Theoretical study of mechanism and kinetics for the addition of hydroxyl radical to phenol

The reaction mechanism and kinetics for the addition of hydroxyl radical (OH) to phenol have been investigated using the hybrid density functional (B3LYP) method with the 6-311++G(2dp, 2df) basis set and the complete basis set (CBS) method using APNO basis sets, respectively. The equilibrium geometries, energies, and thermodynamics properties of all the stationary points along the addition reaction pathway are calculated. The rate constants and the branching ratios of each channel are evaluated using classical transition state theory (TST) in the temperature range of 210 to 360 K, to simulate temperatures in all parts of the troposphere. The ortho addition pathway is dominant and accounts for 99.8%–96.7% of the overall adduct products from 210 to 360 K. The calculated rate constants are in good agreement with existing experimental values. The addition reaction is irreversible.