Gallium-containing zeotype materials

The success of syntheses designed to incorporate gallium into zeotype frameworks depends on the synthesis conditions, as is true for other framework metal-containing zeotype materials. Several researchers have claimed gaUium incorporation into the frameworks of zeotype structures (5b, 166). 

Ga-ZSM-5 that is synthesized (167) in the presence of methylamine is characterized by a uniform distribution of gaUium throughout the framework. When both aluminum and gallium are present in the gel precursor, mixed complexes with methylamine are formed that are incorporated into the crystal lattice at different rates, while some unreacted gaUium amine 

Kofke et al. (168) determined the concentration of gaUium in the framework of MFI-type materials by adsorption methods. KUk et al. (76) investigated the gaUium incorporation by using high-field Ga MAS NMR spectroscopy, showing that gallium preferentiaUy occupies the framework positions in Ga-MFI materials that are prepared by direct synthesis from a gel. 

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Table 1.4 Synthesis of gallium-containing zeotype materials... 

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