Reduced Nickel

Hydrazine/Raney nickel reduces 117/-dibenz.o[c,/][l,2,5Jtriazcpine to the dihydro derivative 1, a highly unstable compound, which readily reverts to the dibenzotriazepine in air.325... 

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... 

A U.S. Environmental Protection Agency (U.S. EPA) study of 165 sludges showed nickel concentrations ranging from 2 to 3520mg/kg (dry basis).18 Nickel toxicity may develop in plants from application of municipal wastewater biosolids on acid soils. Nickel reduces yields for a variety of crops including oats, mustard, turnips, and cabbage. 

For the catalytic reduction of aldehydes, nickel reduced at as low a temperature as possible is most efficient a quantitative yield of alcohol from acetaldehyde is obtained at 140°, while the optimum temperature for reducing formaldehyde is 90° and for propaldehyde 102°—14<0°. 

The distance between the current curves of two metals may sometimes be controlled by temperature as the value of the overvoltage varies under its effect. The depositi m potentials of nickel and zinc on electrolysis of their salts in aqueous ammonia solution at 20 °C differ only slightly because the high overvoltage for nickel reduces the difference between the respective reversible potentials, thus making simultaneous deposition of both metals quite possible. On the other hand overvoltage for nickel at 90 °C is considerably lower so that the difference between the deposition potentials increases and simultaneous deposition of nickel and zinc is no l nger possible. 

Nickel reduced from the carbonate at 450° C. has no action upon a mixture of hydrogen and oxygen at ordinary temperatures, but if distributed over nine times its weight of inert substance it equals colloidal palladium in activity. It is still more active towards organic compounds if reduced at a lower temperature, such as 310° C.6... 

Various alloys of nickel and copper are of great industrial importance. The two metals mix in all proportions, the nickel reducing the conductivity and increasing the hardness of the copper. The alloys are variously known as cupro-nickel, nickel bronze, and nickel brass, whilst certain of them have special names such as monel metal, Benedict metal, nickel or German silver, etc. 

Coloured salts, e.g. those of copper, chromium, cobalt, and nickel, reduce the sensitivity of the test. 

Platinum and nickel reduce CO2 to CO strongly adsoibed on the electrode surface, as confirmed by spectroscopic measurements. 

In common with other catalysts nickel varies greatly in its activity according to the methods that have been used in its preparation. Nickel reduced at 350° to 420° C. is twice as active a dehydrating catalyst toward alcohol as nickel reduced from the same oxide at 300° to 400° C.18... 

Selective hydrogenation of enones," particularly assisted by ultrasonic irradiation," is a synthetically valuable process. Ultrasonically activated nickel reduces nitroarenes to the azoxyarene stage. On the other hand, with formic acid or ammonium formate as the hydrogen source, the reduction results in arylamines."... 

This permits an interesting insight into the mode of operation of base metal NO catalysts promoted by noble metals. We found that nickel promoted by platinum was more active for NO conversion in simulated automobile exhaust than platinum alone (13). Moreover, nickel alone was quite inactive for NO conversion except in systems where neither water nor oxygen was present then it was very active. It therefore seems probable that nickel alone does not cause true equilibrium to be attained in auto exhaust, presumably because of kinetic limitations, whereas platinum does so to a substantial extent. Once true equilibrium has been induced by the platinum, the nickel reduces and becomes active also the resultant activity is greater than could be attained with either platinum or nickel alone. This concept was supported by our recent observation that the platinum did not have to be intimately associated with the nickel to cause it to become active. A nickel catalyst became active above 371°-427°C at 138,000 gaseous hourly space velocity in simulated auto exhaust when a separate platinum catalyst was placed upstream. It is possible that some additional benefit might be obtained if the two metals were intimately associated. The extent of such benefit, however, has not yet been determined. 

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°. 

Substances which ignite spontaneously in air are also classified as highly flammable. Well-known examples are the alkali metals, many organometallic compounds, e. g., methyl lithium, dimethyl stannous, and many silanes or very fine metal dusts, e.g., Raney nickel, reduced ferrous compounds, and aluminum, which behave pyrophorically. 

The thiophene ring can also be opened up, but in a very different way. Reductive removal of the sulfur atom with Raney nickel reduces not only the C—S bonds but also the double bonds in the ring and the four carbons in the ring form a saturated alkyl chain. If the reduction follows two Friedel—Crafts reactions on thiophene the product is a 1,6-diketone instead of the 1,4-diketones from furan. Thiophene is well behaved in Friedel—Crafts acylations, and reaction occurs at the 2- and 5-positions unless these are blocked. 

Potential adverse effeets calcium carbonate interferes with radiation curing, calcium caibonate may react with pollutant (SO2) to form sulfate, fillers eontaining cadmium, cobalt, copper, iron, lead, or nickel reduce thermal stabihty, low concentration of carbon black and titanium dioxide reduces UV stability, zinc oxide decreases thermal stability, zinc oxide in combination with carbon black reduces UV stability... 

The reductive cyclization of 6>-nitrostryene (i.e., the Cadogan-Sundberg indole synthesis) has been improved by the transition metal catalyzation, selenium-based reductive cyclization, or hydrogen/Raney nickel reduced cyclizationJ... 

The chemical composition of alloy 29-4C is shown in Table 8.3. This alloy has improved general corrosion resistance to chloride pitting and stress corrosion cracking in some environments. The absence of nickel reduces the cost. 

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