Carbon over nickel

Nickel tetracarbonyl Ni(CO)4 was the first metal carbonyl to be discovered, by Mond in 1890 it is obtained by passage of carbon monoxide over nickel metal heated to 320 K. It is a volatile, toxic liquid (b.p. 315 K), and has a tetrahedral structure. It has considerable stability, but inflames in air it is believed that in the structure... 

Goal Upgrading via Fischer-Tropsch. The synthesis of methane by the catalytic reduction of carbon monoxide and hydrogen over nickel and cobalt catalysts at atmospheric pressure was reported in 1902 (11). 

Ma.nufa.cture. Nickel carbonyl can be prepared by the direct combination of carbon monoxide and metallic nickel (77). The presence of sulfur, the surface area, and the surface activity of the nickel affect the formation of nickel carbonyl (78). The thermodynamics of formation and reaction are documented (79). Two commercial processes are used for large-scale production (80). An atmospheric method, whereby carbon monoxide is passed over nickel sulfide and freshly reduced nickel metal, is used in the United Kingdom to produce pure nickel carbonyl (81). The second method, used in Canada, involves high pressure CO in the formation of iron and nickel carbonyls the two are separated by distillation (81). Very high pressure CO is required for the formation of cobalt carbonyl and a method has been described where the mixed carbonyls are scmbbed with ammonia or an amine and the cobalt is extracted as the ammine carbonyl (82). A discontinued commercial process in the United States involved the reaction of carbon monoxide with nickel sulfate solution. 

In Micro Dumas combustion (CHN analysis) the sample is vaporised and carried by a stream of CO2 over nickel oxide at 1000 °C to oxidise the sample to CO2, H2O and N2. Nickel reduces nitrogen oxides in the heated combustion tube. Carbon monoxide, formed by reduction of CO2 by nickel, is oxidised by passage through hopcalite at 110°C. Traces of... 

Catalytic Dehydrogenation of Organic Chemical Hydrides over Carbon-Supported Nickel-Based Nanoparticles under Superheated Liquid-Film Conditions... 

If a denotes C—C bond rupture in the vicinity of the substituent and b that in the next position, bja values are usually higher than unity for the four metals mentioned. This is the situation, for example, with C5 ring opening over carbon-supported 98) and unsupported (62) platinum, as well as rhodium, iridium, and palladium 42). Ring opening over nickel is also selective 42,99) much less (or even the opposite) selectivity has been found with other metals 42). 

Cyclohexane dehydrogenates rather rapidly to benzene. Its rearrangement has not been reported over pure metals until now. Cg Ring opening is negligible over platinum and palladium 48, 5i) slight hexane formation was reported over carbon supported rhodium, iridium, and, especially, osmium and ruthenium (702), as well as over nickel on alumina (99). 

Methanol carbonylation over nickel- activated carbon was shown to be a structure-insensitive reaction. 

Microwave heating was also used to induce catalytic oligomerization of methane to afford C2-C4 hydrocarbons.571 Changing the catalysts and the applied power and the use of diluent gas (He) allowed significant alteration of product selectivities. Selectivity to benzene over nickel powder or activated carbon was 24 and 33%, respectively. 

One of the characteristic features of the metal-catalysed reaction of acetylene with hydrogen is that, in addition to ethylene and ethane, hydrocarbons containing more than two carbon atoms are frequently observed in appreciable yields. The hydropolymerisation of acetylene over nickel—pumice catalysts was investigated in some detail by Sheridan [169] who found that, between 200 and 250°C, extensive polymerisation to yield predominantly C4 - and C6 -polymers occurred, although small amounts of all polymers up to Cn, where n > 31, were also observed. It was also shown that the polymeric products were aliphatic hydrocarbons, although subsequent studies with nickel—alumina [176] revealed that, whilst the main products were aliphatic hydrocarbons, small amounts of cyclohexene, cyclohexane and aromatic hydrocarbons were also formed. The extent of polymerisation appears to be greater with the first row metals, iron, cobalt, nickel and copper, where up to 60% of the acetylene may polymerise, than with the second and third row noble Group VIII metals. With alumina-supported noble metals, the polymerisation prod-... 

Indications of the mechanism of isomerization of saturated hydrocarbons were obtained by Ciapetta (C3), who observed that olefins were isomerized over nickel-silica-alumina catalyst at appreciably lower temperatures than were the corresponding saturated hydrocarbons, suggesting that olefins were intermediates in the reaction. Ciapetta also suggested that the rearrangement of the carbon skeleton took place via a carbonium... 

Fig. 4. Activation energy of carbon monoxide oxidation over nickel oxide of different layer thickness on silver (26). (Copyright by Akademische Verlags-Gessellschaft. Reprinted with permission.)...

J. Rostrup-Nielsen, Equilibria of decomposition reactions of carbon monooxide and methane over nickel catalyst, J. Catalysis, 27 343 (1972)... 

The dependence of the action of an additive upon temperature is well illustrated (Fig. 11) by the data of Element (96), who studied the catalytic oxidation of carbon monoxide over nickel oxide promoted with barium... 

For depressing the overhydrogenation of aromatic aldehydes and ketones over nickel or copper-chromium oxide at elevated temperatures and pressures, the presence of an aqueous alkali metal carbonate or hydroxide is effective.44 Thus, 60 g of benzaldehyde was hydrogenated over 1.5 g of a supported nickel in the presence of 2 ml of 10% aqueous sodium carbonate at 90-115°C and 3.2 MPa H2 to give 91.5% of benzyl alcohol and 7.7% of toluene, compared to 48.7 and 49.5%, respectively, without aqueous sodium carbonate. 

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