Designation Of Polyoxometalates On Catalytic Oxidation

Polyoxometalates (Polyoxometalates, POMs) is a metal oxide cluster compounds which exhibit similar characteristics as metal oxide. It is widely used in organic synthesis oxidation, light or air to degradate of air pollutants in the water. In recent years, finding efficient, highly selective POMs oxidation catalyst to activate molecular oxygen and hydrogen peroxide to achieve oxidative conversion of organic matter has been an important area for researchers. In this thesis, we controlled strong redox properties of POMs compounds and applied in biomass such as starch oxidation and air oxidation desulfurization reaction. It is a certain promotion using POMs on biomass oxidation and O2 oxidizing desulfurization. The research was carried out as follows:1. (NH4)5H6PV8Mo4O40(NPVMo) with redox was synthesized and characterized by IR, XRD,31PNMR and so on. Using NPVMo as catalyst was studied the activity in starch oxidation. By controlling the amount of catalyst, water usage, hydrogen peroxide, reaction time and reaction temperature in starch oxidation to define optimal reaction conditions. The results are as follows:starch 1 g,70?,2.5 mL (30%) hydrogen peroxide,1.0 mL water,0.1 mL 0.0001 wt% catalyst react for 10 h, the carboxylic acid can be prepared up to 0.648 mol/100 g of oxidized starch and the catalyst can be reused.2. Using ionic liquids as precursor combine with POMs to form a new series of catalysts [(CH3)3NCH2CH2OH]xNa5-xIMo6O24 (ChxNa5-xIMo6O24 x=1-5). They were characterized by IR, UV, XPS to define the composition and structure and applied to the catalytic oxidation of dibenzothiophene (DBT), benzothiophene (BT), 4,6-dimethyldibenzothiophene (4,6-DMDBT). By regulating the reaction time, temperature, amount of catalyst in the desulfurization, using 0.1 mmol CI15IMO6O24 as catalyst,100 ? to react 8 h the conversion was close to 100%. The reaction mechanism was studied at the same time. Since the introduction of choline ions the catalyst performed well on enriching substrate to promote the catalytic reaction. Meanwhile, polyoxometalate anion can activate molecular oxygen, so that the synergy of both higher performance Gh5IMO6O24 oxidative desulfurization activity3. Design and Synthesis functional POMs immobilized on ceria catalyst NPVMo@CeO2 and as a catalyst for redox reaction. The catalyst was characterized by IR, BET, XRD, TEM and so on. By regulating the reaction time, temperature, the amount of catalyst in the desulfurization to determine the best conditions. While using 200 mg NPVMo@CeO2-9.3 as catalyst in 6 mL decalin with 500 ppm DBT,100 ?,6 h the conversion of DBT and 4.6-DMDBT was close to 100% and the conversion of BT was 92%. After the reaction, the catalyst can be reused several times with no activity decreasing.