Nickel removal as a function

Figure 2. Nickel removal as a function of pH for varying ionic strengths (lines are predicted by REDEQL2 using pK, = iS.2, pNij> = 4.77 ( J) I=10-3, o I = io-3 (a I = 10- )...

Figure 4. Nickel removal as a function of pH in the presence of oxide surfaces I = 0.01, FeOOH = 0.59 gjh (50 m /L),...

Fig. 8. The adsorption of hydrogen on copper-nickel catalysts as a function of the copper content. The circles represent the total amount of hydrogen adsorbed at room temperature at 10-cm pressure. The triangles represent the amount of strongly adsorbed hydrogen, i.e., the amount not removed by a 10-min evacuation at room temperature following the completion of the initial adsorption isotherm. The amount of strongly adsorbed hydrogen is determined as the difference between the initial isotherm and a subsequent isotherm obtained after a 10-min evacuation (74).

Concentration of powder in developer complex, mg/g Fig. XII.6. Specific charge on particles as a function of weight concentration of toner powder (curves 1-3) (1) SK-8 toner powder, copper carrier (2) same powder with nickel carrier (3) KSCh-4 toner powder, copper carrier. Curve 4 shows fraction of powder removed as a function of toner concentration. 

Fig. 3. The activity of Raney nickel for ethylene hydrogenation as a function of the aibount of hydrogen removed by pumping.

The behavior of 3 toward ether or amines on the one hand and toward phosphines, carbon monoxide, and COD on the other (Scheme 2), can be qualitatively explained on the basis of the HSAB concept4 (58). The decomposition of 3 by ethers or amines is then seen as the displacement of the halide anion as a weak hard base from its acid-base complex (3). On the other hand, CO, PR3, and olefins are soft bases and do not decompose (3) instead, complexation to the nickel atom occurs. The behavior of complexes 3 and 4 toward different kinds of electron donors explains in part why they are highly active as catalysts for the oligomerization of olefins in contrast to the dimeric ir-allylnickel halides (1) which show low catalytic activity. One of the functions of the Lewis acid is to remove charge from the nickel, thereby increasing the affinity of the nickel atom for soft donors such as CO, PR3, etc., and for substrate olefin molecules. A second possibility, an increase in reactivity of the nickel-carbon and nickel-hydrogen bonds toward complexed olefins, has as yet found no direct experimental support. 

The apparatus consists of a simple vacuum manifold similar to that shown in Fig. 4. The vacuum manifold should be fabricated from nickel or Monel metal, with silver-soldered or Swagelok connections. Valves should be of Monel metal, and the traps and scrubber, the function of which is to remove hydrogen fluoride vapor from the C103 F product, may be constructed conveniently of poly(chlorotrifluoroethylene) (Kel-F) tubing. A nickel cylinder of 500-ml. or 1-1. capacity serves as a reaction vessel, and a 500-ml. Monel bulb or similar vessel may be used as a product receiver. The scrubber (about 1-in. o.d.) is charged with pellets of sodium fluoride prepared in a separate operation by heating sodium... 

Isothiazoles are reductively desulfurized by Raney nickel, and this method has been used to confirm structures.3,51 In his remarkable synthesis of colchicine, Woodward employed the isothiazole nucleus as a template on which the various rings were constructed, and finally removed the sulfur with Raney nickel to leave a nitrogen function in the correct position [Eq. (22)].e7,68... 

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