Keplerate-Type Polyoxometalate Anchored on HKUST-1 Derivatives as a Robust Heterogeneous Catalyst for Synthesis of 2,3,6-Trimethyl-1,4-benzoquinone

Functionalized benzoquinones (p-BQs) are essential intermediates in biomedicine and fine chemical synthesis due to their structural diversity and broad chemical reactivity. The development of highly efficient heterogeneous catalysts for their selective production is therefore of considerable importance. In this work, we report a new heterogeneous catalyst, Mo₇₂V₃₀/CuOx/C, prepared by immobilizing a V-substituted Keplerate-type polyoxometalate (POM), Na₈K₁₆(VO)(H₂O)₅[K₁₀⊂{(Mo)Mo₅O₂₁(H₂O)₃(SO₄₎}₁₂(VO)₃₀(H₂O)₂₀]·150H₂O (Mo₇₂V₃₀), onto a HKUST-1-derived CuOx/C support. The Mo₇₂V₃₀/CuOx/C catalyst exhibited exceptional activity in the oxidation of 2,3,6-trimethylphenol (TMP), achieving a conversion of over 99% and a yield of 95.3% within only 2 min, while maintaining high performance over five consecutive cycles. Until now, this represents the highest catalytic efficiency reported to date for this transformation. The exceptional catalytic performance stems from the catalyst's high surface area with porous structure, which is beneficial for TMP adsorption and activation, and the strong synergy among its multiple active centers that boosts reaction activity. DFT calculations further elucidated a cooperative dual-active-center mechanism at the atomic level.