Sodium borohydride nickel catalyst

Reduction of the double bond only was achieved by catalytic hydrogenation over palladium prepared by reduction with sodium borohydride. This catalyst does not catalyze hydrogenation of the aldehyde group [31]. Also sodium borohydride-reduced nickel was used for conversion of cinnamaldehyde to hydrocinnamaldehyde [31]. Homogeneous hydrogenation over tris(triphenylphosphine)rhodium chloride gave 60% of hydrocinnamaldehyde and 40% of ethylbenzene [5(5]. Raney nickel, by contrast, catalyzes total reduction to hydrocinnamyl alcohol [4S. Total reduction of both the double... 

Organocopper reagents, 207 Palladium catalysts, 230 Potassium-Graphite, 252 Raney nickel, 265 Sodium acyloxyborohydrides, 277 Sodium borohydride, 278 Sodium borohydride-Nickel chloride, 279... 

Common catalyst compositions contain oxides or ionic forms of platinum, nickel, copper, cobalt, or palladium which are often present as mixtures of more than one metal. Metal hydrides, such as lithium aluminum hydride [16853-85-3] or sodium borohydride [16940-66-2] can also be used to reduce aldehydes. Depending on additional functionahties that may be present in the aldehyde molecule, specialized reducing reagents such as trimethoxyalurninum hydride or alkylboranes (less reactive and more selective) may be used. Other less industrially significant reduction procedures such as the Clemmensen reduction or the modified Wolff-Kishner reduction exist as well. 

The chain-growth catalyst is prepared by dissolving two moles of nickel chloride per mole of bidentate ligand (BDL) (diphenylphosphinobenzoic acid in 1,4-butanediol). The mixture is pressurized with ethylene to 8.8 MPa (87 atm) at 40°C. Boron hydride, probably in the form of sodium borohydride, is added at a molar ratio of two borohydrides per one atom of nickel. The nickel concentration is 0.001—0.005%. The 1,4-butanediol is used to solvent-extract the nickel catalyst after the reaction. 

The reverse reaction, namely hydrogenation, has also frequently been used to decrease the degree of unsaturation present in macrocyclic systems - typically converting imine linkages to amine groups. Such hydrogenations have usually been performed catalytically (for example, using H2 in the presence of Raney nickel or a precious metal catalyst) or by means of chemical reductants such as sodium borohydride. 

Highly active nickel, platinum and palladium catalysts can also be prepared by reducing the metal salts with sodium borohydride. 

By reduction of aldehydes and ketones Aldehydes and ketones are reduced to the corresponding alcohols by addition of hydrogen in the presence of catalysts (catalytic hydrogenation). The usual catalyst is a finely divided metal such as platinum, palladium or nickel. It is also prepared by treating aldehydes and ketones with sodium borohydride (NaBH4) or lithium aluminium hydride (LLAIH4). Aldehydes yield primary alcohols whereas ketones give secondary alcohols. 

Hydrogenation using Raney nickel is carried out under mild conditions and gives cis alkenes from internal alkynes in yields ranging from 50 to 100% [356, 357, 358, 359, 360]. Half hydrogenation of alkynes was also achieved over nickel prepared by reduction of nickel acetate with sodium borohydride (P-2 nickel, nickel boride) [349,361,362] or by reduction with sodium hydride [49], or by reduction of nickel bromide with potassium-graphite [363]. Other catalysts are palladium on charcoal [364], on barium sulfate [365, 366], on... 

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). 

Consequently, by choosing proper conditions, especially the ratios of the carbonyl compound to the amino compound, very good yields of the desired amines can be obtained [322, 953]. In catalytic hydrogenations alkylation of amines was also achieved by alcohols under the conditions when they may be dehydrogenated to the carbonyl compounds [803]. The reaction of aldehydes and ketones with ammonia and amines in the presence of hydrogen is carried out on catalysts platinum oxide [957], nickel [803, 958] or Raney nickel [956, 959,960]. Yields range from low (23-35%) to very high (93%). An alternative route is the use of complex borohydrides sodium borohydride [954], lithium cyanoborohydride [955] and sodium cyanoborohydride [103] in aqueous-alcoholic solutions of pH 5-8. 

Lactitol is a disaccharide sugar alcohol prepared by reduction of the glucose residue to a sorbitol group. It is prepared by hydrogenation of a lactose solution hydrogenation at 100°C for 6 hr and 8825 kPa with a Raney nickel catalyst produces lactitol in nearly quantitative yield (van Velthuijsen 1979 Linko et al. 1980). Hydrogenation of lactose with sodium or calcium amalgam catalysts and reduction with sodium borohydride (Scholnick et al 1975) have also been successful. 

Reduction of l,2,4-triazin-3-ones (84) with Raney nickel, zinc and acetic acid, lithium aluminum hydride, sodium borohydride, titanium(III) chloride, p-toluenethiol, hydrogen and a palladium catalyst, or electrochemically, produces 4,5-dihydro-l,2,4-triazin-3-ones (268) (78HC(33)189, p. 246, 80JHC1237), which may be further reduced to 1,4,5,6-tetrahydro-l,2,4-triazin-3-ones (269). l,2,4-Triazin-3-ones (84) with hydriodic acid and phosphorus yielded imidazoles (05LA(339)243). 3-Alkoxy-l,2,4-triazines (126) and sodium borohydride gave the 2,5-dihydro derivatives (270) (80JOC4594). 

Arene(tricarbonyl)chromium complexes, 19 Nickel boride, 197 to trans-alkenes Chromium(II) sulfate, 84 of anhydrides to lactones Tetrachlorotris[bis(l,4-diphenyl-phosphine)butane]diruthenium, 288 of aromatic rings Palladium catalysts, 230 Raney nickel, 265 Sodium borohydride-1,3-Dicyano-benzene, 279 of aryl halides to arenes Palladium on carbon, 230 of benzyl ethers to alcohols Palladium catalysts, 230 of carboxylic acids to aldehydes Vilsmeier reagent, 341 of epoxides to alcohols Samarium(II) iodide, 270 Sodium hydride-Sodium /-amyloxide-Nickel(II) chloride, 281 Sodium hydride-Sodium /-amyloxide-Zinc chloride, 281 of esters to alcohols Sodium borohydride, 278 of imines and related compounds Arene(tricarbonyl)chromium complexes, 19... 

Highly active platinum, palladium, and nickel catalysts also can be obtained by reduction of metal salts with sodium borohydride (NaBH4). 

Secondary amines can be prepared from the primary amine and carbonyl compounds by way of the reduction of the derived Schiff bases, with or without the isolation of these intermediates. This procedure represents one aspect of the general method of reductive alkylation discussed in Section 5.16.3, p. 776. With aromatic primary amines and aromatic aldehydes the Schiff bases are usually readily isolable in the crystalline state and can then be subsequently subjected to a suitable reduction procedure, often by hydrogenation over a Raney nickel catalyst at moderate temperatures and pressures. A convenient procedure, which is illustrated in Expt 6.58, uses sodium borohydride in methanol, a reagent which owing to its selective reducing properties (Section 5.4.1, p. 519) does not affect other reducible functional groups (particularly the nitro group) which may be present in the Schiff base contrast the use of sodium borohydride in the presence of palladium-on-carbon, p. 894. 

Nakano and Fujishige prepared a colloidal nickel boride catalyst by reducing nickel chloride with sodium borohydride in ethanol in the presence of polyvinylpyrrolidone) as a protective colloid.83 Catalytic activity of the colloidal catalyst was higher than P-2 Ni boride for the hydrogenation of acrylamide and markedly enhanced by the addition of sodium hydroxide in the hydrogenation of acetone.84... 

P-2 Ni Boride. 78 Nickel acetate tetrahydrate (1.24 g, 5.0 mmol) is dissolved in approximately 40 ml of 95% ethanol in a 125-ml Erlenmeyer flask. This flask is attached to a hydrogenator, which is then flashed with nitrogen. With vigorous stirring, 5.0 ml of 1M sodium borohydride solution in ethanol is injected. When gas evolution from the mixture has ceased, the catalyst is ready for use. 

Titanium(II) reagents have also been used to reduce aliphatic nitro compounds to amines halo, cyano and ester groups are not reduced. Sodium borohydride, in the presence of catalytic amounts of nickel(II) chloride, reduces a variety of aliphatic nitro compounds to amines. Nickel boride (Ni2B) is an active catalyst for reductions of primary, secondary and tertiary nitro aliphatic compounds to amines. The reduction of nitrocyclohexane (45) yields cyclohexylamine (47) as well as small amounts of dicyclohexylamine (49), the latter being formed via reaction of intermediates (46) and (48 equation 28). 

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