3367.     TEMKIN, M., AND KIPERMAN, S.  [Kinetics of Synthesis and Decomposition of Ammonia on Various Catalysts.]  Jour. Phys. Chem. (U.S.S.R.) (in Russian), vol. 21, 1947, pp. 927-952; Chem. Abs., vol. 42, 1948, p. 2501.

        Equation for the rate v of reaction v=k₁P₁(P³₂/P²₃)a-k₂(P²₃)¹-a, in which P₁, P₂, and P₃ are the partial pressures of N₂, H₂, and NH₃, respectively, and k₁, k₂, and a are constant.  The energy of activation is expressed as a function of a.  The best composition of the gas mixture is given by P₂:P₁=3a.  The above equation is valid only when the system is not too far removed from the equilibrium state.  Variations of the adsorbed amount of N₂ may cause the decomposition of NH₃ to be a zero-order reaction at very low NH₃ concentrations.  Considerations of earlier experiments shows that he equation is valid for various catalysts (Fe, Mo, W, U, Ce, Mn, Os, Ru, Cu, and Pt), that a usually is 0.5 and that the activation energy is almost independent of the nature of the catalyst.  This proves that the reaction mechanism is identical on various catalysts.  The rate of synthesis should depend on the degree of uniformity of the catalyst surface.  57 refs.