388.     ------.  [BRUNAUER, S., AND EMMETT, P. H.]  Chemisorptions of Gases on Iron-Synthetic-Ammonia Catalysts.  Jour. Am. Chem. Soc., vol. 62, 1940, pp. 1732-1746; Chem. Abs., vol. 34, 1940, p. 6156.

      Chemisorption experiments were performed on the following Fe-synthetic-NH3 catalysts; unpromoted catalyst containing 0.15% Al2O3, singly promoted catalyst containing 10.2% Al2O3, doubly promoted catalyst containing 1.59% K2O and 1.3 Al2O3, catalyst containing 1.07% K2O, singly promoted catalyst containing 1.03% Al2O3 and 0.19 ZrO2, and doubly promoted catalyst containing 0.35% Al2O3 and 0.08 K2O.  The weights and reduction schedule (time and temperature) are given for the preparation of these catalysts.  The chemisorptions of O2 and CO at –183° and –78°, CO2 at –78 and 0°, N2 at 400°-450°, H2 at –78° (type A) and H2 at 100° (type B) were studied on these catalysts.  From the investigation of these adsorptions individually and from their mutual inhibitory effects the following conclusions are drawn:  The CO2 chemisorption is located on the surface alkali molecules, and the 5 other chemisorptions on the surface of Fe atoms.  CO and CO2 are chemisorbed as molecules, N and H as atoms, O probably as ions.  Both the Al2O3 and K2O promoters are strongly concentrated on the surfaces of singly and doubly promoted catalysts.  The alkali promoter is very intimately mixed with Fe atoms on the surface.  The Fe surface is heterogenous; the heterogeneity probably is due to differently developed crystal faces.  The molecular CO and CO2 chemisorptions are purely surface adsorptions; O ions penetrate several layers below the surface; N and H atoms probably do not penetrate below the surface but migrate to Fe atoms located under surface promoter molecules.  Both the K2O and Al2O3 promoters give evidences of specific chemical effects.