2295.     MITTASCH, A., AND KEUNECKE, E.  [Aluminum Oxide Activation of Iron Catalysts for Synthesis of Ammonia.]  Ztschr. Elektrochem., vol. 38, 1932, pp. 666-669; Chem. Abs., vol. 26, 1932, p. 5707.

        Fe catalysts containing about 10% Al₂O₃ have been prepared by different methods and their relative activities for NH₃ synthesis have been determined.  Preparation of the Fe oxide-Al oxide by fusion, by coprecipitation followed by ignition in air to either 1,000° or 500°, by mixing the precipitated Fe₂O₃ with either a-or γ-Al₂O₃ and igniting to 1,100°, and by mixing γ-Al₂O₃ with precipitated Fe₂O₃ and igniting in air to 500°, all gave catalysts on reduction with H₂ that were capable of producing between 8.5 and 11.6% NH₃ at 500°, 200 atm. and space velocity of 20 l. per hr.  Mixing precipitated Fe₂O₃ with a-Al₂O₃ and igniting to 500° gave a very poor catalyst.  Fe prepared by the reduction of pure Fe₂O₃ gave a catalyst whose initial activity is as high as the final activity of the samples promoted with Al₂O₃; the principal function of the promoter appears, therefore, to be the prevention of crystal growth in the reduced Fe catalysts.