| Abstract: | The pyrolysis of 1 and 2% ethane in krypton has been studied in shock waves by the laser-schlieren technique over 1700–4800 K. For 2400–2800 K an effective zero density gradient is seen following the rapid dissociation of the ethane. Through simulation with various mechanisms it is evident that the high rates for the dissociative recombination reactions of methyl radicals  obtained in recent shock-tube studies, are incompatible with this observation; these rates must be reduced at least an order of magnitude. On the basis of theory and previous low-temperature (T) measurements, k = 7.8 × 1011 (-6562/T) (cm3/mol s) is recommended for the second of these reactions. |
