Zeolites, large pore molecular sieves 24-membered ring structures

On the basis of these structural features, it is easy to understand why zeolites constructed by Si and A1 cannot have extra-large pores. Nevertheless, pure-silica zeolites with 14-membered rings, i.e. CIT-5 and UTD-1, have been synthesized recently, and further investigation into crystallization mechanisms in combination with the vast experimental data available and with theoretical simulation and computation may help us to rationally design and synthesize extra-large microporous aluminosilicate molecular sieves with special channels such as multidimensionally interconnected and chiral ones. 

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