369.     BROETZ, W.  [Systematics of the Fischer-Tropsch Catalysis.]  Ztschr. Elektrochem., vol. 53, 1949, pp. 301-306; Chem. Zentralb., 1950, I, p. 1432; Chem. Abs., vol. 44, 1950, p. 2358.

      Fundamental Fischer-Tropsch reaction:  CO+2H2>CH2+H2O at atmospheric and at 5-20 atm. gage pressure between 160° and 186° is discussed.  On technical catalysts at pressures up to 10 atm. gage pressure the reaction rate is given by:  d[CO]:dt=k [H2]2:[CO] where k at 7 atm. gage pressure varies from 7.8X10-3 at 173° to 18.8X10-3 at 186°, yielding an activation energy of 31 kcol. per mol.  At atmospheric pressure an activation energy of 28 kcol. per mol. is found.  At high pressures the reaction rate is:  d[CO]:dt=k3 {H2]: [CO]}{k3[H2]: (1+k2[H2])}.  The presence of CH4 in the reaction mixture does not affect the rate or the nature of the products.  The catalysts gradually lose activity, which may be recovered by heating in H2 at 400°.  The reaction takes place directly in 1 step at the catalyst surface without formation of an intermediate carbide.  The CH2 radicals are combined at the catalyst surface under formation of double bonds at the chains ends, which are subsequently shifted by H exchange toward the center of the chains.