Pore Morphological Control Of Mesoporous Organosilica Impregnated Polyoxometalates Composites Materials For Oxidation Of Alkenes

The heteropoly acid has been the research trend of modern catalyst, which has both acidity and redox activity. However, the heteropoly acid often suffers from difficulty in recovery because of being soluble in polar solvents, and has the small specific surface area, which limited its many practical applications in the process of catalytic. Therefore, the heterogenization of heteropoly acid is effective way to overcome the limitation and get better catalytic properties by supported in the mesoporous materials that have large specific surface area, large pore diameter and high entrance. This paper is dedicated to design and prepare a series of mesoporous structured H3PW12O40/SBA-15 and H3PW12O40/PMO using silica or organic silicon oxide as support. The catalytic performance heterogeneous catalysts were studied through the oxidation of styrene to prepare benzaldehyde. The concrete research contents are as follows.Mesoporous structured H3PW12O40SBA-15 are prepared with different phosphotungstic acid loading amount (8.9-15.7%) and controlled two-dimensional pore structure by the one-step sol-gel condensation method using three block copolymer P123 as template. The composition, structure, surface morphology characterization and physicochemical properties of composite materials were characterized by XRD, FT-IR, TEM and N2 adsorption. The results indicated that the prepared composites have high BET surface area, and the dispersed Keggin unit of heteropoly acid evenly throughout the materials. We studied the catalytic oxidation properties of H3PW12O40/SBA-15 composite materials by the oxidation of styrene, and the reusability of the catalysts was evaluated.Mesoporous structured H3PW12O40/SBA-15 are prepared with different phosphotungstic acid loading amount(14.8-28.5%) and controlled two-dimensional pore structure by the one-step sol-gel condensation method using three block copolymer P123 as template, organic silicon as support and polyoxometalate as active species. The composition, structure, surface morphology characterization and physicochemical properties of the prepared composite materials were characterizied by XRD, FT-IR, TEM and N2 adsorption methods. The results indicated that the H3PW12O40/PMO catalysts presented larger BET specific surface area, and the Keggin unit evenly dispersed in the organic silicon material. The catalytic oxidation properties of composite materials H3PW12O40/PMO were studied by the catalytic oxidation of styrene, and the reusability of the catalysts was evaluated, which lay a foundation for its practical application.