The kinetics of the reactions of CH3O and CD3O with NO have been studied using a discharge flow reactor. CH3O and CD3O were detected using laser-excited fluorescence (LEF) near 300 nm. Total rate coefficients for the reaction of CH3O with NO were measured as a function of temperature (220-473 K) and pressure (0.75-5.0 Torr) of He or Ar. Total rate coefficients for the CD3O + NO reaction were measured at ca. 294 K over the pressure range 0.75-5.0 Torr He. Using molecular-beam mass spectrometry, the CH3ONO yield of the CH3O + NO reaction was measured at 297 K (0.5 and 1.0 Torr) and 223 K (1.0 Torr), showing that disproportionation to H2CO + HNO is the major channel at low pressures. These results were combined to obtain the following expressions for the disproportionation and low-pressure recombination rate coefficients. For the CH3O + NO reaction, kDISP = (1.3 ± 0.4) × 10-12 exp[(250 ± 100)/T] cm3 s-1, kOIII = (1.8 ± 1.3) × 10-29 (T/300)-(3.2 ± 0.5) cm6 s-1 For the CD3O + NO reaction at 294 ± 2 K kDISP = (3.0 ± 0.4) × 10-12 cm3 s-1 and kOIII = (2.5 ± 0.4) × 10-29 cm6 s-1 While the uncertainty associated with the measured rate coefficients is ca. ±15%, the product channel-specific rate coefficients obtained from these expressions are less certain, ca. ±50%. Using MBMS, the CH3NO2 yield of the CH3 + NO2 reaction was measured at 297 K (0.5 and 1.0 Torr) and 223 K (1.0 Torr). Combined with the previously reported rate coefficient, these results indicate a low-pressure, third-order recombination rate coefficient of (6 ± 2) × 10-29 cm6 s-1 in He at 297 K.
|Original language||English (US)|
|Number of pages||9|
|Journal||Journal of the Chemical Society, Faraday Transactions|
|State||Published - Dec 1 1990|
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry