Protons Make Possible Heterolytic Activation of Hydrogen Peroxide over Zr-Based Metal–Organic Frameworks

The catalytic performance of zirconium-based metal–organic frameworks (UiO-66, UiO-67, and MOF-801) in cyclohexene oxidation with aqueous hydrogen peroxide can be greatly improved by adding a source of protons directly into the reaction mixture. A blend of Zr-MOF and protons favors heterolytic activation of H₂O₂ and makes possible selective formation of epoxide and diol with negligible formation of allylic oxidation products. Additives of HClO₄ suppress the rates of H₂O₂ decomposition over Zr-MOF and increase oxidant utilization efficiency. No structural changes occur in the acid-activated Zr-MOF. The catalyst does not suffer metal leaching, reveals a truly heterogeneous nature of the catalysis, and can be recovered and reused.