Kinetics and mechanism of the OH + C₆H₆ reaction: A detailed analysis with first-principles calculations

The capability of various high-level DFT and ab initio MO methods to predict molecular and energetic parameters has been critically tested for the OH radical reaction with benzene. G3 theory proved to be the most accurate in estimating reaction barriers and enthalpies. For the first time, the molecular structure, stabilization energy and nature of the bonding interactions of the [C₆H₆⋯OH] prereaction complex have been characterized. Accurate thermochemistry for major reaction channels was established by making combined use of experimental and theoretical parameters. A multistep kinetic model for the OH-addition channel was proposed, and the effects of T, P, and reaction time on the apparent rate constants were evaluated by weak collision master equation/RRKM analysis. Available experimental kinetic data for all relevant reactions are critically analyzed and correlated with modeled effective rate constants.