KINETICS OF THE REACTIONS OF CH3O AND CD3O WITH NO

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 (200-473 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 CH-3O + NO reaction, [GRAPHICS] For the Cd3O + NO reaction at 294 +/- 2 K [GRAPHICS] and [GRAPHICS] 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 CH03NO2 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) x 10(-29) cm6s-1 in He at 297 K.