827.    ---------------.  [EMMETT, P. H., AND BRUNAUER, S.]   Use of Low-Temperature van der Waals Adsorption Isotherms in Determining the Surface Area of Iron-Synthetic-Ammonia Catalysts.  Jour. Am. Chem. Soc., vol. 59, 1937, pp. 1553-1564; Chem. Abs., vol. 31, 1937, p. 7322.

     Adsorption isotherms of N2 and A at 195.8; N2, A, CO, and O2 at 183; CH4 and NO at 140; N2O and CO2 at 78; NH3 at 36; and n-butane at 0 on 6 different Fe synthetic-NH3 catalysts were determined.  These isotherms together with data on the chemisorption of CO on the catalysts at 183 and 78 and for the activated adsorption of H2 appear to afford a means of measuring the absolute and the relative surface areas of the Fe catalysts.  Al2O3 promoters appear to concentrate on the surfaces of the Fe catalysts.