Comparative Study of the Acidic and Catalytic Properties of the Mesoporous Material H-MCM-41 and Zeolite H-Y

Abstract

The objective of this work is to give a comparative characterization of aluminosilicate MCM-41 and zeolite Y, in particular with respect to acidity and catalytic properties in hydrocarbon cracking. These studies are compared to a well investigated amorphous aluminosilicate, based on the fact that the new mesoporous MCM-41 materials are a mixture of ordered material with amorphous pore walls. Characterization of differently treated MCM-41 materials and zeolite Y for comparison by N 2 sorption, XRD, TPAD (Temperature Programmed Ammonia Desorption) with in situ FT-IR in combination with catalytic testing by MAT (Micro Activity Test) is discussed. Combination of the characterization data and the catalytic testing gives an interesting explanation of the surface properties especially in comparison with zeolite Y.

Improved Brønsted Acidity of Mesoporous [Al]MCM-41 Material Treated with Ammonium Fluoride

“…Unlike zeolites, aluminum containing mesoporous MCM-41 materials ([Al]MCM-41) have a weak Brønsted acidity only. − The activity of [Al]MCM-41 for reactions catalyzed by Brønsted acid sites, e.g., n -heptane cracking, is much lower than that of zeolites H−Y and USY, but similar to that of amorphous silica−alumina . On the other hand, [Al]MCM-41 is reported as a suitable catalyst for the conversions of 1,3,5-triisopropylbenzene and cumene, which proceed predominantly via catalytic cracking . The incorporation of other trivalent elements, such as B, Ga, and Fe, leads to materials with lower catalytic activity than that of [Al]MCM-41 …”

Photodecomposition of Chloroform Catalyzed by Unmodified MCM‐41 Mesoporous Silica

“…Mesoporous silica has been widely used as a support for a variety of catalysts (1)(2)(3)(4); catalytic activity most often being achieved either by adsorbing a catalytic species on the silica surface (5)(6)(7)(8) or by incorporating one or more metal oxides during the synthesis of the mesoporous silica (9)(10)(11). Mesoporous silica has also been extensively used for photocatalytic reactions (12,13), in some cases unmodified, except for activation at high temperature (14)(15)(16)(17)(18)(19)(20)(21), but quite often by supporting the actual catalytic species (22)(23)(24)(25)(26) or by modifying the silica matrix (27,28).…”