Liquid phase hydroxylation of benzene to phenol over vanadyl acetylacetonate supported on amine functionalized SBA-15

An efficient catalyst for the direct hydroxylation of benzene to phenol with oxygen as the oxidant was developed by immobilizing the homogeneous vanadyl(IV) acetylacetonate (VO(acac)₂) on SBA-15 in which the support surface was functionalized by (3-aminopropyl)triethoxysilane. The as-prepared catalyst was characterized by various techniques including field-emission scanning electron microscopy, X-ray diffraction, nitrogen adsorption and desorption, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results show that the homogeneous vanadium species can be successfully immobilized on the amine functionalized SBA-15 and exhibits better catalytic performance in the hydroxylation of benzene with oxygen compared to other catalysts reported in the literature. The phenol yield significantly depends on the reaction conditions. Under the optimized reaction conditions, the phenol yield can reach 13.3 %, and the as-fabricated V/NH₂-SBA-15 shows better stability against leaching owning to strong interaction between vanadium atoms and amine group as compared to the V/SBA-15 sample.