For1ation of Zeolites: A Molecular Description

1987 ◽  
Vol 111 ◽  
Author(s):  
Prabir K. Dutta ◽  
M. Puri ◽  
D. C. Shieh
Keyword(s):  
Raman Spectroscopy ◽  
Vibrational Spectra ◽  
Crystallization Process ◽  
Building Blocks ◽  
Monovalent Cations ◽  
Zeolite X ◽  
Zeolite Formation ◽  
Amorphous Aluminosilicate ◽  
Molecular Description

AbstractRaman spectroscopy of the solution, solid and gel phases present during crystallization of zeolite X was investigated. The vibrational data indicate that an amorphous aluminosilicate solid, composed primarily of four membered aluminosilicate rings is in contact with monomeric silicate ions during the prenucleation stages of the zeolite formation. No intermediate building blocks specific to zeolite X could be discerned from the vibrational spectra. The influence of a series of monovalent cations on the crystallization process was also examined, and a model of zeolite formation has been proposed.

ADSORPTIVE AND GAS CHROMATOGRAPHIC PROPERTIES OF VARIOUS CATIONIC FORMS OF ZEOLITE X

1964 ◽  
Vol 42 (10) ◽  
pp. 2340-2350 ◽  
Author(s):  
H. W. Habgood
Keyword(s):  
Ionic Radius ◽  
Adsorption Process ◽  
Divalent Cations ◽  
Chromatographic Retention ◽  
Monovalent Cations ◽  
Zeolite X ◽  
Heats Of Adsorption ◽  
Quadrupole Interactions ◽  
Silver Compound ◽  
Retention Volumes

Gas chromatographic retention volumes for O2, N2, CH4, C2H6, C3H8, C4H10, C2H4, and C3H6 have been measured over a range of temperatures between 25 and 400 °C, on columns of the following ion-exchanged forms of zeolite X: Li+, Na+, K+, Mg++, Ca++, Ba++, and Ag+. In addition, for AgX zeolite, full isotherms have been determined for O2, N2, C2H6, and C2H4; and for NaX zeolite, isotherms for C2H6 and C2H4. The gas chromatographic retention volumes agree well with the isotherms in the case of NaX but are significantly low for AgX, presumably as the result of at least a portion of the adsorption process being slow. The heats of adsorption on NaX agree well with literature values for O2, N2, CH4, and C2H6 but are low for C3H8 and C4H10; further indication of slow processes and hence of a limitation of the g.c. technique. The observations can be correlated qualitatively in terms of the interplay of the following effects: (a) cationic field increases with decreasing ionic radius; (b) shielding of smaller cations is greater—at least in the six-membered oxygen-ring sites; (c) divalent cations, while having greater fields, are only half the number of monovalent cations and tend to be found in less exposed sites; and (d) the polarizing power of silver ion, which also occupies all types of exposed sites, is very strong. The most intense interactions were found with AgX; with ethylene a much stronger complex is formed than has been reported for any other silver compound. The significance of molecular quadrupole interactions on these heteroionic surfaces is shown by the much weaker cationic effects observed with O2 (which has negligible quadrupole moment) than with nitrogen.

Crystallization process of amorphous GaSb films studied by Raman spectroscopy

1995 ◽  
Vol 77 (8) ◽  
pp. 4044-4048 ◽  
Author(s):  
J. H. Dias da Silva ◽  
S. W. da Silva ◽  
J. C. Galzerani
Keyword(s):  
Raman Spectroscopy ◽  
Crystallization Process

Synthesis and vibrational spectra of complexes of small carboxylic acids with 18-crown-6

1985 ◽  
Vol 63 (7) ◽  
pp. 1457-1462 ◽  
Author(s):  
Rodrique Savoie ◽  
André Rodrigue ◽  
Marie Pigeon-Gosselin ◽  
Robert Chênevert
Keyword(s):  
Raman Spectroscopy ◽  
Carboxylic Acids ◽  
Vibrational Spectra ◽  
Acid Water ◽  
Neutral Component ◽  
Infrared And Raman Spectroscopy ◽  
O 18

The neutral-component complexes (HCOOH)3•(18-crown-6)2, (CH3COOH)2•18-crown-6, and various halogenated CH3COOH/18-crown-6 adducts have been isolated and studied by infrared and Raman spectroscopy. The halogenated (F, Cl, and Br) derivatives, which occur as (acid•water)x•18-crown-6(x = 1 or 2) adducts, probably have a structure which is similar to that of the known CH2(CN)COOH•H2O•18-crown-6 complex.

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