2679.     PICHLER, H., AND BUFFLEB, H.  [Behavior of Ruthenium Catalysts in Synthesis of Paraffin Hydrocarbons of High Molecular Weight.]  Brennstoff-Chem., vol. 21, 1940, pp. 273-280; Chem. Zentralb., 1941, I, p. 1118; Chem. Abs., vol. 36, 1942, p. 2253.

        Activity of the catalyst was the same whether it was first reduced with H₂ or with 2H₂+CO at atmospheric pressure, or was reduced directly with synthesis gas under pressure without pretreatment.  The normal gas rate used was 5 l. per hr. with 3 gm. of Ru; with falling gas rate, the conversion into liquid and solid hydrocarbons rose to approximately the theoretical value.  The yield per hr. reached a maximum (300-350 gm. per l. of catalyst space) at a gas rate of 10 l. per hr. per gm. of Ru.  Data on the variation of the yield with temperature and pressure are tabulated.  Yields remained approximately constant over 200 days’ operation at 195° per 100 atm., and thereafter slowly diminished; after 560 days, when the temperature had been raised to 215°, the yield was 140 gm. per m.³, that is, only 10% less than the initial value.  Addition of alkali (K₂CO₃) to the catalyst had little influence on its activity or on the ratio of liquid to solid hydrocarbons in the product.  Addition of H₃PO₄ or phosphates did not improve the catalyst.  By carrying out the synthesis with a Ru catalyst suspended in H₂O at 150°, a high proportion of paraffins of high melting point, insoluble in boiling C₆H₆, was obtained.  Briefly discusses the mechanism of the reaction.