825.    ---------------.  [EMMETT, P. H., AND BRUNAUER, S.]    Accumulation of Alkali Promoters on Surfaces of Iron-Synthetic-Ammonia Catalysts.  Jour. Am. Chem. Soc., vol. 59, 1937, pp. 310-315; Chem. Abs., vol. 31, 1937, p. 2915.

    By comparing the adsorption isotherms for N2 at 183, CO at 183, and CO2 at 78 on various Fe-synthetic-NH3 catalysts, evidence was obtained to show that a % or so of K2O in the catalysts will actually cover more than 50% of the surface of the reduced catalyst.  Apparently the chemisorption of CO at 183 occurs principally on surface Fe atoms, whereas the chemisorption of CO2 at 78 occurs on such surface promoter molecules as contain alkali.