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Thermochemistry of Pure-Silica Zeolites

Piccione, Patrick M. and Laberty, Christel and Yang, Sanyuan and Camblor, Miguel A. and Navrotsky, Alexandra and Davis, Mark E. (2000) Thermochemistry of Pure-Silica Zeolites. Journal of Physical Chemistry B, 104 (43). pp. 10001-10011. ISSN 1520-6106. https://resolver.caltech.edu/CaltechAUTHORS:20170517-070821051

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Abstract

A series of pure-silica molecular sieves (structural codes AST, BEA, CFI, CHA, IFR, ISV, ITE, MEL, MFI, MWW, and STT) is investigated by high-temperature drop solution calorimetry using lead borate solvent at 974 K. The enthalpies of transition from quartz at 298 K (in kJ/mol) are AST, 10.9 ± 1.2; BEA, 9.3 ± 0.8; CFI, 8.8 ± 0.8; CHA, 11.4 ± 1.5; IFR, 10.0 ± 1.2; ISV, 14.4 ± 1.1; ITE, 10.1 ± 1.2; MEL, 8.2 ± 1.3; MFI, 6.8 ± 0.8; MWW, 10.4 ± 1.5; and STT, 9.2 ± 1.2. The range of energies observed is quite narrow at only 6.8−14.4 kJ/mol above that of quartz, and these data are consistent with and extend the earlier findings of Petrovic et al. The enthalpy variations are correlated with the following structural parameters:  framework density, nonbonded distance between Si atoms, and framework loop configurations. A strong linear correlation between enthalpy and framework density is observed, implying that it is the overall packing quality that determines the relative enthalpies of zeolite frameworks. The presence of internal silanol groups is shown to result in a slight (≤2.4 kJ/mol) destabilization of the calcined molecular sieves by comparing calorimetric data for MFI and BEA samples synthesized in hydroxide (containing internal silanol groups) and fluoride (low internal silanol group density) media.


Item Type:Article
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URLURL TypeDescription
http://dx.doi.org/10.1021/jp002148aDOIArticle
http://pubs.acs.org/doi/abs/10.1021/jp002148aPublisherArticle
ORCID:
AuthorORCID
Camblor, Miguel A.0000-0001-9591-3432
Navrotsky, Alexandra0000-0002-3260-0364
Davis, Mark E.0000-0001-8294-1477
Additional Information:© 2000 American Chemical Society. Received 13 June 2000. Published online 4 October 2000. Published in print 1 November 2000. Financial support for this work was provided by the Chevron Research and Technology Company. The calorimetric studies were supported by National Science Foundation Grant DMR 97-31782. P.M.P. thanks Katsuyuki Tsuji for providing one of the samples used in this study and Michael Gordon (Caltech) for helping in the design of sample transfer vessels. Comments by Dr. Stacey I. Zones (Chevron) are appreciated.
Funders:
Funding AgencyGrant Number
Chevron Research and Technology CompanyUNSPECIFIED
NSFDMR 97-31782
Issue or Number:43
Record Number:CaltechAUTHORS:20170517-070821051
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170517-070821051
Official Citation:Thermochemistry of Pure-Silica Zeolites Patrick M. Piccione, Christel Laberty, Sanyuan Yang, Miguel A. Camblor, Alexandra Navrotsky, and Mark E. Davis The Journal of Physical Chemistry B 2000 104 (43), 10001-10011 DOI: 10.1021/jp002148a
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77520
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:18 May 2017 18:51
Last Modified:09 Mar 2020 13:19

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