Linde type A

The nomenclature of zeolites is rather arbitrary and follows no obvious rules because every producer of synthetic zeolites uses his/her own acronyms for the materials. However, as mentioned before, at least the structure types of the different zeolites have a unique code. For example, FAU represents Faujasite-type zeolites, LTA Linde Type A zeolites, MFI Mobile Five, and BEA Zeolite Beta. The structure commission of the International Zeolite Association (IZA) is the committee granting the respective three-letter codes [4], Some typical zeolites, which are of importance as catalysts in petrochemistry, will be described in the following sections. 

Garcia-Sanchez, A., Garcia-Perez, E., Dubbeldam, D., Krishna, R., and Calero, S. (2007) A simulation study of alkanes in Linde type A zeolites. Adsorp. Sci. Technol, 25, 417-427. 

Synthesis and Crystal Structure of Zeolite Rho—A New Zeolite Related to Linde Type A... 

Figure 9.6 Topologies of zeolite structure types, (a) Sodalite (b) Linde type A (c) faujasite (zeolite X and Y) (d) AlP04-5 and (e) ZSM-5. The vertices represent the positions of AI04 or Si()4 letrahedra while straight lines represent Si-O-Si or Si-O-Al linkages. (Reproduced with permission from [5]).

The diversity of pore sizes coupled with the essentially cation-free framework make AlPOi, molecular sieves potentially applicable in separations of molecules and other adsorption applications. A broad screening program in air drying has shown many AlPOi, molecular sieves with performance characteristics similar to those of Linde Type A and X. The hydrophilic surface character has also been demonstrated in the selective removal of Hz0 from solutions of 2-butanone containing 4 vol.% HzO. The hydroxyl infrared region (4000-3400 cm-1) for several AlPO molecular sieves contains weak VqH absorptions at 3680 cm- attributed by Peri (14)... 

Three examples will suffice to demonstrate this information Figure 3 shows the polyhedral units in the synthetic zeolite Linde Type A, which link to provide a three-dimensional interconnecting array of channels, Figure 4 illustrates the essentially two-dimensional system of channels in the mordenite framework, and Figure 5 shows the major channels in synthetic zeolite Linde Type L arranged as parallel one-dimensional channels and shown as a stereo pair. Table 6 lists the Atlas notations for these structures with explanations, including the symbols used in Tables 2-5. 

ETA Linde Type A Nai2[Ali2Sii2048]-27H20 Alpha, LZ-215, N-A, ZK-4... 

Linde type A LTA 4.1 3 LZ-215 N-A Gallophosphate-A Sapo-42 Alpha Galloeermanate-A ZK-4 ZK-21 ZK-22... 

FIGURE 25.18 Main zeolite structures. SOD sodalite LTA Linde type A zeolite FAU faujasite, zeolites X or Y MOR mordenite LTL Linde type L zeolite MFI ZSM-5. (From Ozin, G.A., Kuperman, A., and Stein, A., Angew. Chem. Int. Ed. Engl., 28, 359, 1989.)... 

More than one hundred different zeotype structures, based on different topologies of the linkage of corner-sharing [TO4/2] tetrahedra (T = Al, Si, P. . . ), have been discovered so far. The various topologies are compiled in the "Zeolite Atlas" [21] under their respective three-letter code (e.g., LTA for "Linde Type A" or zeolite A, MFI for "ZSM-5" or "Mobil Five"). Apart from the framework composition, the high variability of framework structures is related to the fact that all of these compounds are metastable [14] and are formed by kinetic control under the influence of various SDAs. 

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