Full metadata
Title
Mechanistic studies of hydrothermal organic geochemistry
Description
The hydrothermal chemistry of organic compounds influences many critical geological processes, including the formation of oil and gas reservoirs, the degradation and transport of organic matter in sedimentary basins, metabolic cycles in the deep subsurface biosphere, and possibly prebiotic organic synthesis related to the origin of life. In most previous studies of hydrothermal organic reactions the emphasis has been mainly on determining reaction product distributions, studies that provide detailed mechanistic information or direct evidence for specific reaction intermediates are rare. To develop a better understanding, I performed hydrothermal experiments with model ketone compound dibenzylketone (DBK), which serves as a quite useful tool to probe the bond breaking and forming processes in hydrothermal geochemical transformations. A careful study of reaction kinetics and products of DBK in Chapter 2 of this dissertation reveals reversible and irreversible reaction pathways, and provides evidence for competing ionic and radical reaction mechanisms. The majority of the observed products result from homolytic carbon-carbon and carbon-hydrogen bond cleavage and secondary coupling reactions of the benzyl and related radical intermediates.
In the third chapter of the dissertation, a novel hydrothermal photochemical method is studied, which enabled in situ independent generation of the relevant radicals and effectively separated the radical and ionic reactions that occur simultaneously in pure thermal reactions. In the following chapter, I focus on the role of minerals on ketone hydrothermal reactions. Minerals such as quartz and corundum have no detectable effect on DBK, whereas magnetite, hematite, and troilite all increase ketone reactivity to various extents. The influence of these iron-bearing minerals can be attributed to the mineral surface catalysis or the solution chemistry change that is presumably caused by dissolved inorganic species from minerals. In addition, some new discoveries on strong oxidizing effect of copper (II) ion under hydrothermal conditions are described in the latter chapter of the dissertation, where examples of clean and rapid reactions that converted alcohols to aldehyde and aldehydes to carboxylic acids are included.
In the third chapter of the dissertation, a novel hydrothermal photochemical method is studied, which enabled in situ independent generation of the relevant radicals and effectively separated the radical and ionic reactions that occur simultaneously in pure thermal reactions. In the following chapter, I focus on the role of minerals on ketone hydrothermal reactions. Minerals such as quartz and corundum have no detectable effect on DBK, whereas magnetite, hematite, and troilite all increase ketone reactivity to various extents. The influence of these iron-bearing minerals can be attributed to the mineral surface catalysis or the solution chemistry change that is presumably caused by dissolved inorganic species from minerals. In addition, some new discoveries on strong oxidizing effect of copper (II) ion under hydrothermal conditions are described in the latter chapter of the dissertation, where examples of clean and rapid reactions that converted alcohols to aldehyde and aldehydes to carboxylic acids are included.
Date Created
2014
Contributors
- Yang, Ziming (Author)
- Shock, Everett L (Thesis advisor)
- Gould, Ian R (Committee member)
- Wolf, George H. (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
xiv, 257 p. : ill. (some col.)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.25949
Statement of Responsibility
by Ziming Yang
Description Source
Retrieved on Dec. 17, 2014
Level of coding
full
Note
thesis
Partial requirement for: Ph.D., Arizona State University, 2014
bibliography
Includes bibliographical references
Field of study: Chemistry
System Created
- 2014-10-01 08:03:49
System Modified
- 2021-08-30 01:32:39
- 3 years 2 months ago
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