2670.     ---------------.  [PICHLER, H.]  [Synthesis of Gasoline at 200° C. and Atmospheric Pressure.]  Ztschr. Ver. deut. Ing., vol. 79, 1935, pp. 883-885; Coal Carbonisation, vol. 1, 1935, pp. 101-103.

        In the Fischer-Tropsch process, Fe, Co, and Ni are found to be the best catalysts of the conversion of CO-H₂ into hydrocarbons.  Their action probably involves the temporary formation of carbides.  However, to obtain the best results, it has been found necessary to employ combinations with other metals in specific amounts.  Thus far the best yields have been obtained with a Co-Th-Cu-kieselguhr catalyst precipitated with soda under defined conditions.  This yielded 105-110 and even over 120 gm. of liquid hydrocarbons per m.³ of gases in a single pass, and maintained 80% of this yield after 60 days, during which period the catalyst absorbed up to 150% of its weight of hard paraffin.  After appropriate regeneration the catalyst can be used again.  The synthesis proceeds at about 200° C. and atmospheric pressure; about 75% of the original gas is converted.  Complete conversion results in the liberation of about 600 kg cal. per m.³ of gas or about 20% of the heat of combustion, therefore, the removal of the heat is an important problem and is solved by circulation of oil through the contact chamber and a steam generator for utilization of the heat extracted.  The mixture of gases for the synthesis of gasoline consists of CO and H₂ in the ratio of 1:2.  If unsaturates are desired in the products, a higher proportion of CO is used.  The S content of the synthesis gas should not exceed 0.2 gm. per 100 cu.m.  The products of synthesis from a 29:58=CO:H₂ mixture with Co catalyst, in weight %, consisted of gasol, 4% (boiling below 30°); gasoline or Kogasin I. 62% (boiling at 30°-200°); oil or Kogasin II (boiling above 200°); soldi paraffin from oil, 7% (m. p. 50°); hard paraffin from catalyst, 4% (m. p. 70°-80° or more).  The gasoline is low in antiknock properties; the octane No. of 30°-180° C. Kogasin fraction is 67 with 0.5 cc. of PbEt₄ per l. and 71.5 with 1 cc. per l.  The Kogasin II is an excellent diesel fuel.  The synthetic paraffin is of specially high purity.  An increased yield of gasoline can be obtained by subjecting the higher boiling Kogasin II to cracking by the usual methods of petroleum technology.  The unsaturated hydrocarbons in the synthesis products can be varied by altering the composition of the initial gas and the catalyst; they are important as the raw materials for the manufacture of pure higher alcohols or esters.  For the manufacture of lubricating oils (1) the fractions containing olefins are treated with 5% by weight of AlCl₃, (2) the high-boiling fractions low in olefins are chlorinated and then converted to Cl-free viscous oil by activated Al₂O₃, (3) chlorinated Kogasin with aromatic hydrocarbons is condensed in presence of AlCl₃.  Such lubricants combine a favorable viscosity index with a low settling point (-42° C. compared with –16° C.) for a commercial winter oil.