Nickel oxide/hydroxide catalysts

The temperature required for the reduction of cobalt oxides to the metal appears to be somewhat higher than for the reduction of nickel oxide. The catalyst with a higher catalytic activity is obtained by reduction of cobalt hydroxide (or basic carbonate) than by reduction of the cobalt oxide obtained by calcination of cobalt nitrate, as compared in the decomposition of formic acid.91 Winans obtained good results by using a technical cobalt oxide activated by freshly calcined powdered calcium oxide in the hydrogenation of aniline at 280°C and an initial hydrogen pressure of 10 MPa (Section... 

The alkali free catalyst used in this study was a commercial nickel oxide/ -alumina steam reforming catalyst. The total nickel content of the catalyst was 10 % w/w. An alkali promoted catalyst was prepared by dipping the nickel oxide/< -alumina catalyst in a 12% v/v potassium hydroxide solution and then drying the catalyst, at lOD C, for a period of 16 hours The... 

Only about 6% of the produced nickel is applied for the production of nickel compounds. An important one is nickel hydroxide [Ni(OH)2], which is used for nickel-cadmium and nickel-iron batteries. For the production of catalysts the hydroxide, nitrate, sulfate, formate, and carbonate of Ni are used. In the pigment industry nickel oxide, hydroxide, and phosphate are applied and for electroplating nickel sulfate, sulfamate, and tetrafluoroborate are used. 

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). 

In this special field, earlier work had been done in other laboratories, such as by the Schering Company, Berlin (36), and by Ipatieff (37) in connection with his work on the hydrogenation of camphor and of other organic compounds. At both places, the favorable effect of alkali oxides and earth alkali oxides on nickel, cobalt and copper has been investigated. Similarly, Paal and his coworkers (38) have used a palladium-aluminum hydroxide catalyst in 1913 for the hydrogenation of double bonds. Bedford and Erdman (39) had reported that the catalytic action of nickel oxide is enhanced by the oxides of aluminum, zirconium, titanium, calcium, lanthanum, and magnesium. 

Hydrogenation of Styrene Oxide. Excellent yields of phenethyl alcohol are obtained when styrene oxide is hydrogenated at low temperature, using Raney nickel as a catalyst and a small amount of sodium hydroxide [140]. 

Nickel oxide, prepared by dehydration of nickel hydroxide under vacuum at 250°C. [NiO(250)]y presents a greater activity in the room-temperature oxidation of carbon monoxide than nickel oxide prepared according to the same procedure at 200° C. [NiO(200)]> although the electrical properties of both oxides are identical. The reaction mechanism was investigated by a microcalorimetric technique. On NiO(200) the slowest step of the mechanism is CO. i(ads) + CO(ads) + Ni3+ 2 C02(g) + Ni2+, whereas on NiO(250) the rate-determining step is O (0ds) + CO(ads) + Ni3+ - C02(g) + Ni2+. These reaction mechanisms on NiO(200) and NiO(250), which explain the differences in catalytic activity, are correlated with local surface defects whose nature and concentration vary with the nature of the catalyst. 

Several, different, electrochemical oxidations of 26 to 27 have been reported. Using a variety of electrodes (copper, Monel metal, nickel, or silver), 26 was oxidized in aqueous potassium hydroxide solution containing potassium chromate or potassium permanganate, to afford 27 in 70-85% yield.118,119 This electrochemical oxidation has been conducted in aqueous, alkaline solution in the presence of a surfactant, but with added metal catalyst, to give 27 in 85-95% yield.120 Alternatively, the oxidation has been performed by using an anode on which nickel oxide was deposited. This anode, in a solution of 26 at pH >9, with or without nickel salts, afforded 27 in >90% yield.121 A number of additional publications described122-140 other modifications of the... 

Nicklin, with others, filed several early patents describing the use of uranium oxides as steam reforming catalysts [69], U3O8 was used along with nickel oxide as the basis of a steam reforming catalyst, and it was modified with potassium species (potassium hydroxide, potassium oxide and/or potassium carbonate), all supported on either alumina or a mix of alumina and magnesium oxide. The uranium and nickel catalysts proved to be extremely efficient for steam reforming. 

Figure 6.5 shows the yields ([wt%]) of the reaction of PET using several transition metal oxide catalysts under the following conditions a temperature of 500°C, a time factor (the ratio of the mass of the catalyst W, to the PET feed rate F) of 0.317 h, and a particle size of 0.21-0.25 mm. Fc203 did not show activity, hence these results have been omitted. With respect to the reduction of terephthalic acid, FeOOH, nickel hydroxide and nickel oxide showed the decomposition activity of terephthahc acid. However, a large amount of benzoic acid, which is also a sublimate material (sublimation point 100°C), was produced over nickel hydroxide and nickel oxide. Because these nickel compounds are more expensive than FeOOH, FeOOH was considered to be a suitable catalyst for the decomposition of terephthalic acid. 

Summarizing all the information obtained above, the course of formation of the nickel catalyst supported on AI2O3 is pictured in Fig. 5. The dried nickel hydroxide decomposes into nickel oxide, a part of which combines with carrier alumina and forms nickel aluminate in the interface of the two solid phases. 

Hydrogenation Copper chromite (Lazier catalyst). Copper chromium oxide (Adkins catalyst). Lindlar catalyst (see also Lithium ethoxyacetylide, Malealdehyde, Nickel boride). Nickel catalysts. Palladium catalysts. Palladium hydroxide on carbon. Perchloric acid (promoter). Platinum catalysts. Raney catalysts, Rhenium catalysts. Rhodium catalysts. Stannous chloride. Tributylborane. Trifluoroicetic acid, Tris (triphenylphosphine)chlororhodium. 

---