skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Kinetics of Dissociations of Aluminum - Oxygen Bonds in Aqueous Complexes - An NMR Study

Abstract

OAK B262 The Kinetics of Dissociations of Aluminum--Oxygen Bonds in Aqueous Complexes--An NMR Study. In this project we determined rates and mechanisms of Al(III)-O bond rupture at mineral surfaces and in dissolved aluminum complexes. We then compared the experimental results to simulations in an attempt to predict rate coefficients. Most of the low-temperature reactions that are geochemically important involve a bonded atom or molecule that is replaced with another. We probe these reactions at the most fundamental level in order to establish a model to predict rates for the wide range of reactions that cannot be experimentally studied. The chemistry of small aluminum cluster (Figure) provides a window into the hydrolytic processes that control rates of mineral formation and the transformation of adsorbates into extended structures. The molecule shown below as an example exposes several types of oxygens to the bulk solution including seven structurally distinct sets of bridging hydroxyls. This molecule is a rich model for the aqueous interface of aluminum (hydr)oxide minerals, since it approaches colloidal dimensions in size, yet is a dissolved complex with +18 charge. We have conducted both {sup 17}O- {sup 27}Al- and {sup 19}F-NMR experiments to identify the reactive sites and to determine themore » rates of isotopic exchange between these sites and the bulk solution. The research was enormously successful and led to a series of papers that are being used as touchstones for assessing the accuracy of computer models of bond ruptures in water.« less

Authors:
Publication Date:
Research Org.:
University of California Davis (US)
Sponsoring Org.:
(US)
OSTI Identifier:
814687
DOE Contract Number:  
FG03-96ER14629
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 3 Sep 2003
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 58 GEOSCIENCES; ALUMINIUM OXIDES; CHEMICAL REACTION KINETICS; AQUEOUS SOLUTIONS; NUCLEAR MAGNETIC RESONANCE; DISSOCIATION; CHEMICAL BONDS; ALUMINIUM COMPLEXES; GEOCHEMISTRY

Citation Formats

Casey, William. The Kinetics of Dissociations of Aluminum - Oxygen Bonds in Aqueous Complexes - An NMR Study. United States: N. p., 2003. Web. doi:10.2172/814687.
Casey, William. The Kinetics of Dissociations of Aluminum - Oxygen Bonds in Aqueous Complexes - An NMR Study. United States. https://doi.org/10.2172/814687
Casey, William. Wed . "The Kinetics of Dissociations of Aluminum - Oxygen Bonds in Aqueous Complexes - An NMR Study". United States. https://doi.org/10.2172/814687. https://www.osti.gov/servlets/purl/814687.
@article{osti_814687,
title = {The Kinetics of Dissociations of Aluminum - Oxygen Bonds in Aqueous Complexes - An NMR Study},
author = {Casey, William},
abstractNote = {OAK B262 The Kinetics of Dissociations of Aluminum--Oxygen Bonds in Aqueous Complexes--An NMR Study. In this project we determined rates and mechanisms of Al(III)-O bond rupture at mineral surfaces and in dissolved aluminum complexes. We then compared the experimental results to simulations in an attempt to predict rate coefficients. Most of the low-temperature reactions that are geochemically important involve a bonded atom or molecule that is replaced with another. We probe these reactions at the most fundamental level in order to establish a model to predict rates for the wide range of reactions that cannot be experimentally studied. The chemistry of small aluminum cluster (Figure) provides a window into the hydrolytic processes that control rates of mineral formation and the transformation of adsorbates into extended structures. The molecule shown below as an example exposes several types of oxygens to the bulk solution including seven structurally distinct sets of bridging hydroxyls. This molecule is a rich model for the aqueous interface of aluminum (hydr)oxide minerals, since it approaches colloidal dimensions in size, yet is a dissolved complex with +18 charge. We have conducted both {sup 17}O- {sup 27}Al- and {sup 19}F-NMR experiments to identify the reactive sites and to determine the rates of isotopic exchange between these sites and the bulk solution. The research was enormously successful and led to a series of papers that are being used as touchstones for assessing the accuracy of computer models of bond ruptures in water.},
doi = {10.2172/814687},
url = {https://www.osti.gov/biblio/814687}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2003},
month = {9}
}