377.     BROWNING, L. C., DEWITT, T. W., AND EMMETT, P. H.  Equilibria in the Systems Fe2C-Fe-CH4-H2 and Fe3C-Fe-CH4-H2.  Jour. Am. Chem. Soc., vol. 72, 1950, pp. 4211-4217; Chem. Abs., vol. 45, 1951, p. 1861.

      Equilibrium constants for the reaction (I) CH4+2 Fe(a)=Fe2C+2H2 were reported in the temperature range 295°-350° and for the reaction (II) CH4+3Fe(a)=Fe3C(β)+2H2 in the temperature range 320°-468°.  Free energies of formation of Fe2C and Fe3C, calculated from the data for reactions (I) and (II), led to the conclusion that the formation of all mono-olefins and of saturated hydrocarbons containing more than 6 C atoms by the direct reduction of Fe2C and Fe3C in the temperature range 450°-650° K. is thermodynamically unfavorable.  The results obtained for reaction (II) agree well with those obtained at higher temperatures by Watase (abs. 3616).