Reductions with nickel aluminum alloy

Reductions with Nickel-Aluminum Alloy and Aqueous Alkali.426... 

Naphthalene is reduced to 1,4-dihydronaphthalene by sodium and alcohol. Isomerization of this product to 3,4-dihydronaphthalene occurs with sodamide in liquid ammonia. Tetrahydronaphthalene (tetralin) is formed from naphthalene by sodium in amyl alcohol or by reduction with nickel-aluminum alloy and aqueous alkali. Catalytic hydrogenation of naphthalene can be stopped at the tetralin stage over copper chromite, Raney nickel, or alkali metal catalysts. cis-Decahydronaphthalene is produced by high-pressure hydrogenation of tetralin over Adams catalyst, whereas a mixture of cis- and trans-decalins is obtained from naphthalene under the same conditions. ... 

Olefinic acids have been reduced to saturated acids in excellent yields by a variety of methods. Catalytic hydrogenation at room temperature over platinum oxide catalyst is described for 4-phenyl-3-pentenoic acid (98%). Behenic and undecanoic acids are prepared from the naturally occurring erucic and undecylenic acids with this catalyst. New and "aged platinum oxide catalysts have been compared, Reduction by nickel-aluminum alloy has been preferred to catalytic hydrogenation over platinum catalyst in the preparation of y-isopropylvaleric acid. ... 

S 129), and 3-hydrazinopyridazines are reduced to the corresponding amines (80S830). With nickel-aluminum alloy in potassium hydroxide solution, reduction proceeds with N—N bond cleavage to the 1,4-diaminobutanes (87JOC1043). Similarly, 1,2,3,6-tetrahydropyridazines were cleaved hydrogenolytically and transformed into a derivative of 2,5-diamino-2,5-didesoxyribose (80LA1307). 

Surprisingly good results in the reduction of aromatic ketones were obtained in treating the ketones with a 50% nickel-aluminum alloy in 10-16% aqueous sodium hydroxide at temperatures of 20-90° (yields 65-90%) [769, 827]. 

Reduction of unsaturated ketones to saturated alcohols is achieved by catalytic hydrogenation using a nickel catalyst [49], a copper chromite catalyst [50, 887] or by treatment with a nickel-aluminum alloy in sodium hydroxide [555]. If the double bond is conjugated, complete reduction can also be obtained with some hydrides. 2-Cyclopentenone was reduced to cyclopentanol in 83.5% yield with lithium aluminum hydride in tetrahydrofuran [764], with lithium tris tert-butoxy)aluminium hydride (88.8% yield) [764], and with sodium borohydride in ethanol at 78° (yield 100%) [764], Most frequently, however, only the carbonyl is reduced, especially with application of the inverse technique (p. 21). 

Other reagents which have occasionally been used to cleave hydrazides include diborane (which also reduces the carbonyl groups), sodium naphthalenide, 0,0-diethyldithiophosphoric acid, (EtO)2PS2H, - and sulfur monochloride. Nickel-aluminum alloy in aqueous methanolic potassium hydroxide is a good reagent for reductively cleaving a number of N—N bonded compounds, such as A -methyl-A -phenylhydrazine and Af/Z-dimethylnitrosamine. - Nitrosamines have also been cleaved with titanium(IV) chloride-sodium borohydride and lithium aluminium hydride. 

Graham and Williams9 found nickel-aluminum alloy with aqueous sodium hydroxide to be a useful reagent for the reduction of ketoximes to amines without rearrangements that often accompany aluminum hydride reductions. 

Kametani and Nomura have described another very interesting catalytic reduction without the use of gaseous hydrogen. They have found that various nitriles can be reduced to amines by utilizing the hydrogen formed in situ by reacting Raney nickel-aluminum alloy with aqueous alkali. In this manner, they have prepared various benzylamines and phenylethylamines. 

Oxazoles can be reduced to afford ring-opened products or oxazolines, depending on the reaction conditions. For example, Lunn investigated the reduction of heterocycles with a nickel-aluminum alloy in aqueous potassium hydroxide. 

Raney nickel is a highly active, finely divided form of the metal prepared by reaction of a nickel/aluminum alloy with concentrated sodium hydroxide, which removes most of the aluminum as Na[Al(OH)4], Although active for a very wide range of reductions, it has been particularly widely used for the reduction of nitriles, and the desulfurization of thioacetals, thioethers, and dithianes (see Section 19.3.3) (Figure 23.22). The careful disposal of the catalyst after use is very important once it has dried out, the metal is highly pyrophoric. 

Cyanoanthracene, 50,55 p-Cyanobenzenesulfonamide, reduction with Raney nickel alloy to p-for-mylbenzenesulfonamide, 51,20 p-Cyano-N,N-diethylaniline, 50, S4 Cyanohydrins, formation by use of alkyl-aluminum cyanides, 52, 96... 

Powder Formation. Metallic powders can be formed by any number of techniques, including the reduction of corresponding oxides and salts, the thermal dissociation of metal compounds, electrolysis, atomization, gas-phase synthesis or decomposition, or mechanical attrition. The atomization method is the one most commonly used, because it can produce powders from alloys as well as from pure metals. In the atomization process, a molten metal is forced through an orifice and the stream is broken up with a jet of water or gas. The molten metal forms droplets to minimize the surface area, which solidify very rapidly. Currently, iron-nickel-molybdenum alloys, stainless steels, tool steels, nickel alloys, titanium alloys, and aluminum alloys, as well as many pure metals, are manufactured by atomization processes. 

Reduction of 83 (R = H, R = CH2Ph, R" = C6H4S03H) with Raney nickel alloy and sodium hydroxide gave 1-benzyldioxindole and with lithium aluminum hydride gave 1-benzylindoline.216... 

Some firearms are plated with anodized aluminum, nickel, or chromium which gives durability and good looks, and some are made from stainless steel which is much less prone to rust than conventional steel. Electroless nickel coating is an alloy coating of 88% to 96% nickel and 4% to 12% phosphorus, which is produced by chemical (not electrical) reduction of nickel on to the metal surface. 

Oxygen is the common cathodic reduction species found in water, which is responsible for continued corrosive attack on some engineering materials, such as low carbon steel. However, passive engineering alloys utilize the oxygen to form thin, tenacious, and adherent protective oxide films. Some common alloys with protective films are stainless steels, nickel alloys, copper-base alloys and aluminum alloys. The oxygen concentration at ambient temperatures and atmospheric pressure is approximately 6-8 mg/L. An increase in temperature decreases oxygen solubility, whereas an increase in pressure increases oxygen solubility. 

Diaminopyridine has been prepared by reduction of 2-amino-3-nitropyridine with iron and aqueous acidified ethanol,3 tin and hydrochloric acid,6 or stannous chloride and hydrochloric acid,6 by catalytic reduction of 3-amino-2-nitropyridine,6 by reduction of 3-amino-2-nitropyridine,7 2-amino-5-chloro-3-nitro-pyridine,8 or 2-amino-5-bromo-3-nitropyridine 4 with sodium hydroxide solution and an aluminum nickel alloy, and by catalytic reduction of 2-amino-5-bromo-3-nitropyridine.4 Animation of... 

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