3166.     SHATWELL, H. G.  Production of Synthetic Motor Spirit With Special Reference to the Fischer-Tropsch Process.  Colliery Guard., vol. 155, 1937, pp. 1125-1126; Iron and Coal Trades Rev., vol. 135, 1937, pp. 965-966; Jour. Inst. Fuel, vol. 11, 1938, pp. 209-213; Fuel, vol. 17, 1938, pp. 1-2; Brennstoff-Chem., vol. 19, 1938, p. 345; Chem. Abs., vol. 32, 1938, p. 8105.

        Most of the subsequent work on the process since the advent of Synthol has been directed toward deciding the effect of various factors, such as composition of the initial gas mixture, nature of the catalyst, temperature and pressure in the reaction vessel, and the nature and amount of the product obtained.  It now is proposed to produce the synthesis gas of proper CO:H₂ ratio by mixing blue water gas with the essential quantity of reformed coke-oven gas.  As to catalysts, it appears that Fe, Co, and Ni, promoted by other metals and oxides, gives the best results.  It generally is agreed that Fe is the most sluggish but can be used over a longer temperature range, that Co yields a product containing a substantial proportion of olefins, and that Ni is extremely active but tends to produce CH₄ and liquid and solid hydrocarbons, which are almost entirely paraffinoid in nature.  It has been found necessary to reduce the S content of the reaction gas to a maximum of 1 gm. per 1,000 cu. ft.; search should be made for a S-tolerant catalyst.  Pressure must not be much in excess of atmospheric or alcohols and other oxygenated compounds will appear in the products.  The temperature must be controlled carefully, from 190°-200° C for Ni, 200°-210° for Co, and not above 250° for Fe-base catalysts; CH₄ is produced if these temperatures are exceeded.  As the reaction is strongly exothermic, this need for careful temperature control is difficult, and special types of reaction chambers with restricted depths of catalyst are required in order to effect easy cooling and prevent local overheating.  The products are essentially paraffinoid in nature and straight-chain for the most part.  The yield of motor fuel is relatively high but of low fuel value, whereas the diesel-oil fraction has a cetene number of 100 and is useful for blending with inferior diesel fuels, such as tar oils.  In the author’s opinion, the main disadvantage of the process, apart from the disappointing nature of the motor fuel, is the fact that it is conducted at atmospheric pressure, thus necessitating large reaction chambers and large quantities of catalyst with increased tendency to poisoning and probably a heavy capital expenditure on catalysts.

        ----------.  See abs. 757.

        SHAW, L.  See abs. 53a.