2713.     ---------------.  [PLOTNIKOV, V. A., AND IVANOV, K. N.]  [Pyrophoric Character of Some Copper Catalysts for Methanol Synthesis.]  Jour. Gen. Chem. (U.S.S.R.), vol. 4, 1934, pp. 1003-1005; Mem. Inst. Chem., Ukrain, Acad. Sci., vol. 1, 1934, pp. 127-131; Chem. Abs., vol. 29, 1935, p. 2062.

        Admixture of 2% ZnO or Cr₂O₃ increases the stability of the Cu dispersion formed during the process of its reduction from CuO.  The ability, on contact with air, to form spontaneously centers of oxidation and the extension of this process is associated with the presence on the surfaces of adsorbed H₂ in the active state.  The preparation obtained by the reduction with CO is similar to that from H₂.  The pyrophoric process converts the Cu principally to Cu₂O.