Baeyer–Villiger and Epoxidation Reactions of Dihydrocarvone using Hydrogen Peroxide over Sn‐, Ti‐, Zr‐, and Hf‐Beta Zeolites: A DFT Study

The Baeyer–Villiger and epoxidation reactions of dihydrocarvone with hydrogen peroxide over zeolite catalysts is investigated using the M06‐L density functional theory. The Baeyer–Villiger reaction over 38T quantum clusters of Sn‐, Ti‐, Zr‐, and Hf‐beta zeolites is thought to proceed via a two‐step mechanism with apparent activation energies of 5.3, 18.1, −1.3, and −0.9 kcal/mol and energy spans of 33.6, 40.1, 31.1, and 34.8 kcal/mol, respectively. The calculated activation energies of competitive epoxidation reactions over Sn‐, Ti‐, Zr‐, and Hf‐beta zeolites are 11.2, 16.2, 16.4, and 15.0 kcal/mol, respectively. The Sn‐beta zeolite selectively afforded the lactone product owing to the formation of thermodynamically favored adsorption and product complexes and the lower apparent activation energy of the Baeyer–Villiger reaction. Zr‐beta and Hf‐beta zeolites are thought to be selective catalysts toward Baeyer–Villiger oxidation. Reactions without zeolites are also studied over m‐chloroperbenzoic acid. The epoxidation is favored over the Baeyer–Villiger reaction owing to its lower activation energy (16.6 kcal/mol vs. 39.4 kcal/mol). The catalytic activity and chemoselectivity are studied using various Lewis acid zeolite catalysts.