CH₃ + O₂ → Η₂CO + OH Revisited

Abstract

New reflected shock tube kinetics experiments have been performed on the reaction CH(3) + O(2) --> H(2)CO + OH over the temperature range 1244-1502 K. This study was carried out using a White cell multipass (path length = 7 m) optical system observing OH-radical absorption at 308 nm. Within experimental error, the new results are in excellent agreement with an earlier study from this laboratory and have therefore been combined with the earlier data, yielding an updated Arrhenius description for the rate constant, k = (1.06 +/- 0.32) x 10(-12) exp(-6801 +/- 439 K/T) cm(3) molecule(-1) s(-1). This result is compared to earlier determinations, evaluations, and theory.

High temperature rate constants for OH+ alkanes

“…The OH optical absorption system consists of an OH resonance lamp, multi-pass reflectors, an interference filter at 308 nm, and a photomultiplier tube (1P28) all mounted external to the shock tube as described previously [19][20][21]. The OH resonance radiation is collimated to $1 mm with a set of lenses and is then focused onto the split mirror on the opposite side of the shock tube through the two AR coated windows that were flush mounted to the inside of the shock tube.…”

“…1. We used a previously presented mechanism [20,21] with additions that include both alkane abstractions by OH, alkane decompositions, and subsequent reactions; i.e., in the case of neo-pentane, C 5 H 12 + OH ? C 5 H 11 + H 2 O and C 5 H 12 (+M) ?…”

Shock tube measurements of high temperature rate constants for OH with cycloalkanes and methylcycloalkanes

“…The OH source molecule was tert-butyl hydroperoxide (tBH). tBH was obtained from Sigma Aldrich as a water solution (T-HYDRO tBH, ∼70% tBH by weight; i.e., ∼32 mol% tBH and 68 mol% H 2 O) and used as the OH-radical source for the OH + hydrocarbon reaction studies as described previously [19,20]. The gas mixtures were accurately prepared from pressure measurements using a Baratron capacitance manometer and were stored in 22 l glass bulbs in an all glass vacuum line.…”

“…(24) derived from the sum of Eqs. (18) and (19). There is only one tertiary abstraction site yielding MCP(rad4) + H 2 O, and its rate constant is given by Eq.…”

Experimental and kinetic modeling study of the oxy-fuel oxidation of natural gas, CH4 and C2H6

“…It has been extensively studied and the rate constant values from Srinivasan and co-workers for both product channels, CH 2 O + O 2 (R5) [38] and CH 3 O + O (R6) [39] are used, whereas the stabilization of CH 3 O 2 is not expected at the present conditions.…”