Papers by Keyword: Heteropolyacid

Abstract: We report the thermal and catalytic decomposition of low density polyethylene (LDPE) as a recycling route of plastic solid waste. The reaction system consisted of a fixed-bed reactor at a 450 °C reaction temperature and a 40 min reaction time. Tungstophosphoric acid (H3PW12O40)-functionalized ordered mesoporous materials MCM-41 were employed as catalysts. Results show that using this technical approach, on one hand, environmentally unfriendly waste can be disposed and, on the other hand, valuable and widely used fuels can be obtained.

Abstract: CexTi1-xO2 and H3PW12O40/CexTi1-xO2 catalysts were prepared by sol-gel method, and they were applied to the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide in a batch reactor. The reaction was carried out in an autoclave reactor at 170oC and 5 MPa. It was found that CexTi1-xO2 exhibited a higher catalytic performance than pure CeO2 and TiO2. The catalytic performance of CexTi1-xO2 was the maximum when x=0.1. It was also revealed that H3PW12O40/CexTi1-xO2 catalysts showed a remarkably enhanced catalytic performance than the corresponding CexTi1-xO2 catalysts. The amount of DMC produced by 15 wt% H3PW12O40/ Ce0.1Ti0.9O2 catalyst was six times higher than that produced by Ce0.1Ti0.9O2 catalyst. It is concluded that both Brönsted acid sites provided by H3PW12O40 and base sites in CexTi1-xO2 played an important role in improving the catalytic performance of H3PW12O40/CexTi1-xO2.

Abstract: Mesostructured cellular foam (MCF) silica was synthesized via surfactant templating route. The surface of MCF silica was then modified by grafting 3-aminopropyl-triethoxysilane (APTES) to have the positive charge, and thus, to provide sites for the immobilization of H3PMo12O40 (PMo12). By taking advantage of the overall negative charge of [PMo12O40]3-, PMo12 catalyst was chemically immobilized on the amine-functional group of surface modified MCF (SM-MCF) silica as a charge matching component. It was found that pore structure of MCF silica was maintained even after the surface modification and the subsequent immobilization of PMo12. It was also revealed that PMo12 species were finely and molecularly dispersed on the SM-MCF silica via chemical immobilization.