Journal of Physical Chemistry, Vol.100, No.32, 13624-13628, 1996
Direct Kinetics Study of the Ch3C(O)O-2+no Reaction Using Chemical-Ionization Mass-Spectrometry
A direct measurement of the CH3C(O)O-2 + NO gas-phase reaction rate coefficient over the temperature range 200-402 K was made using chemical ionization mass spectrometric detection of the CH3C(O)O-2 reactant. A significant temperature dependence was observed, and a temperature dependent expression of k(T) = (8.1 +/- 1.3) x 10(-12) exp{(270 +/- 60)/T} cm(3) molecule(-1) s(-1) was determined. The 298 K rate coefficient, k = (2.0 +/- 0.3) x 10(-11) cm(3) molecule(-1) s(-1), agrees well with results from previous indirect measurements. NO2, CH3, and CO2 were positively identified as products originating from the reaction. The question of whether CH3 and CO2 are direct products of the reaction or result from the thermal decomposition of CH3C(O)O could not be answered, The 298 K rate coefficients for the reactions of SF6-, I-, and O-3(-) with CH3C(O)O-2 were measured to be (7(-2)(+4)) x 10(-10), (9(-5)(+7)) x 10(-10), and greater than or equal to 2 x 10(-10) cm(3) molecule(-1) s(-1), respectively.