Detailed Kinetics and Thermochemistry of C2H5 + O2: Reaction Kinetics of the Chemically-Activated and Stabilized CH3CH2OO• Adduct

The kinetics of the chemically activated reaction between the ethyl radical and molecular oxygen are analyzed using quantum Rice−Ramsperger−Kassel (QRRK) theory for k(E) with both a master equation analysis and a modified strong-collision approach to account for collisional deactivation. Thermodynamic properties of species and transition states are determined by ab initio methods at the G2 and CBS-Q//B3LYP/6-31G(d,p) levels of theory and isodesmic reaction analysis. Rate coefficients for reactions of the energized adducts are obtained from canonical transition state theory. The reaction of C2H5 with O2 forms an energized peroxy adduct with a calculated well depth of 35.3 kcal mol-1 at the CBS-Q//B3LYP/6-31G(d,p) level of theory. The calculated (VTST) high-pressure limit bimolecular addition reaction rate constant for C2H5 + O2 is 2.94 × 1013T-0.44. Predictions of the chemically activated branching ratios using both collisional deactivation models are similar. All of the product formation pathways of ethyl...