Nickel precipitation catalysts

Nickel precipitation catalysts. Fischer and Meyer (11) carried out exhaustive research work trying to develop active Ni catalysts for the synthesis of higher hydrocarbons. In spite of the failure of all previous attempts, Fischer and Meyer found two types of nickel catalysts with a behavior similar to that of the best cobalt catalysts. 

Nickel sulfide, NiS, can be prepared by the fusion of nickel powder with molten sulfur or by precipitation usiag hydrogen sulfide treatment of a buffered solution of a nickel(II) salt. The behavior of nickel sulfides ia the pure state and ia mixtures with other sulfides is of iaterest ia the recovery of nickel from ores, ia the high temperature sulfide corrosion of nickel alloys, and ia the behavior of nickel-containing catalysts. 

General. The flame-sprayed Raney nickel catalyst was used in exexperiments HGR-10, HGR-12, and HGR-14, the pelleted precipitated catalyst in experiment HGR-13. Reactor conditions as a function of... 

Flame-Sprayed Raney Nickel Plates vs. Pellets of Precipitated Catalyst in a Packed Bed. Experiments HGR-13 and HGR-14 demonstrated that the performance of the plates sprayed with Raney nickel catalyst was significantly better than that of the precipitated nickel catalyst pellets. The sprayed plates yielded higher production of methane per pound of catalyst, longer catalyst life or lower rate of deactivation, lower CO concentration in the product gas, and lower pressure drop across the catalyst bed. 

Without microencapsulation, precipitation of both catalysts rendered them inactive (Scheme 5.5). Moreover, the addition of the second nickel-based catalyst (Cat. 2)... 

Nickel precipitated from aqueous solutions of nickel chloride by aluminum or zinc dust is referred to as Urushibara catalyst and resembles Raney nickel in its activity [48. ... 

The activity of the nickel catalyst is affected by major variations in carbon monoxide partial pressure. With very low carbon monoxide partial pressure, nickel precipitates as a metal powder and occasionally as nickel iodide. Stability of the catalyst is improved with higher CO partial pressure up to a point above which the catalyst activity drops linearly. The optimum level of carbon monoxide is different from one catalyst mixture to another. This behavior is characteristic of all the nickel catalyzed carbonylation reactions we studied. In the Li-P system, optimum carbon monoxide partial pressure is in the range of 700 to 800 psi (Table V). On the other hand, the optimum carbon monoxide partial pressure for the Li-Sn system is in the range of 220 to 250 psi, at 160 C, and 450 psi at 180 C (Table VI). It is presumed that the retarding effect of higher carbon monoxide partial pressure is associated with stabilizing an inactive carbonyl species. 

Fig. 10. Amount of Nickel convertible to Ni(CO)4 in relation to Fco/Fh ratio for co-precipitation catalysts.

Kruissink, E.C., Van Reijen, L.L. and Ross, J.R.H. (1981) Coprecipitated nickel—alumina catalysts for mefhanation at high temperature. Part 1. Chemical composition and structure of the precipitates. J. Chem. Soc., Faraday Trans. 1, 77, 649. 

In a 100-ml crimped vial, t-butyl 5-norbomene-2-carboxylate (17.5 mmol) and the Step 1 product (7.5 mmol) were dissolved in 40 ml of toluene and then sparged with nitrogen for 30 minutes. The mixture was next treated with the slow addition of freshly prepared bis(toluene)bis(perfluoro-phenyl) nickel (II) catalyst (0.5 mmol) in 10 ml of dry toluene and stirred overnight. The polymer was precipitated into hexane and filtered, and 3.5 g of white powder were isolated. 

Sometimes, due to a low melting point of a salt, e.g., when a nitrate is chosen as the precursor of the active phase, homogeneous distribution is difficult to obtain. Then, the deposition precipitation method might be appreciated [91-93]. This method is illustrated for the synthesis of a nickel monolithic catalyst. 

An obvious improvement in the steam gasification of biomass for synthesis gas production is to operate at higher temperatures and to use catalysts to gasify as much of the char and liquid products as possible. Laboratory-scale experiments have been carried out to examine this possibility (Mitchell et al, 1980). Nickel precipitated on silica alumina (1 1) and a mixture of silica alumina and nickel on alumina were evaluated as catalysts for steam gasification at 750°C and 850°C and atmospheric pressure. The results are summarized in Table 9.6. The function of the silica alumina is to crack the hydrocarbon... 

We shall consider first the nature of the carbonaceous species produced by propane decompoeition on the nickel/ -alumina catalyst. From TEM, this was found to be filamental in nature. The mechanism of the growth of these filaments is proposed to involve diffusion of carbon through a metal particle and eventual precipitation at the rear of the metal crystallite (Kef 3,A). 

Metal-support interaction was observed in two nickel-silica catalysts, but they were prepared either by precipitating a complex carbonate from nickel nitrate solution containing Si02 as a slurry or co-precipitating the carbonate from a solution of nickel nitrate and sodium silicate. The similar spectra from the unreduced catalysts resembled in shape and binding energy a NiSi03 standard and were quite distinct from NiO. The interaction was... 

The first type was a nickel-thorium-kieselguhr precipitation catalyst and the second type a nickel-manganese-aluminum-kieselguhr precipitation catalyst. 

Cobalt precipitation catalysts. The development of cobalt catalysts (Fischer and Koch, 12) was similar to the development of the corresponding nickel catalysts. In the case of cobalt, however, it was easier to prevent extensive methane formation. The lOOCo 18Th02 100 kieselguhr catalyst became the so-called standard cobalt catalyst. 

Trambouze (39) et al. carried out investigations on the activity of nickel catalysts. Teichner and Pernoux (40) found that the efficiency of kieselguhr important for Fischer precipitation catalysts is proportional to the quantity of reactive silica. Examinations with electron microscope... 

The precipitate of nickel obtained on adding zinc dust to a solution of nickel chloride can be activated by treatment with aqueous ammonia (Urushibara Ni—NH3). This nickel catalyst contains appreciable amounts of residual ammonia and is suitable for reduction of nitriles to amines. Treating the nickel precipitate with sodium hydroxide solution gives the Urushibara Ni—B catalyst Urushibara Co—B catalyst is obtained analogously from cobalt chloride.180... 

Nickel-kieselguhr catalysts with or without a small percentage of magnesia and thoria These catalysts were prepared by precipitation of the metals as carbonates from the solutions of their nitrates holding a suspension of B.D.H. kieselguhr. The carbonates were subsequently decomposed to the oxides in a current of air and the nickel reduced by hydrogen at 300°. 

A. Nickel-Kieselguhr Catalyst It was prepared by precipitating nickel carbonate from a hot solution of nickel nitrate by hot potassium carbonate solution in presence of kieselguhr, washing and drying the mass, and reducing it in situ in the reaction bomb itself by a stream of hydrogen at 300-350°. 

The nickel molybdate catalyst used in this study, prepared by the precipitation method described by Mazzocchia [4], has been supplied by Elf Atochem (France). The bulk Mo / Ni ratio in this solid is practically equal to 1 it can exist as phases a and P, differing by the coordination of Ni ions. Only the results for the a form will be reported here. The specific surface area as measured by N2 adsorption is about 40 m / g. 

The samples of nickel-alumina catalysts were analyzed for nickel by solution of the sample in sulfuric acid, and neutralization with ammonium hydroxide in the presence of tartaric acid, and were then slightly acidifled with dilute sulfuric acid. Nickel was precipitated with dimethyl-glyoxime. It should be pointed out that any attempt to analyze for... 

The mechanism of steam reforming of methane over a nickel catalyst (equation 168) or over different nickel alumina catalysts has been investigated at 873K k The rate of reaction on a commercial co-precipitated catalyst A (poorly crystallized y-Al203 containing 75% Ni) is given by equation 169 ... 

Lippens, B. C., Fransen, P., van Ommen, J. G., Wijingaarden, R., Bosch, H., and Ross, J. R. H. 1985. The preparation and properties of lanthanum-promoted nickel-alumina catalysts structure of the precipitates. Solid State Ionics 16 275-82. 

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