UZH-Logo

Effect of Counter Ions on the Silica Oligomerization Reaction


Trinh, T T; Jansen, A P J; van Santen, R A; VandeVondele, J; Meijer, E J (2009). Effect of Counter Ions on the Silica Oligomerization Reaction. ChemPhysChem, 10(11):1775-1782.

Abstract

The silicate oligomerization reaction is key to sol-gel chemistry and zeolite synthesis. Numerous experimental and theoretical studies have addressed the physical chemistry of silicate oligomers in the prenucleation stage of siliceous zeolite formation. Here we report a study of a silica condensation reaction in aqueous solution in the presence of counter ions (Li+ and NH4+). Ab-initio molecular dynamics simulations have been used to construct reaction energy diagrams including transition state free energies. Contact with Li+ as well as NH4+ increases the activat ion energies of the dimerization step compared to the situation in the absence of counterions. The presence of NH4+ has no effect on consecutive oligomerization steps. Hence NH4+ will increase the relative formation rate of larger oligomers.

The silicate oligomerization reaction is key to sol-gel chemistry and zeolite synthesis. Numerous experimental and theoretical studies have addressed the physical chemistry of silicate oligomers in the prenucleation stage of siliceous zeolite formation. Here we report a study of a silica condensation reaction in aqueous solution in the presence of counter ions (Li+ and NH4+). Ab-initio molecular dynamics simulations have been used to construct reaction energy diagrams including transition state free energies. Contact with Li+ as well as NH4+ increases the activat ion energies of the dimerization step compared to the situation in the absence of counterions. The presence of NH4+ has no effect on consecutive oligomerization steps. Hence NH4+ will increase the relative formation rate of larger oligomers.

Citations

19 citations in Web of Science®
20 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

0 downloads since deposited on 16 Dec 2009
0 downloads since 12 months

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Date:9 June 2009
Deposited On:16 Dec 2009 14:14
Last Modified:05 Apr 2016 13:34
Publisher:Wiley-Blackwell
ISSN:1439-4235
Additional Information:Free access at DOI
Publisher DOI:10.1002/cphc.200900006
Permanent URL: http://doi.org/10.5167/uzh-24476

Download

[img]
Filetype: PDF - Registered users only
Size: 1MB
View at publisher

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations