Special Synthesis Approaches and Recent Progress

5 Special Synthesis Approaches and Recent Progress Secondary Synthesis of Microporous Materials 

Nearly all syntheses of zeolites and microporous aluminophosphates have limitations to gel composition and other parameters. For example, some zeolites with special compositions such as high-silica Y zeolite and low-silica ZSM-5 cannot be directly synthesized. A secondary framework modification is necessary for their preparation. For instance, dealuminization, isomorphous substitution of extraneous silicon for aluminum, and removal of the sodium process in Y zeolite are necessary to prepare ultra-stable zeolite Y (USY) isomorphous replacement of framework atoms of boron with aluminum in a presynthesized silicon-boron structure is often used to prepare some specific aluminosilicate zeolites that cannot be directly synthesized, such as Al-SSZ-24 (AFI) and Al-CIT-1. Secondary synthesis (post-treatment) will be discussed in detail in Chapter 6. 

IZA code Type of microporous compound Composition Template Location of F 

CHA AIPO [AI6P6O24F][C4H10NO] morpholine bridge in 4MR atom, 

CIS AIPO [AI2P208F][NH2Me2] Me2NH bridge in 4MR atom, 

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