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Literature Abstracts

 1574.    ---------------.  [IPATIEFF, V. N.]  [Catalytic Synthesis of Methane.]  Jour. Prakt. Chem., vol. 87, 1913, pp. 479-487; Jour. Russian Phys.-Chem. Soc., vol. 45, 1913, pp. 433-442; Chem. Zentralb., 1913, II, p. 234;  Chem. Abs., vol. 7, 1913, p. 3126.

        It has been assumed that the catalytic synthesis of CH₄ from C and H₂ in presence of reduced Ni is facilitated by the formation of hydrides of the metal.  Ipatieff ascribes catalysis to the presence of metallic oxides, which may serve both as oxidizing and reducing agents.  In this case the scheme is as follows:  Actor H-NiO catalyzer; Actor H-C acceptor.  The NiO oxidizes the C to CO₂, and the latter is reduced by the H₂ according to the reversible reaction:  CO₂+4H₂=CH₄+2H₂O.  As the H₂O produced is decomposed by the metal with regeneration of metallic oxide, the process is continuous, a small amount of the latter being enough for synthesizing a considerable amount of CH₄.  The correctness of this view is supported by the fact that at least a small amount of H₂O is necessary in this, as in many other reactions and that the reaction represented by the above equation is reversible.  This is proved by numerous experiments made at different temperatures and pressures, and with different concentrates of the gases.  The results of these experiments are summarized as follows:  The reduction of CO₂ by H₂ does not go to completion, whether the H₂ or the CO₂ is in excess; when a large excess of CO₂ is used, the relative amount of H₂ left unchanged decrease with an increase in the original concentrate of the CO₂; both NiO and reduced Ni catalyze the reduction, while CuO is considerably less effective; with theoretical amounts of the 2 gases the reaction of reduction tends to reach a certain limit.  Several tables illustrate the results.