Acidic and cesium salts of polyoxometalates with and without vanadium supported on MCM-41 as catalysts for oxidation of cyclohexane with H2O2

Abstract

Acidic and cesium salts of polyoxometalate (POM) with and without vanadium supported on MCM-41 were synthesized and their catalytic activities were investigated in the oxidation of cyclohexane with H 2 O 2 under solvent-free condition. The products are cyclohexanol and cyclohexanone. The catalytic activity order is: CsV-POM/MCM [ HVPOM/MCM [ CsPOM/MCM * HPOM/ MCM [ CsVPOM [ CsPOM catalysts. High conversion and selectivity to cyclohexanone over the supported catalysts are due to redox property and high surface area. These heterogeneous catalysts can be reused.

A green and reusable catalytic system based on silicopolyoxotungstovanadates incorporated in a polymeric material for the selective oxidation of sulfides to sulfones

“…The XRD diagrams obtained for SPH-SPOV samples do not display the characteristic diffraction lines of SiPV1 and SiPV2, being similar to the XRD pattern of the SPH. From these results, it can be inferred that SPOV is highly dispersed into the sample or as a noncrystalline phases (data not shown) [45,46]. This is in agreement with EDX mapping images of W element in the SPH-SPOV samples (Figure S1) that shows its overall homogeneous distribution.…”

Catalytic Conversion of Biomass into Hydrocarbons over Noble‐Metal‐Free VO‐Substituted Potassium Salt of Phosphotungstic Acid

“…The BET surface area and pore volume of K[VO(H 2 O) 5 ][PW 12 O 40 ]•6H 2 O were measured to be 0.968 m 2 /g and 2.257×10 −3 cm 3 /g, respectively, while K 3 [PW 12 O 40 ] sample possesses the BET surface area of 0.576 m 2 /g and 1.725×10 −3 cm 3 /g. The introduction of [VO] 2+ as counter‐cations in phosphotungstic acid increases the surface area and pore volume as compared to K 3 [PW 12 O 40 ] . The total acidity of K[VO(H 2 O) 5 ][PW 12 O 40 ]•6H 2 O and K 3 [PW 12 O 40 ] was measured to be 197.5 μmol g −1 and 162.9 μmol g −1 respectively by NH 3 ‐TPD (Figure ).…”

Extractive-catalytic oxidative desulfurization of a model fuel over vanadium-containing heteropolyacids immobilized on amine-functionalized magnetic graphene oxide: a comparative study between Keggin and Dawson-type heteropolyacids and process optimization via response surface methodology

“…This phenomenon may be ascribed to the fact that the redox potential of Mo-based HPAs increases with the V atom incorporation into its structure. 77 In other words, substituting V 5+ with Mo 6+ leads to more reactive lattice oxygen. 78…”