Synthesis and characterization of gallosilicate MFI-type zeolites: effect of the gel composition on the crystallization rate

Gallosilicate MFI-type zeolites ([Ga]-ZSM-5) were synthesized at 170°C, with autogeneous pressure and agitation. Samples were characterized by 71Ga MAS n.m.r., XRD, i.r., X.p.s., and chemical analysis. The influence of synthesis parameters such as theSiO 2/Ga 2O 3,(TPA) 2O/SiO 2, andNa 2O/SiO 2 gel...

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Bibliographic Details
Published in:Zeolites 1994-09, Vol.14 (7), p.549-552
Main Authors: Giannetto, G., Papa, J., Perez, J., Garcia, L., Monque, R., Gabelica, Z.
Format: Article
Language:English
Subjects:
crystallization rate
gallosilicate
MFl-type zeolite
synthesis gel composition
Zeolite
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Summary:Gallosilicate MFI-type zeolites ([Ga]-ZSM-5) were synthesized at 170°C, with autogeneous pressure and agitation. Samples were characterized by 71Ga MAS n.m.r., XRD, i.r., X.p.s., and chemical analysis. The influence of synthesis parameters such as theSiO 2/Ga 2O 3,(TPA) 2O/SiO 2, andNa 2O/SiO 2 gel molar ratios on the crystallization kinetics were evaluated. Pure and highly crystalline [Ga]-ZSM-5 are formed after 20–24 h heating, independently of the gel composition, provided that traces of the template agent (tetrapropylammonium ions, TPA +) are present. Such particular behavior is related to the presence of very stable monomer gallate ions in the alkaline synthesis media that are readily incorporated in the MFI framework structure, irrespective of low oligomeric hydroxy-Al species present in similar conditions.
ISSN:0144-2449
1873-3115
DOI:10.1016/0144-2449(94)90189-9