1220.    ---------------.  [GORDON, A. S.] Mechanism and Kinetics of the Thermal Decomposition of Methane in a Flowing System in the Region 1,000°-1,075° C.  Jour. Am. Chem. Soc., vol. 70, 1948, pp. 395-401.

       Mechanism and kinetics of the thermal decomposition of CH₄ have been studied in a porcelain reaction vessel using a flow system at 1,000°-1,075°.  The data were treated in accordance with the assumption that the reaction was unimolecular and homogeneous as had been reported previously for a static system up to 850°.  The reaction constants were found to increase with increasing decomposition which indicates a reaction less than first order or autocatalytic.  The latter hypothesis was tested by adding separately small % of the various product gases to the original CH₄.  It was shown that 0.72% C₂H₂ increased the reaction rate 2 to 2 ½ times its original value.  The catalysis may be a homogeneous direct attack on CH₄.  The addition of 1% of C₂H₄ likewise increased the reaction to about the same extent, but this is probably due to the C₂H₂ which is rapidly formed from the C₂H₄.  Addition of 2% H₂ to the reactant CH₄ also gives a 20-30% increase in reaction rate with a concurrent increase in C₂H₂ content, which accounts for at least part of the effect on the reaction rates.  Larger concentrates of H₂ had previously been shown markedly to slow the rate of decomposition.  By increasing the surface : volume ratio about fourfold, the rate of decomposition is about 2 ½ times as great, part of the effect arising from an increased % of C₂H₂.