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Urushibara nickel-zinc

Benzonitrile added to Urushibara nickel-zinc catalyst (s. Synth. Meth. 12, 93) in water, and refluxed ca. 8hrs. until the oil drops of benzonitrile on the water have disappeared benzamide. Y 78%. — Water as solvent suppresses the activity of the catalyst for hydrogenation but promotes the activity for hydration. F. e. s. K. Watanabe, Bull. Ghem. Soc. Japan 37, 1325 (1964). [Pg.55]

X-ray photoelectron (XPS) studies of nickel boride, nickel phosphide, Raney nickel and Urushibara nickel showed that the electron density on the nickel was a function of the other metal present in these catalysts. 28J29 Boron, aluminum (Raney nickel) and zinc (Urushibara nickel) all increased the electron density on the nickel while phosphorous was an electron acceptor. Comparing the electron densities on the nickel in these catalysts with that on a nickel black prepared by the thermal decomposition of nickel formate (D-Ni) gave the series Ni-B > Ni-Al > Ni-Zn > D-Ni > Ni-P. [Pg.251]

A nickel catalyst analogous to Raney nickel is Urushibara nickel [21], produced by adding zinc dust to a solution of a nickel salt, generally nickel chloride. The zinc reduces the nickel to metallic nickel, which precipitates as very small particles mostly on the metallic zinc. The precipitate contains metallic zinc, zinc... [Pg.21]

Nickel precipitated from aqueous solutions of nickel chloride by aluminum or zinc dust is referred to as Urushibara catalyst and resembles Raney nickel in its activity [48. ... [Pg.9]

Various active nickel catalysts obtained not via reduction of nickel oxide with hydrogen have been described in the literature. Among these are the catalysts obtained by the decomposition of nickel carbonyl 10 by thermal decomposition of nickel formate or oxalate 11 by treating Ni-Si alloy or, more commonly, Ni-Al alloy with caustic alkali (or with heated water or steam) (Raney Ni) 12 by reducing nickel salts with a more electropositive metal,13 particularly by zinc dust followed by activation with an alkali or acid (Urushibara Ni) 14-16 and by reducing nickel salts with sodium boro-hydride (Ni boride catalyst)17-19 or other reducing agents.20-24... [Pg.3]

Urushibara Ni A (U-Ni-A) 6 The solids prepared by the reaction of zinc dust with aqueous nickel chloride solution, in the same way as described above, are transferred into 160 ml of 13% acetic acid and digested at 40°C until the evolution of hydrogen gas subsides or the solution becomes pale green. The catalyst can be washed with water on a glass filter under gentle suction with care to prevent the catalyst from contacting air, and then with the solvent for hydrogenation. [Pg.19]

The precipitate of nickel obtained on adding zinc dust to a solution of nickel chloride can be activated by treatment with aqueous ammonia (Urushibara Ni—NH3). This nickel catalyst contains appreciable amounts of residual ammonia and is suitable for reduction of nitriles to amines. Treating the nickel precipitate with sodium hydroxide solution gives the Urushibara Ni—B catalyst Urushibara Co—B catalyst is obtained analogously from cobalt chloride.180... [Pg.25]


See other pages where Urushibara nickel-zinc is mentioned: [Pg.300]    [Pg.285]    [Pg.300]    [Pg.285]    [Pg.19]    [Pg.249]    [Pg.250]    [Pg.22]    [Pg.19]    [Pg.623]   
See also in sourсe #XX -- [ Pg.12 , Pg.93 ]




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