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.