Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-26T17:18:28.082Z Has data issue: false hasContentIssue false
  • English
  • Français

DFT Investigation of the Mechanism and Chemical Kinetics for the Gelation of Colloidal Silica

Published online by Cambridge University Press:  21 May 2013

Steven S. Burnett  and
James W. Mitchell
Steven S. Burnett
Affiliation:
Howard University 2300 Sixth Street, Rm. 1124, NW, Washington, DC 20059 U.S.A.
James W. Mitchell
Affiliation:
Howard University 2300 Sixth Street, Rm. 1124, NW, Washington, DC 20059 U.S.A.
Get access

Abstract

The mechanism for the gelation reaction of colloidal silica, Si(OH)4 +Si(OH)3 (O)- ----> Si2O8H5- + H2O, by an anionic pathway was investigated using density functional theory(DFT). Using transition state theory, the rate constants were obtained by analyzing the potential energy surface at the reactants, saddle point, and the products. In addition, reaction rate constants were investigated in the presence of ammonium chloride (NH4Cl) and sodium chloride (NaCl). These salts act as catalysts to induce gelation by destabilizing the double layer of colloidal silica to allow for Van der Waal interactions. Furthermore, it was observed that ammonium chloride plays an important role by initiating a hydride transfer allowing the reaction to proceed from the second transition state to the final product.

Keywords

chemical reactioncolloidsol-gel
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1547: Symposium M – Solution Synthesis of Inorganic Functional Materials—Films, Nanoparticles and Nanocomposites , 2013 , pp. 173 - 182
Copyright
Copyright © Materials Research Society 2013 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Bhandarkar, S. Sol-Gel Processing for Optical Communication Technology. J. Am. Ceram. Soc 87, 1180–1199 (2004).CrossRefGoogle Scholar
Hench, L. L. & West, J. K. The Sol-Gel Process. Chem. Rev. 1990, 33 – 72 (1961).Google Scholar
Johann Cho, M. S. P. S., Boccaccini, Aldo R.. Ceramic Matrix Composites Containing Carbon Nanotubes. J Mater Sci 44, 19341951 (2009).Google Scholar
Mora-Fonz, M. J., Catlow, C. R. A. & Lewis, D. W. Oligomerization and Cyclization Processes in the Nucleation of Microporous Silicas. Angew. Chem. Int. Ed. 44, 3082 – 3086 (2005).CrossRefGoogle ScholarPubMed
Pereira, J. C. G., C. R. A. C. & Price, G. D. Ab Initio Studies of Silica Based Clusters. Part II. Structures and Energies of Complex Clusters. J. Phys. Chem. A 103, 3268–3284 (1999).CrossRefGoogle Scholar
Nangia, S. & Garrison, B. J. Reaction Rates and Dissolution Mechanisms of Quartz as a Function of pH. Environ. Pollut. 112, 2027 – 2033 (2008).Google ScholarPubMed
Thuat, T. Trinh, A. P. J. J. & van Santen, R. A. Mechanism of Oligomerization Reactions of Silica. J. Phys. Chem. B 110, 23099–23106 (2006).Google Scholar
Stanic, V., T. H. E., Pierre, A. C. & Mikula, R. J. Chemical Kinetics Study of the Sol-Gel Processing of GeS2. J. Phys. Chem. A 105, 6136–6143 (2001).CrossRefGoogle Scholar
Brunet, F., M. D., Cabane, B. & Perly, B. Sol-Gel Polymerization Studied Through 29Si NMR with Polarization Transfer. J. Phys. Chem. 95, 944–951 (1991).CrossRefGoogle Scholar
Trinh, T. T., Jansen, A. P. J., van Santen, R. A., VandeVondele, J. & Meijer, E. J. Effect of Counter Ions on the Silica Oligomerization Reaction. Chem. Phys. 10, 1775 – 1782 (2009).Google ScholarPubMed
Mora-Fonz, M. J., Catlow, C. R. A. & Lewis, D. W. Modeling Aqueous Silica Chemistry in Alkali Media. J. Phys. Chem. C 111, 18155 – 18158 (2007).CrossRefGoogle Scholar
Trinh, T. T., Jansen, A. P. J. & van Santen, R. A. Mechanism of Oligomerization Reactions of Silica. J. Phys. Chem. B 110, 23099 – 23106 (2006).CrossRefGoogle ScholarPubMed
Pereira, J. C. G., Catlow, C. R. A. & Priceb, G. D. Silica Condensation Reaction: An Ab Initio Study. Chem. Commun. 6, 2 – 4 (2012). URL http://pubs.rsc.org.Google Scholar
Pereira, J. C. G., Catlow, C. R. A. & Price, G. D. Ab Initio Studies of Silica-Based Clusters. Part II. Structures and Energies of Complex Clusters. Microporous Mater. 103, 3268 – 3284 (1999).Google Scholar
Thuat, T. T. A Computational Study of Silicate Oligomerization Reactions. Ph.D. Thesis, Eindhoven University of Technology (2009).Google Scholar
Becke, A. D. Density-Functional Thermochemistry. III. The Role of Exact Exchange. J. Chem. Phys (1993).CrossRefGoogle Scholar
Stephens, P. J., , C. F. C., Devlin, F. J. & Frisch, M. J. Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra using Density Functional Force Fields. J. Chem. Phys (1998).Google Scholar
Tossell, J. A. Theoretical Study on the Dimerization of Si(OH)4 in Aqueous Solution and its Dependence on Temperature and Dielectric Constant. Geochim. Cosmochim. Acta 69, 283 – 291 (1981).CrossRefGoogle Scholar
Nangia, S. & Garrison, B. J. Reaction Rates and Dissolution Mechanisms of Quartz as a Function of pH. J. Phys. Chem. A 112, 2027–2033 (2008).CrossRefGoogle ScholarPubMed
Schmidt, M.W., J. S. M. J. S. N. K. S. T. M. J., Baldridge, K.K.. General Atomic and Molecular Electronic Structure System. J. Comput. Chem 14, 1347–1363 (1993).CrossRefGoogle Scholar
Bode, Brett M., Macmolplt, M. S. G.: A Graphical User Interface for Gamess. Journal of Molecular Graphics and Modeling 16, 133–138 (1998).CrossRefGoogle ScholarPubMed