2083.     LEGRAND, C., AND SIMONOVITCH, M.  [Utilization of Coal With Particular Reference to the Production of Oil.]  Publications Assoc. Ing. PÊcole de Mines de Mons., part 3, No. 62, 1937; Fuel, vol. 17, 1938, pp. 4-10, 41-47, 65-68, 96-104, 145-160, 217-221; Chem. Abs., vol. 32, 1938, p. 8743.

                    Survey and discussion of the technical development of the processes for the production of oil from coal by high- and low-temperature carbonization, by hydrogenation, and by synthetic processes.  The Fischer-Tropsch process works at atmospheric pressure and at a temperature not normally exceeding 200° C.  By keeping the temperature constant within limits of about 1° C., no CH₄ is obtained, but a mixture of liquid hydrocarbons and some solid paraffins.  The temperature of reaction varies with the catalyst and the composition of the gas mixture; if rich in H₂, lower temperatures must be used.  The production of synthetic gasoline from water gas is effected in the following stages:

                    (1)            C+H₂O=CO+H₂--28.4 cal.   This stage is endothermic.

                    (2)            Removal of H₂S from the crude gas.

                    (3)            Reduction of organic S content to 0.2 gm. per 100 m.³

                    (4)            CO+2H₂=(CH₂)+H₂O+48 cal.  This stage is exothermic.  The catalysts used contain Fe, Ni, or Co, all of which form carbides.  Mixed catalysts are more active and robust than single catalyst.  The best catalyst is Co, followed by Ni and then Fe; the best mixed catalyst is Co-Th precipitated on kieselguhr.  With Co a yield of 130 gm. of synthetic gasoline per m.³ of gas (CO+2H₂) can be obtained against a theoretical yield of 180 gm.  The hydrogenation yields a mixture of oil and water in proportions varying between 1:1 and 1:2.  The nearer the ratio of oil to water is to 1:1, the better is the yield of liquid products.  With Co as catalyst the oil obtained contains 62% gasoline, 4% light products, 23% middle oil, and 11% paraffin (7% in the oil and 4% on the catalyst).  The gasoline can be used directly in the motor without further purification because of its aliphatic nature.  Its antiknock value can be raised in the usual way by adding tetraethyl lead.  The middle oil is excellent Diesel oil or it can be cracked into gasoline or may be used for making alcohol or lubricating oils.