934.    [FINZEL, T. G.]  Pyrophoric Iron.  II.  Adsorption of Carbon Dioxide and Ammonia and the Use of Pyrophoric Iron in the Ammonia Synthesis.  Jour. Am. Chem. Soc., vol. 52, 1930, pp. 150-156; Chem. Abs., vol. 24, 1930, p. 1275.

     Relations between pyrophoric activity and adsorptive and catalytic properties were investigated.  Adsorption of CO2 by pyrophoric Fe is no criterion for pyrophoric activity; adsorption seems to depend primarily upon the amount of residual oxide contained in the Fe.  Sensitivity and ease of inactivation of pyrophoric Fe may be due to rapid recrystallization, the processes of which are hindered by the presence of cores of Fe2O3 in the particles.  Fe prepared from colloidal Fe2O3 is worthless as a catalyst in the synthesis of NH3.