Kinetics of Several Oxygen-Containing Carbon-Centered Free Radical Reactions with Nitric Oxide

Abstract

Kinetics of four carbon-centered, oxygen-containing free radical reactions with nitric oxide (NO) were investigated as a function of temperature at a few Torr pressure of helium, employing flow tube reactors coupled to a laser-photolysis/resonance-gas-discharge-lamp photoionization mass spectrometer (LP-RPIMS). Rate coefficients were directly determined from radical (R) decay signals under pseudo-first-order conditions ([R]0 ≪ [NO]). The obtained rate coefficients showed negative temperature dependences, typical for a radical-radical association process, and can be represented by the following parametrizations (all in units of cm(3) molecule(-1) s(-1)): k(CH2OH + NO) = (4.76 × 10(-21)) × (T/300 K)(15.92) × exp[50700/(RT)] (T = 266-363 K, p = 0.79-3.44 Torr); k(CH3CHOH + NO) = (1.27 × 10(-16)) × (T/300 K)(6.81) × exp[28700/(RT)] (T = 241-363 K, p = 0.52-3.43 Torr); k(CH3OCH2 + NO) = (3.58 ± 0.12) × 10(-12) × (T/300 K)(-3.17±0.14) (T = 221-363 K, p = 0.50-0.80 Torr); k(T)3 = 9.62 × 10(-11) × (T/300 K)(-5.99) × exp[-7100/(RT)] (T = 221-473 K, p = 1.41-2.95 Torr), with the uncertainties given as standard errors of the fits and the overall uncertainties estimated as ±20%. The rate of CH3OCH2 + NO reaction was measured in two density ranges due to its observed considerable pressure dependence, which was not found in the studied hydroxyalkyl reactions. In addition, the CH3CO + NO rate coefficient was determined at two temperatures resulting in k298K(CH3CO + NO) = (5.6 ± 2.8) × 10(-13) cm(3) molecule(-1) s(-1). No products were found during these experiments, reasons for which are briefly discussed.

Kinetic Study and Rate Coefficient Calculations of the Reaction of 1-Hydroxyethyl Radical with Nitric Oxide

“…Figure shows the calculated total rate coefficient k tot ( k tot = k Rw1 + k Rw2 + k Rw3 + k Rw4 + k Rw5 + k Rp1 ) in the temperature range of 241–363 K and at a pressure of 3.0 Torr along with the reference data. , Although k tot is underestimated at a temperature less than 260 K, it is very close to the limiting high-pressure rate coefficient illustrated in Figure . Considering the overall uncertainty of ±20% of the fit, k tot agrees well with the reference data.…”

“…38 Figure 2 shows the calculated total rate coefficient k tot (k tot = k Rw1 + k Rw2 + k Rw3 + k Rw4 + k Rw5 + k Rp1 ) in the temperature range of 241−363 K and at a pressure of 3.0 Torr along with the reference data. 12,13 Although k tot is underestimated at a temperature less than 260 K, it is very close to the limiting 12,13 The dashed lines indicate the variation of the fit of experimental data between these limits. 13 The Journal of Physical Chemistry A high-pressure rate coefficient illustrated in Figure 3.…”

“…12,13 Although k tot is underestimated at a temperature less than 260 K, it is very close to the limiting 12,13 The dashed lines indicate the variation of the fit of experimental data between these limits. 13 The Journal of Physical Chemistry A high-pressure rate coefficient illustrated in Figure 3. Considering the overall uncertainty of ±20% of the fit, 13 k tot agrees well with the reference data.…”

“…12 Rissanen et al investigated the kinetics of this reaction in the temperature range 241−363 K at the pressure of a few torr in helium. 13 Up to now, no theoretical data are available for the mechanism and kinetics of this reaction.…”

Atmospheric chemical reaction mechanism and kinetics of 1,2-bis(2,4,6-tribromophenoxy)ethane initiated by OH radical: a computational study

“…The reaction rate constant for the reaction of IM3 with NO is assumed in the order of 10 À14 cm 3 per molecule per s based on the reaction of typical aromatic-OH adducts with NO, 59 and IM7-1 + NO in the order of 10 À12 cm 3 per molecule per s based on the reaction rate constant of $CH 2 OCH 3 with NO. 60 In addition, to evaluate nal yield of products, a comprehensive product branching ratio was determined by calculating the product of branching ratio of IM3 and IM7-1 in the $OH initiated reaction and branching ratio of products of their subsequent reactions, respectively. The rate constants of all pathways and the comprehensive product branching ratio were listed in Table S3 † and Fig.…”