Role in zeolite synthesis

From the time of the mixing of the starting materials to the moment of zeolite application, seve processes may occur all of which may contribute to the formation of the final product. In the majority of zeolite formation processes, the synthesis involves the formation of a gel phase. Investigations of the precrystalline gel phase have shown that the chemical composition of this phase resembles the composition of the final zeolite structure (Zhdanov 1971). As such, zeolite X could, for instance, be directly synthesized by treatment of the solid, precrystalline phase of the initid reaction mixture (Breck 1974). Formation of the alumino-silica gel thus must play a crucial role in zeolite synthesis. 

Lowe BM, MacGUp NA, Whittam TV (1980) Active silicates and their role in zeolite synthesis. In Rees LVC (ed) Proceedings of the 5th international conference on zeolites. 

Quaternary ammonium bromides play an important role in the synthesis of high silica zeolites... 

Synthesis of silica-based materials with controlled skeleton structures, such as zeolites, requires controlling the structure of oligomeric silicate species at the first reaction step. Organic quaternary ammonium ions, which are known as organic templates in zeolite synthesis (1 ), have a role in making up the specific structures of silicate anions, whereas silicate anions randomly polymerize in aqueous solutions containing alkali metal ions, resulting in the presence of silicate anions with different structures. 

We are interested in the role of organic ions and organic molecules in zeolite synthesis. The use of organic molecules in zeolite synthesis mixtures in addition to inorganic bases is known to result in the medium-pore-size low-aluminum-content zeolites, such as ZSM-5, that revolutionized several processes of importance to the oil-refining and petrochemical industry. 

The role of organic templates in zeolite synthesis has been studied extensively, but no general principles have been delineated. 

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