175.    BEEBE, R. A., AND STEVENS, N. P.  Heats of Adsorption of Gases on Iron-Synthetic Ammonia Catalysts at Low Temperatures.  Jour. Am. Chem. Soc., vol. 62, 1940, pp. 2134-2140; Chem. Abs., vol. 34, 1940, p. 6515.

                  Data are given for the adsorption isotherms of the following gases on doubly promoted Fe catalysts containing 1.59% K₂O and 1.3% Al₂O₃, O₂, CO, N₂, A, and H₂ at –183°, CO₂ and CO at –78°, and CO at 0°.  The heats of adsorption are given for these gases on this catalyst and on an unpromoted pure Fe catalyst containing 0.15% Al₂O₃ impurity.  These measurements indicate that the adsorption of N and of A at –183° is exclusively of the van der Waals type; that the adsorption of H at –183° and of CO at –183°, -78° and 0° is in part chemisorption; and that CO₂ is chemisorbed on the alkali-promoted catalyst at –78°, although the adsorption of this gas on the pure catalyst is exclusively van der Waal’s.  These conclusions are in general agreement with those of Emmett and Brunauer (see abs. 388) on an analysis of the low-temperature isotherms.  The heat evolved in the irreversible adsorption of O at –183° approaches, in order of magnitude, that of Fe oxide formation.  The form of the time-temperature curves with O at –183° indicates that the adsorption process involved is complex.