1241.    ---------------.  [GREAT BRITAIN FUEL RESEARCH BOARD.] Synthesis of Hydrocarbons and the Production of Lubricating Oils.  Rept. for the Year Ended March 1938.  H. M. Sta. Office, London, pp. 186-206.

        Investigations have extended from a study of the mechanism of the synthesis, through laboratory-scale and semi-technical-scale plant work, to an examination of the quality of the products under practical conditions.  Investigation of the mechanism leads to the conclusions that carbide formation proceeds much more rapidly when CO reacts at 200° with an active Fischer catalyst than with ordinary reduced Co; that the carbide formed reacts very readily with H₂ to give a gas consisting mainly of CH₄ and a small % of higher hydrocarbons; that the rate of reaction of the carbide with H₂ is very much greater than its rate of formation from CO and the catalyst.  By studying the o-p-H₂ conversion on the catalyst during the synthesis reaction, it is found in general that, if the conversion is being catalyzed by a metal, absorbed H atoms are present on the metal surface; and, if on the other hand, conditions are such that no absorbed H atoms can be formed on the surface, the metal will not catalyze the o-p conversion.  The results of experiments show that when the product is higher hydrocarbons, no H atoms are detectable on the surface, but when the product is CH₄, H atoms are there.  Thus it seems reasonable to conclude that, if the chemisorbed CO is attacked by adsorbed H atoms, the product will be CH₄, but attack by molecular H₂ leads ultimately to higher hydrocarbons.  Previous difficulties in catalyst preparation have been largely removed and a satisfactory composition has been found in Co:ThO₂:kieselguhr=100:18:100.  Before the semi-technical-scale plant runs, described in detail, the catalysts was reduced in H₂ at 350°, compared with the operating synthesis temperature of 180°-230°.  The highest yield of recovered oil product was 77.0 gm. per N m.³ of synthesis gas (exclusive of lighter constituents).  This yield has later been improved to 90-100 gm. per m.³  The crude product consists almost entirely of straight-chain paraffins and olefins, from the lightest member of the series up to wax having a melting point above 100°.  Appropriate fractions may be used as motor fuel and diesel oil, the former of very low antiknock value (30 by the Cooperative Fuel Research Committee method), the latter with a high cetene number (93).  Important possibilities of the process lie in the polymerization with AlCl₃ of the unsaturated constituents of the product to form lubricating oil, considerable details of which are presented.  Some experiments have been carried out on the oxidation of the wax for the production of fatty acids, and it has been shown possible to produce a soap by this means.  The procedure is to oxidize the wax at 100°-130° with 0.25-0.5% Mn resinate as catalyst.  The only point in which the synthetic lubricating oils failed to pass the test with respect to increase of viscosity on oxidation associated with formation of acidic and saponifiable substances.