Raney nickel hydrogen transfer

MA chain transfer, 244, 253 MA monomer, 239, 243-253, 259 Radical polymerization initiators, for polyester crosslinking, 487-491 Raman spectroscopy, MA spectrum, 8 Raney nickel hydrogenation catalyst, 42 7-Rays, polymerization initiation, 239-241,... 

Among the earlier studies of reaction kinetics in mechanically stirred slurry reactors may be noted the papers of Davis et al. (D3), Price and Schiewitz (P5), and Littman and Bliss (L6). The latter investigated the hydrogenation of toluene catalyzed by Raney-nickel with a view to establishing the mechanism of the reaction and reaction orders, the study being a typical example of the application of mechanically stirred reactors for investigations of chemical kinetics in the absence of mass-transfer effects. 

Mikkola, J.P., Salmi, T., and Sjoholm, R. (1999) Modelling of kinetics and mass transfer in the hydrogenation of xylose over Raney nickel catalyst. /. Chem. Technd. Biotechnol, 74, 655—662. 

Chiral amines were always considered important targets for synthetic chemists, and attempts to prepare such compounds enantioselectively date back to quite early times. Selected milestones for the development of enantioselective catalysts for the reduction of C = N functions are listed in Table 34.1. At first, only heterogeneous hydrogenation catalysts such as Pt black, Pd/C or Raney nickel were applied. These were modified with chiral auxiliaries in the hope that some induction - that is, transfer of chirality from the auxiliary to the reactant -might occur. These efforts were undertaken on a purely empirical basis, without any understanding of what might influence the desired selectivity. Only very few substrate types were studied and, not surprisingly, enantioselectivities were... 

Hydrazine is a very effective hydrogen donor in the catalytic transfer of hydrogen achieved by refluxing compounds to be reduced with hydrazine in the presence of Raney nickel [277,278,279] (p. 13). 

The electrochemical hydrogenation of double bonds can be performed either electrocatalytically at Raney nickel, palladium, or platinum modified electrodes [32] or via electron transfer under Birch conditions to the intermediate anion radical [33]. Examples are given in the dihydrogenation of phthalic acid (Eq. 22.15) and the hydrogenation of heteroaromatic compounds (Eq. 22.14). 

Transfer hydrogenation of nitroarenes. Transfer hydrogenation of the ni-troarene 2 with Raney nickel and isopropanol as the hydride donor results in the... 

Lemcoff and Jameson71 measured the volumetric gas-liquid mass-transfer coefficient during hydrogenation of acetone in a vibrating slurry reactor. They correlated the data obtained with Raney nickel Nicat 102 catalyst (92 percent nickel) to the temperature (in the range 7 through 21 °C) and the frequency of oscillation /. The correlation is graphically illustrated in Fig. 9-25 and analytically-represented by the equation... 

Selective reduction to hydroxylamine can be achieved in a variety of ways the most widely applicable systems utilize zinc and ammonium chloride in an aqueous or alcoholic medium. The overreduction to amines can be prevented by using a two-phase solvent system. Hydroxylamines have also been obtained from nitro compounds using molecular hydrogen and iridium catalysts. A rapid metal-catalyzed transfer reduction of aromatic nitroarenes to N-substituted hydroxylamines has also been developed the method employs palladium and rhodium on charcoal as catalyst and a variety of hydrogen donors such as cyclohexene, hydrazine, formic acid and phosphinic acid. The reduction of nitroarenes to arylhydroxyl-amines can also be achieved using hydrazine in the presence of Raney nickel or iron(III) oxide. ... 

Palladium in the form of Pd black or Pd/C is the most effective catalyst. Although Raney nickel has been used, there is doubt that it serves only as a hydrogen transfer catalyst because it contains a considerable amount of adsorbed hydrogen. Platinum and rhodium have been found to be ineffective. Both alkenes and alkynes have been hydrogenated and syn addition to 1,2-diphenylacetylene has been demonstrated. ... 

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