V2O5/SBA-15 nanocatalysts for the selective synthesis of 2,3,5-trimethyl-1,4-benzoquinone at room temperature

Abstract

A series of four V₂O₅/SBA-15 catalysts with the loadings of 5, 7.5, 10 and 12.5% (by weight) V₂O₅ have been prepared by the molecular designed dispersion (MDD) method and are characterized by N₂-physisorption, low-angle and wide-angle XRD, transmission electron microscopy (TEM), Fourier Transform-Raman spectroscopy (FT-Raman), Ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis, DRS), temperature programmed reduction (TPR) and inductively coupled plasma-optical emission spectrometry (ICP-OES) techniques. Among V₂O₅/SBA-15 catalysts, the 10%V₂O₅/SBA-15 catalyst exhibited 99% 2,3,5-trimethylphenol (TMP) conversion with 95% 2,3,5-trimethyl-1,4-benzoquinone (TMBQ) yield when H₂O₂ (30% aqueous solution) and ethanol were used as green oxidant and green solvent respectively at room temperature. The remarkable activity of the 10%V₂O₅/SBA-15 catalyst is due to the isolated distribution of uniform sized nanovanadium species on the pore surfaces of the hexagonally ordered mesoporous SBA-15 silica support.