3353.     ---------------.  [TECHNICAL OIL MISSION.]  [Middle-Pressure Synthesis With Iron Catalysts, Sept. 9, 1939.]  Transl. of German documents on the Development of Iron Catalysts for the Fischer-Tropsch Synthesis.  Part II, 1946, pp. 11-21; TOM Reel 101, Doc. PG-21, 578-NID.

        Reviews historical development of the Fe catalyst.  It is possible to point out that Fe catalysts, which are properly pretreated with CO and are operated at slightly elevated pressures, are capable of converting a theoretical mixture of CO and H₂ into hydrocarbons over a very long period.  The total yields compare very closely to those obtained from Co catalysts, therefore, it now appears feasible to replace Co by Fe in the synthesis of hydrocarbons from CO and H₂.  Except for traces of alkali, the new Fe catalyst contains no additional material.  It must, however, be inducted at approximate atmospheric pressure and above 250° over a period of 24 hr.  The synthesis itself is best carried out at pressures 10-20 atm. and at maximum working temperatures of 230°-240°, with a synthesis gas containing CO and H₂ in the ratio of 3:2.  Higher pressures necessitate higher operating temperature, and, with water as the cooling liquid, heavier pressure apparatus is required.  Without regeneration of the Fe catalyst, constant yields of 150 gm. of liquid, gasol, and solid hydrocarbons per N m.³ of synthesis gas are obtained indefinitely.  The liquid hydrocarbon products contain approximately 66% of a benzine fraction boiling below 180° and 20% at 180°-300°.  The content of solid paraffin is about 5%.  In general, 2/3 of the benzine fraction consists of unsaturated hydrocarbons and 1/3 of saturated hydrocarbons, density 0.7 and 15°, octane number (i. G. Farbenindustrie-test engine) about 60.  The benzine can be improved materially by following the synthesis with a polymerization of the primary unsaturated hydrocarbons, thus raising the octane No. to 67; by adding 0.7 cc. of tetraethyl lead per l., the octane No. is raised to 77.