Dissertation
SOLVENT EFFECTS ON THE ENERGETICS OF COMPLEXATION REACTIONS IN BINARY AQUEOUS METHANOL SOLUTIONS
Doctor of Philosophy (PhD), Washington State University
01/2014
Handle:
https://hdl.handle.net/2376/111131
Abstract
The separation of the lanthanides and actinides has been a focus of study for many years, most commonly for the purposes of purifying an element, nuclear reprocessing, or trace-level quantification. In some cases, simple carboxylic ligands are used in chromatographic separations schemes as complexing agents in the overall separation process, which can also include co-solvents, such as methanol. Predicting the influence of solvent composition on the complexation chemistry requires a foundation of knowledge that describes the thermodynamics in mixed solvent systems.
The studies described in this dissertation focus on the effect of methanol on aqueous background electrolytes and trivalent lanthanide complexes with the alpha-hydroxy carboxylate ligand, 2-hydroxy-2-methylbutyrate (HMBA). Computational techniques are applied to understand the effects of methanol on the solvation of sodium ions, chloride ions, and their interactions as ion pairs. The sodium and chloride ions were found to be solvate preferentially by water up to the highest methanol fraction studied (e.g., 50%). Potentiometry, calorimetry, and absorption spectroscopy were used to measure enthalpies (ΔH), entropies (ΔS), and free energies (ΔG) of lanthanide HMBA complexation in various aqueous methanol solvents. As the mole fraction of methanol increases, complexation becomes more exothermic with larger free energies; little change was observed with entropy. The results of these studies will aid in the design of separation processes involving the lanthanide elements in water-methanol binary solvents.
Additional studies focused on the development of an alternative detection method for microfluidic devices. A detection scheme for fissionable actinides would be beneficial for rapid identification of fissionable isotopes. The coupling of fission track analysis (FTA) with microfluidic chromatographic devices was investigated and a protocol for detection is described.
Metrics
28 File views/ downloads
19 Record Views
Details
- Title
- SOLVENT EFFECTS ON THE ENERGETICS OF COMPLEXATION REACTIONS IN BINARY AQUEOUS METHANOL SOLUTIONS
- Creators
- Amber Sue Donley
- Contributors
- Sue B Clark (Advisor)Kenneth L Nash (Committee Member)Nathalie A Wall (Committee Member)Linfeng Rao (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemistry, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 172
- Identifiers
- 99900581736501842
- Language
- English
- Resource Type
- Dissertation