J.A. Wang

Framework modification and acidity enhancement of zirconium-containing mesoporous materials

Zirconium-modified mesoporous molecular sieves with different Si/Zr molar ratios were synthesized through a surfactant templating route. In situ FTIR characterization shows that surfactant strongly interacts with the solid matrix, and its complete removal could be achieved at 400 °C. The structural ordering, textural properties and surface acidity of the resultant materials vary with the Si/Zr molar ratio. The incorporation of zirconium greatly increases not only the number of both Lewis and Bronsted acid sites but also the acid strength.

Al-MCM-41 and Pt/H3PW12O40/Al-MCM-41: structure characterization and catalytic properties

Abstract The impregnation of H 3 PW 12 O 40 (referred as HPW) heteropolyacid on the Al-MCM-41 solid noticeably enhances by 2–3 times the Bronsted acidity with respect to the bare host. Catalytic evaluation confirms that 1wt %Pt/25wt.%HPW/Al-MCM-41 catalyst is active for n-heptane isomerization in the presence of hydrogen under atmospheric condition. The n-heptane conversion linearly increases with increasing the reaction temperature, while, the selectivity to isoheptanes gradually decreases. 2-methylhexane is predominant in the monobranched isomers and 2, 3 dimethylpentane is the prevailing compound more than 50 % in the multibranched isomer products. The molar ratio of multibranched to monobranched isoheptanes varies within a narrow range between 0.8 and 1.2, and this ratio is much higher than that reported in the literature at similar reaction conditions using zeolites containing catalysts.