3243.     SPENGLER, H.  [Physicochemical Behavior of Fischer-Tropsch Catalysts.]  Erdöl u. Kohle, vol. 3, o. 1, 1950, p. 10.

        Paper presented at the 1949 meeting of the Deutsche Gesellschaft Mineralölwissenschaft u. Kohlechemie.  Aside from the purely chemically limited properties, the physical or physical-chemical data for the behavior of a catalyst is important.  Of special significance for the movements occurring within are the geometric structure of the catalyst grains, the inner surface area as the seat of the catalytic grains, the inner surface area as the seat of the catalytic reactions, and the adsorption behavior in the presence of the reaction gases.  Measurements of the geometric structure give numerical values for the porosity of the catalyst grains and the dimensions of the pores.  Tests of the permeability of the catalyst grains with different gases show that greater amounts of H₂ and CO pass through the grain than must be the case with experimentally determined pore radii.  This additional flow is called surface diffusion.  It explains the otherwise difficultly explicable fact that the whole catalyst grain is utilized by the reaction, although the pores are filled with the products of the reaction.  The inner surface area of a Co catalyst lies in the magnitude of 100 m.³ per gm.  In the range of adsorption measurements for determination of the inner surface area, the adsorption of CO and H₂ was measured also.  From the measurements, it was seen that the CO molecule is more strongly bound than is the H₂ molecule, and the temperature range applied in the Fischer-Tropsch synthesis lies within the transition range of physical and chemical adsorption.

        ----------.  See abs. 370.