Directly synthesized V-containing BEA zeolite: Acid-oxidation bifunctional catalyst enhancing C-alkylation selectivity in liquid-phase methylation of phenol

V-containing BEA zeolite (Vβ) with the V/Si molar ratio of 1‰ was hydrothermally synthesized and fully characterized. It delivered the tetrahedral, highly isolated atomically dispersed V species owning the intermediate covalence state between +4 and +5 (closer to +5) within zeolite matrix, endowing oxidation capability without compromising acidity. In the low-temperature liquid-phase methylation of phenol with methanol, Vβ showed high yield (turnover number up to 5946), good reusability and preferential chemoselectivity towards the C-alkylation products (o- and p-cresols). In situ FTIR spectra suggested an acid-oxidation bifunctional mechanism involving the oxidative activation of methanol via formaldehyde. Moreover, alkylation of phenol with various other alcohols was also efficiently catalyzed by Vβ, wherein the large-sized alkylation agency showed special regioselectivity. This work not only achieves selective production of cresols through methylation of phenol at low temperature, but highlights the potential of designing high performance heterogeneous catalyst with highly dispersed active sites via controlling the chemical composition of heteroatom zeolite.