Synthesis Of Polyoxometalates Incorporated Into Mesoporous And Its Catalytic Oxidation Performance

The traditional hydrodesulfurization?HDS?technology can remove the small molecule sulfide compounds of the feed dramatically,but the effect of large sulfide molecules' removal is not ideal,especially the fused ring of sulfur-containing compounds.What's more,the reaction conditions of high temperature,high pressure and the presence of hydrogen result in the high investment of traditional HDS process.The oxidative desulfurization gets popular because of its mild reaction condition,low equipment costs,high effect of removing large sulfide compounds like thiophene derivatives and ultra deep desulfurization of oil products.The paper brings two polyoxometalates?POM?,which have different structure types and compositions,to the metal-organic framework MIL-101 channel in different combination ways,and prepares new type acid base composites.Moreover,the catalytic oxidative performance of composites gets examined in different conditions,which is aimed at diesel DBT desulfurization and styrene oxidation.The main contents are as follows:Firstly,the composites POMs@ MIL-101 are prepared by parceling the Sandwich POMs into the cage of MIL-101 in impregnation method,which regards MIL-101 as support and POM as guest.And POMs@ MIL-101 are characterized and analyzed by XRD,IR,SEM,TG and BET methods.Results show that the support and guest of the composites both keep their whole crystal structures and the Sandwich POMs disperse homogeneously in the channel of MIL-101 without arrogation phenomenon.In addition,the paper examines the relationship between the heteropolyacid contents in impregnation liquid and heteropolyacid load contents in the composites,and finds that there is the maximum capacity,which means 100 mg MIL-101 can take up to 17 mg Sandwich POMs at most.By structure analyzing and calculating,when adsorption is saturated,there is only one Sandwich POMs molecule in every MIL-101 big cage and there are no ones in small cages,which realizes the single guest molecule's dispersion on the cellular materials successfully.Secondly,another composites H₃PW₁₂O₄₀@MIL-101 with staged pore structure are prepared by ?ship around bottle? method,which parcels H₃PW₁₂O₄₀ into the cages of MIL-101.The characterization results show that H₃PW₁₂O₄₀ can not only enters the MIL-101 channels but disperses homogeneously in them,which improves the dispersion effect and mass transfer of reactants and products on the catalysts.Finally,the catalytic oxidative performances of above two composites are researched under different conditions,which used styrene and simulated diesel containing 500 ppm DBT as the reactants.The results show that these two composites both can remove DBT of the simulated diesel effectively.On the other hand,the catalysts performances get comprehensive evaluation and analysis on the basis of styrene conversion,benzaldehyde selectivity,catalyst recyclability and so on.