Raney’s nickel

Raney predicted that many other metal catalysts could be prepared with this technique, but he did not investigate them [8], Copper and cobalt catalysts were soon reported by others [4,5], These catalysts were not nearly as active as Raney s nickel catalyst and therefore have not been as popular industrially however they offer some advantages such as improved selectivity for some reactions. Skeletal iron, ruthenium and others have also been prepared [9-13], Wainwright [14,15] provides two brief overviews of skeletal catalysts, in particular skeletal copper, for heterogeneous reactions. Table 5.1 presents a list of different skeletal metal catalysts and some of the reactions that are catalyzed by them. 

Raney Nickel [Raney Ni, Raney nickel catalyst or Raney s nickel catalyst (Refs 1, 2 2a)j. 

Raney s nickel is prepared by dissolving an alloy of nickel and aluminium in a solution of sodium hydroxide the aluminium dissolves while the nickel remains m a metallic state as a highly dispersed phase the dispersed metal is separated by filtration and used as a catalyst. 

Mineralization of the initial halide may be carried out by a reductive or an oxidative process. The reductive mineralization is performed either with metallic sodium (Las-saigne s method) or with zinc in mineral acid medium or by catalytic hydrogenation with Raney s nickel. The oxidative mineralization may be carried out in the presence of dioxygen according to Schdniger s method. It consists of burning 5-10 mg of substance in air. 

Nickel catalyst, Raney, in preparation of 2,2 -bipyridine, 46, S W7-J, preparation of, 46, S Nickel ion, as catalyst for decomposition of diazonium xanthates, 47, 107... 

For industrial hydrogenation of vegetable and animal oils in Russia a Raney type nickel was prepared by Bag and co-workers (64). Preparation of detergents from hydrogenated fats has been reported (11). Reviews of these so-called skeleton catalysts were published by Russian investigators, for instance, by Lel chuk and co-workers (197). These catalysts have also been discussed with reference to hydrocarbon synthesis from water gas (148). Lel chuk (197) states that Raney nickel is more drastic for water gas synthesis than are the skeleton nickel catalysts prepared by Bag, and that Bag s copper-nickel skeleton catalysts approach nickel in their activity. Destructive hydrogenation under mild conditions was said to be possible with Bag s skeleton catalyst as described by Lel chuk. 

Nitriles have been hydrogenated at low temperatures and pressures over heterogeneou.s and homogeneous catalysts to produce amines, aldehydes, primary alcohols or alkanes. The reduction to produce amines is by far the most widely used transformation. The most commonly used catalysts are Raney nickel, Raney cobalt, nickel boride, cobalt boride, rhodium, palladium or platinum on various supports. Products formed in the hydrogenation of a nitrile (RCN) are determined by the fate of the intermediate... 

In Raney s method a catalytically active metal is alloyed with a catalytically inactive one and then treated with a reagent that dissolves out the inactive metal. The catalytically inactive component that is to be dissolved out may be aluminum, silicon, magnesium, or zinc. The catalytically active metal is usually nickel, cobalt, copper, or iron. Noble-metal catalysts can, however, also be produced by Raney s method if an aluminum-platinum alloy (40% of platinum) or a zinc-palladium alloy (40% of palladium) is decomposed by hydrochloric acid.153... 

Preferential desulfuration. In contrast to Raney-Ni, nickel boride permits preferential desulfuration with retention of sulfone groups. Despite lower yields nickel boride surpasses Raney-Ni in non-pyrophoric character and less hazardous use as well as in case of prepn. and accurate weighing. E. s. W. E. Truce and F. M. Perry, J. Org. Chem. 30, 1316 (1965). 

Raney catalysts s. Nickel Rays s. Irradiation Reaction, terminal s. w-Halogenation -, transannular s. Transannular... 

Powders of metals were prepared in various chemical ways, by means of electrolysis, and by means of Raney s method with a different procedure in the process (different initial alloys, different temperatures of leeching, etc.). The amount by which the leading-out electrode is dipped in the powder has no influence on the measured potential value. The temperature coefficient of potential is almost equal to the values for ordinary electrodes of the first kind, in the examined temperatures from 15°C to 35°C. As for copper and nickel we have found too that powders prepared in various ways and differing in their catal3rtic properties change the potential values of powder electrodes which have the same-solutions. Such powders also differ in the values of their counted out normal potentials. 

We have investigated copper preparations (Raney s and others), Raney nickel, zinc oxide, iron oxide, vanadium quin-toxide (VjOg), silica gel (SiOj) and some varieties of silicon dioxide applied as carriers, zinc ferrocyanide pure, and with Fe + and Cu + ions, a cobalt-thorium contact for Fischer and Tropsch s s5mthesis, zinc hydroxide with Co + ions, and silica gel with nickel sulphate (II) fixed on it. We have investigated contact fixed on a carrier and without a carrier, with additions of an activator, etc. For example, Co + ions on Zn(0H)2 could be clearly detected potentiometrically and still in the quantity of 3.10 g Co + to a powder electrode. 

The anticonvulsant primidone (1035) resembles phenobarbital but lacks the 2-oxo substituent. It was introduced in 1952 and has remained a valuable drug for controlling grand mal and psychomotor epilepsy. As might be expected, primidone is metabolized to yield phenobarbital (1034 X = 0) and C-ethyl-C-phenylmalondiamide (1036), both of which have marked anticonvulsant properties however, primidone does have intrinsic activity and an appropriate mixture of its metabolites has only a fraction of its activity (73MI21303). Primidone may be made in several ways, of which desulfurization by Raney nickel of the 2-thiobarbiturate (1034 X = S) or treatment of the diamide (1036) with formic acid (at 190 °C) seem to be the most satisfactory (54JCS3263). 

This group is prepared by the reaction of the anion of 9-hydroxyanthracene and the tosylate of an alcohol. Since the formation of this group requires an S 2 displacement on the alcohol to be protected, it is best suited for primaiy alcohols. It is cleaved by a novel singlet oxygen reaction followed by reduction of the endo-peroxide with hydrogen and Raney nickel. 

The use of primary amines instead of ammonia affords l,2-dialkyl-/l -pyrrolines or l,2-dialkyl-/l -piperideines. Amino ketones with a primary amino group are intermediates in the reduction of y-nitropropylalkyl ketones (14,15) or S-nitrobutylalkyl ketones (16-18) by catalytic hydrogenation over Raney nickel or with zinc and hydrochloric acid (Scheme 1). 

Catalytic reduction of quinazolines unsubstituted in position 4 using palladium-charcoal, palladium on calcium carbonate, Raney nickel, or Adam s platinum has been used for preparing 3,4-dihydro-... 

The synthesis starts by condensation of readily available optically active (R)-(+)-alpha-methylbenzylamine with 4-phenyl-2-butanone to form an imine which is itself reduced by hy-drogenolysis (Raney nickel) to give a 9 1 mixture of the (R,R)-amine and the (R,S)-amine (4). 

The majority of analgesics can be classified as either central or peripheral on the basis of their mode of action. Structural characteristics usually follow the same divisions the former show some relation to the opioids while the latter can be recognized as NSAlD s. The triamino pyridine 17 is an analgesic which does not seem to belong stmcturally to either class. Reaction of substituted pyridine 13 (obtainable from 12 by nitration ) with benzylamine 14 leads to the product from replacement of the methoxyl group (15). The reaction probably proceeds by the addition elimination sequence characteristic of heterocyclic nucleophilic displacements. Reduction of the nitro group with Raney nickel gives triamine 16. Acylation of the product with ethyl chlorofor-mate produces flupirtine (17) [4]. 

The chiral catalyst was made from Raney nickel, which was prepared by addition in small portions of 3.9 g Raney nickel alloy to 40 ml water containing9 g NaOH. The mixture was kept at 100 C for 1 h, and then washed 15 times with 40 ml water. Chirality was introduced by treatment of the Raney nickel for I h at lOO C with 178 ml water adjusted to pH 3.2 with NaOH and containing 2g (S,S)-tartaric acid and 20 g NaBr. The solution was then decanted, and the modifying procedure was twice repeated. Hydrogenation over this catalyst of acetylacctone (100 atm, 100" C) in THF containing a small amount of acetic acid gave an isolated yield of chiral pentanediol of 44% (99.6% optical purity). 

Nickel in the presence of ammonia is often used for reduction of nitriles to primary amines. The reaction is done at elevated temperatures and pressures ( 100 C, 1000 psig) unless massive amounts of nickel are used. Cobalt is used similarly but mainly under even more vigorous conditions. Nitriles containing a benzylamine can be reduced over Raney nickel to an amine without hydrogenolysis of the benzyl group (7). A solution of butoxycarbonyl)-3-aminopropyl]-N-<3-cyanopropyl)benzylamine (13.6 g) in 100 ml of ethanol containing 4 g. NaOH was reduced over 3.0 g Raney nickel at 40 psig for 28 h. The yield of A/ -benzyl-Air -(f-butoxycarbonyl)s >ermidine was 95% (7). 

S g of ethyl glycinate hydrochloride were dissolved in 400 cc of ethanol and 33.5 g of salicylic aldehyde were added. It is refluxed for half an hour and cooled. 38 cc of triethylamlne and 25 g of Raney nickel are then added whereafter hydrogenation is carried out at room temperature and under atmospheric pressure. After hydrogen adsorption was complete, the mixture was filtered and the alcohol evaporated off. The residue was taken up with acidified water, extracted with ether to eliminate part of the by-products, consisting mainly of o-cresol, then made alkaline with ammonia and extracted with ethyl acetate. The solvent was removed in vacuo and the residue crystallized from ether/petroleum ether. 36.7 g of o-hydroxybenzyl-aminoacetlc acid ethyl ester melting at 47°C are obtained. 

The resulting 4-methylhexanone-2 oxime separates and is dried by any suitable means, such as with a dehydrating agent, for example, sodium sulfate or magnesium sulfate. After drying, 4-methylhexanone-2 oxime is reduced with hydrogen by means of a catalyst, such as Raney nickel, or by reaction of sodium and a primary alcohol, such as ethanol. The resulting 2-amino-4-methylhexane may be purified by distillation, as described in U.S. Patent 2,350,318. 

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