MEASUREMENT OF THE RATE COEFFICIENT OF THE REACTION CH-2-]PRODUCTS INTHE TEMPERATURE-RANGE 2200 TO 2600 K(O)

The rate coefficient of the reaction CH + O-2 --> products was determi ned by measuring CH-radical concentration profiles in shock-heated 100 -150 ppm ethane/1000 ppm O-2 mixtures in Ar using cw, narrow-linewidth laser absorption at 431.131 nm. Comparing the measured CH concentrati on profiles to ones calculated using a detailed kinetics model, yielde d the following average value for the rate coefficient independent of temperature over the range 2200-2600 K: k(CH+O2) = 10((13.99 +/- 0.12) ) cm(3) mol(-1) s(-1) The experimental conditions were chosen such tha t the calculated profiles were sensitive mainly to the reactions CH O-2 --> products and CH3 + M --> CH + H-2 + M. For the methyl decompos ition reaction channel, the following rate-coefficient expression prov ided the best fit of the measured CH profiles: h(CH3+M-->CH+H2+M) = 10 ((16.00) +/- (0.12)) exp(-42900 K/T) cm(3) mol(-1) s(-1) Additionally, the rate coefficient of the reaction CH2 + H --> CH + H-2 was determi ned indirectly in the same system: k(CH2+H) = 10(14.15(+0.2.-0.6)) cm( 3) mol(-1) s(-1) (C) 1997 John Wiley & Sons, Inc.