (butadiene)Mn(CO)3 reacted readily with C02 to give the anionic allylcarboxylate.51 Similarly, 1,2-dienes reacted with C02 on some Ni(0) complexes.52... 

A suspension of the reagent oxidizes aniline at 80° to azobenzene in 80% yield and it oxidizes benzylamine at 60° to benzonitrile in 78% yield. Nickel peroxide oxidatively cleaves a-glycols and a-hydroxy acids in aprotic solvents (benzene, ether)." In an aqueous alkaline solution a-ketols and a-keto acids are cleaved to carboxylic acids. The reagent thus resembles lead tetraacetate. 

Similarly to the zirconocene/MAO catalysts, the activity of the Idemitsu catalyst systems is poor when the whole catalyst system (catalyst-i-co-catalyst) is taken into account. In the very best example (in terms of catalyst activity and polymer yield) nickel bis (acetylacetonate) was used in combination with MAO (molar ratio 1 200) to homopolymerize norbornene in toluene at 50 °C for 4 h affording a 70% conversion into high molecular weight (M 2.2x10 ), toluene-soluble poly-(norbornene). The ratio of norbornene to nickel was 20000 1 and the ratio of norbornene to aluminum was only 100 1. Thus, while the yield of polymer is high based on the nickel catalyst (25 700 g per g nickel), the yield based on aluminum is very poor (260 g per g aluminum or about 120 g per g MAO). It can readily be estimated that the cost of the MAO activator alone would add significantly to the cost of the polymer, as well as requiring costly removal of catalyst residues from the polymer. 

Oxidation to fuchsones.31 Attenburrow MnOz was used for oxidation of 3,5-disubstituted-4-hydroxytriphenylmethanes to 3,5-disubstituted fuchsones in high yield. Nickel peroxide and lead dioxide were equally satisfactory. The 3,5-disubstitution appears to be a requisite for smooth oxidation. 

USE On ignition yields "nickel yellow —a pigment used in oil and water colors. 

---