Mesoporous V-AlPO – New Partial Oxidation Catalyst

<p>Vanadium incorporated hexagonal mesoporous aluminophosphate characteristic of MCM-41 has been synthesized. Characterization of the catalyst has been done by using low angle XRD, N₂ adsorption, UVVIS DRS, thermal analysis, XPS and ESR spectroscopy. These techniques confirm the presence of vanadium in both +4 and +5 oxidation states in the calcined material. Liquid phase partial oxidation of toluene has been carried out on V-AlPO using 70% TBHP and 30% H₂O₂ as oxidants. When 70% TBHP is used as an oxidant, it resulted in side chain oxidation giving rise to aldehyde/acid where as with 30% H₂O₂, side chain as well as ring oxidation takes place. Catalytic activity of V-AlPO has been compared with that of VMCM-48 and other vanadium containing catalytic systems. It has been observed that mesoporous V-AlPO shows higher conversion and is also selective towards side chain oxidation products. The higher conversion of V-AlPO over V-MCM-48 has been attributed to the stabilization of the active V^+5/+4 species in AlPO framework as compared to silicate analogue.</p>

Role of lattice oxygen in oxidative steam reforming of toluene as a tar model compound over Ni/La0.8Sr0.2AlO3 catalyst

High catalytic performance of Ni/La0.8Sr0.2AlO3 catalyst due to high amount of mobile lattice oxygen which favors direct partial oxidation of toluene while gas-phase oxygen favors complete oxidation. Both oxygen species actively oxidize coke deposited on catalyst surface, conferring coking resistance.

Synthesis and Catalytic Property of V-MCM-41 Mesoporous Molecular Sieves by Atrane Route

V-MCM-41 molecular sieve with high vanadium content has been prepared by the atrane route. Gas phase partial oxidation of toluene to benzaldehyde on the V-MCM-41 molecular sieves catalysts was studied. The structure and characteristic of catalyst were characterized by means of XRD, UV-vis and so on. The experimental results showed that the vanadium content in the framework related to mole ratio of silica to vanadium. The vanadium content in the framework was the highest, when the mole ratio of Si to V was 30. And the vanadium in the framework may be active centers of catalytic oxidation of toluene to benzaldehyde. Under the condition of atmospheric pressure, mole ratio of Si to V 30, space velocity 800 h-1, n(air):n(toluene)=5 and reaction temperature 450°C，the conversion of toluene, selectivity to benzaldehyde and its yield were 20.8%, 41.8% and 8.7% respectively.