Zeolite Beta BEA

Zeolite beta ( Na2 [Al7Si570i2s]) has a three-dimensional network of 12-ring pores, which could be presented by a short notation of 100 12 6.6 x 6.7 - [001] 12 5.6 x 5.6. The unit cell of BEA structure is tetragonal (a = 12.661, c = 26.406 A) with PA 22 symmetry. 

Zeolite beta has been widely used in the petroleum refining and fine chemical industries due to its high thermal stability and strong acidity. Like LTA-, FAU-, MOR-, and MFI-type molecular sieves, zeolite beta molecular sieve has been industrially produced for a long time. The laboratory synthetic procedure described here was developed by M.A. Camblor and J. Perez-Pariente.[128] Tetraethylammonium hydroxide (Alfa 40 wt% TEAOH), sodium chloride, potassium chloride, silica, sodium hydroxide, sodium aluminate, and deionized water were used to prepare the reaction gel with a composition of 1.97 Na20 1.00 K20 12.5 (TEA)20 A1203 50 Si02 750 H20 2.9 HC1. The detailed procedure for the preparation of 20 g of anhydrous product is described below  

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The vapour-phase transport method was also successfully used for the preparation of membranes and bulk material of the following zeolites MCM-22 membrane (used for the alkylation of toluene with MeOH to p-xylene),[68] FER-membrane (for the separation of benzene/p-xylene),[69] EMT crystals using a crown ether as structure-directing agent,[70] and zeolite beta (BEA).[71] In the latter two examples, a conversion of agglomerated nanoparticles to highly crystalline zeolite was observed. 

Creyghton et al. recently reported the application of zeolite Beta (BEA topology) in the stereoselective (> 95%) reduction of 4-tert-butylcyclohexanone to cw-4-fert-butylcyclohexanol in the liquid phase [23,24]. This zeolite-based catalyst proved to be fully regenerable without loss of activity or stereoselectivity. This is of industrial relevance, because the cis isomer is a fragrance-chemical intermediate. Other active solid catalysts, including zeolites, invariably gave the thermodynamically more stable tj-ans isomer in excess. 

Figure 10.1 Partial structures of several important zeolites, clockwise from top left faujasite (FAU), linde type A (LTA), zeolite beta (BEA ), and zeolite ZSM-5 (MFI). (See Reference 7.)...

It is thought that the zeolite seed solution may contain the zeolite building units such as secondary building units (SBUs), which play a potential structure-directing role in the crystallization of zeolite crystals. The introduction of seed crystals into the starting aluminosilicate gels is considered to be an efficient way to accelerate the crystallization rate of zeolites. A typical example is shown by the aluminosilicate zeolite Beta ( BEA). In 2008,... 

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