Theoretical and experimental studies on mechanism and rate constant for the Baeyer-Villiger oxidation of cyclohexanone by H2O2 in phenol

The mechanisms for uncatalyzed and phenol-catalyzed Baeyer-Villiger oxidation of cyclohexanone by H2O2 have been investigated using density functional theory (B3LYP) with 6-31+G(d,p) basis set. The theoretical results indicate that the B-V oxidation can be activated by forming hydrogen bound complexes between phenol and reactants. The studied B-V oxidation proceeds in a two-step concerted mechanism, and the rearrangement step is rate-determining. The lower activation barriers in mechanism (e) proved that phenol activates both H2O2 and cyclohexanone is the most feasible mechanism. The apparent rate constants are positive temperature dependent at the range of 293.15-343.15 K. When the reaction rate is independent on the concentration of H2O2, the calculated rate constant (1.82 × 10−5 s−1) at 323.15 K and 1 atm is acceptable agreement with the experimental result (2.99 × 10−6 s−1).