1303. ---------------. [HAENSEL, V.] New Version of Fischer-Tropsch Reaction Gives 90% Yields of Isoparaffins. Nat. Petrol. News, Tech. Sec., vol. 37, 1945, pp. R955-R956.

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Literature Abstracts

Report of the U. S. Technical Oil Mission giving details of a laboratory-scale investigation of a 1-step synthesis carried out at the Kaiser Wilhelm Institut für Kohlenforschung, Mulheim. The 1-step synthesis of isoparaffins by the Fischer-Tropsch process can be performed by first producing higher alcohols (primarily isobutanol), then dehydrating the alcohols, and finally hydrogenating the olefins to the corresponding isoparaffins. Synthesis gas for the reaction is preferably in the ratio of 1.2CO:1H₂ instead of 1CO:2H₂. The reaction is carried out at 450° and 30 atm. It does not take place at atmospheric pressure, but as the pressure is increased yields improve. Above 300 atm. O₂-containing compounds begin to be formed and in increasing quantities. The throughput is about 5-10 times higher than in the regular Fischer-Tropsch process. Over 90% of the C₄ and C₅ fractions in the products are iso-compounds, as compared to 10-15% in the normal reaction using Co or Fe catalyst. The yield of product varies 60-120 gm. of C₄ fraction and higher; depending upon the catalyst, the yield of C₄ and higher fraction is 80 gm. per m.³ of gas; that of C₃H₈, 10 gm. The products are as follows: C₄H₁₀ (90% isobutane), 60-70% by weight; C₅H₁₂ (96-98% isopentane), 20-30%; C₆C₇ and C₈, small amounts. The C₆ fraction contains no neohexane, but primarily 2 and 3 methyl pentanes and no n-hexane. Some naphthenes have been found in the higher-boiling fraction. The yield of C₆-C₈ fraction is higher at the lower temperature. Some alcohols, amounting to less than 10% of the hydrocarbons, a small amount of MeOH, and a large amount of isobutanol also are formed. The end gas from the synthesis consists of: CO₂, 30; N₂, 20; CH₄, 10%; and the rest CO and H₂. Catalysts found suitable are mainly oxides of Zn, Al, and Th used alone or in combination. Details are given on the preparation of the catalysts.