2684.     ---------------.  [PICHLER, H., AND MERKEL, H.]  [Chemical and Magnetochemical Investigations of Iron Catalysts Used in Fischer-Tropsch Synthesis.  I.]  Brennstoff-Chem., vol. 31, 1950, pp. 1-9; Bureau of Mines Tech. Paper 718, 1949, pp. 16-45; Chem. Abs., vol. 44, 1950, p. 3696.

        Composition of Fe catalysts used in medium-pressure syntheses was studied by means of acid decomposition.  The activity of the catalysts increased with increasing formation of carbide during carburization.  In synthesis, the large amount of carbide present after pretreatment decreased during the 1^st day of operation to 0.2-0.4 gm. of carbidic C per 10 gm. Fe in an active catalyst.  There was a corresponding increase in the O content to 0.1-0.2 gm. per 10 gm. Fe.  The catalysts maintained this carbide-oxide equilibrium for months.  Acid decomposition of catalysts whose activity had decreased (contraction less than 40%) showed, at most, 0.1 gm. carbidic C per 10 gm. Fe and a correspondingly high O content.  (See abs. 2683).