Zeolite sigma

A. Pedone, M. Pavone, M.C. Menziani, V. Barone, Accurate first-principle prediction of Si and NMR parameters in Si02 polymorphs the cases of zeolites sigma-2 and ferrierite. J. Chem. Theory Comput. 4,2130-2140 (2008)... 

Table 4.4 Calculated VC Si—O— Si) Coupling Constants for Cluster Model of Zeolite Sigma-2"... 

Vinyl octanoate was obtained from TCI (Tokyo, Japan). All other chemicals with the exception of the zeolite beta are available from Sigma Aldrich. The synthesis of a particularly active modification of low-alumina zeolite beta has been described by us. Commercial material, available as samples from, for example, Zeolyst or Siidchemie can be used, but because of excessive acidity may result in up to 15 % of styrene formation. 

Although not by design, Balkus and coworkers have successfully synthesized the ZSM-48 - SSZ-31 - UTD-1 sigma expansion series by incrementally increasing the size of a cobaltocenium-derivatized structure-directing agent. They found that Cp2Co+ directs for ZSM-48, (MeCp)2Co+ directs for SSZ-31 and Cp 2Co+ directs for the 14 MR zeolite, UTD-1 [47]. 

Here, we have combined experimental information with computational modeling calculations to outline the design of a new, extra-large-pore, high-silica zeolite. The sigma expansion of the SSZ-48 structure to form the HYP-14 MR structure has been observed in the ZSM-48 - SSZ-31 - UTD-1 zeolite series synthesized from successively bulkier cobaltocenium derived... 

MOR ring opening catalyst MOR, sigma transformation MOR, synthesis MOR, structure modelling MOR, thermal stability MOR, vibrational spectroscopy MOR, in zeolitic tuff MOR, Zn... 

Precaution Flamm., corrosive Hazardous Decomp. Prods. CO, CO2, NOx Uses Intermediate for pharmaceuticals, fungicides, bactericides, agric., zeolites, resin crosslinking, dyes, ink, rubber chems., textile chems., corrosion inhibitors Manuf./Distrib. Aldrich http //www.sigma-aldrich.com, BASF http //www.basf.com, DuPont http //www.dupont.com, Fluka http //www.sigma-aldrich. com, M onomer-Polymer Dajac Labs Sigma... 

Zeolite ZSM-58 (and its coimterpart Sigma-1) have been foimd useful in the conversion of methanol to mainly lower olefins [16,18] and for the oligomerization of propylene [17]. Moreover, it has been shown that shape selective... 

So far, essentially two templates have been reported to promote the crystallization of materials with the DDR framework topology, viz. 1-aminoadamantane (ADA) and methyltropiniumiodide. Their structures are depicted in Fig. 1. Both are relatively bulky molecules which, after hydrothermal synthesis, are encapsulated inside the large cavities of the DDR structure and have to be removed by calcination in an oxygen-containing atmosphere at temperatures of at least 813 K. Materials which have been prepared using 1-aminoadamantane are denoted as deca-dodecasil 3R [20,22] or Sigma-1 [18], while zeolite ZSM-58 is prepared using methyltropiniumiodide [16,17,19]. 

Using the same UTL zeolite, Kirschhock and coworkers proposed the theoretical concept of inverse sigma transformation by removal of the germanium layer followed by calcination and generated a new zeolite structure experimentally (shown in Fig. 15) [132]. Since the D4R... 

Verheyen E, Joos L, Van Havenbergh K, Breynaert E, Kasian N, Gobechiya E, et al. Design of zeolite by inverse sigma transformation. Nat Mater 2012 11 1059-64. 

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