M41S materials, mesoporous molecular sieves

In 1992, Mobil reported a novel family of molecular sieves known as the M41S materials that established an entirely new area in nanoporous solids (168,169). The M41S materials expanded the range of pore sizes into the mesoporous domain (20-300 A). The impact of this discovery on molecular sieve research has been profound. In 1998, an international conference solely devoted to mesoporous molecular sieves was founded (170). The journal Microporous Materials even re-... 

Table 1 shows the structural properties of the titanium-incorporated mesoporous molecular sieves. The surface areas of all samples were over 750 m2/g, being typical of M41S group materials. After grafting, surface area and total pore volume decreased [8],... 

TTus paper is concerned with the particular class of molecular sieves having periodic mesoporous structure with pore sizes in the range of 2 to 10 nm. They are comprised of the M41S mesoporous molecular sieves and solids with related structures. In the first part, the preparation methods and characterization techniques will be reviewed and discussed. Silicate-based materials and non-silicate materials will be dealt with separately. In the second part of this review particular emphasis will be put on potential applications reported in both the patent and the open literature. Early progress in tWs field has been presented in the previous Summer School by Casci [37]. Potential catalytic applications of M41S were also reviewed rprPTitlv 1381... 

Mesoporous molecular sieves materials5-8 designated M41S (which include the MCM-41 class of materials) have made a further major impact on the area of synthesis of porous materials. A variety of open framework structures that are mesoporous have recently been reviewed by Thomas.9 Activated charcoal, MCM-41, mesoporous tungsten oxide, and substituted MCM-41 materials are mentioned. This article primarily emphasizes potential applications of such materials and possible mechanisms of reaction. The mesoporous sysems are compared briefly to microporous materials such as zeolites, ALPOs, MeALPOs and SAPOs. 

A new family of silicate/aluminosilicate mesoporous molecular sieves designated as M41S and kanemite were introduced a few years ago (39-43), and NMR investigations have been done to characterize those materials. 

The application of solvent extraction to removal and recovery of templates or SDAs from zeolite channels was initiated by Whitehurst[7] in the 1990s for the extraction of surfactant from mesoporous M41S materials. This method or its improved analogs have become one of the most important techniques to recover surfactants from mesoporous molecular sieves. However, it is still difficult to use this technique to remove and to recover the SDAs from microporous molecular sieves because, first, the size of SDA molecules is similar to that of the channel openings and the molecules are not able to diffuse out from the channels, and, secondly, there are usually strong interactions between the microporous frameworks and the SDA molecules that prevent the SDA molecules from being extracted solely by solvents. Modification of the conventional solvent-extraction technique, such as addition of chemical agents which can adjust the... 

The seareh for zeolitie materials with pore sizes larger than lOA recently resulted in a new class of materials termed mesoporous molecular sieves (known by the designation M41S), which are prepared using surfactant micelles as templating agents [17]. The pore diameter of these materials is tunable in a wide range of about 30 to lOOA but the matrix consists of amorphous rather than crystalline silica walls. Incorporation of hetero-atoms (Al,... 

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