779.    EICHNER, C., PERRIN, M., AND PRETTRE, M.  [Controlled Catalytic Combustion of Methane.]  Compt. Rend., vol. 218, 1944, pp. 621-623; Bull. Soc. Chim., 1944, p. 388; Chem. Abs., vol. 40, 1946, p. 1643.

     With a limited O₂ supply, possible reactions are:  (1) 2CH₄+O₂=2CO+4H₂; (2) CH₄+20₂=CO₂+2H₂O; (3) 2CH₄+30₂=2CO+4H₂O; (4) CH₄+O₂=CO₂+2H₂; residual CH₄ and reaction products may give (5) CH₄+H₂O=CO+3H₂ and (6) CO+H₂O=CO₂+H₂, 2 independent reactions.  A mixture of O₂ and CH₄ entering a catalytic column previously brought to constant temperature produces an initial rise followed by a drop in temperature; this indicates at least 2 steps to the reaction; only (5) is endothermic.  Equilibria (1) and (5) give very poor yields below 1,000°.  Composition of gases after reaction indicates (4) does not occur.  Calculated and experimental results for equilibria (5) and (6) compare well at 725°-870°.  When equilibrium is not attained, analyses show (2) to be the preferred mechanism; an excess of H₂O and CO₂ is found in the gas mixture leaving the column; (3) sometimes occurs.