Despite comprehensive studies addressing the chemical kinetics of butanol isomers,
relevant uncertainties associated with the emissions of relevant pollutants
persists. Also, a lack of chemistry knowledge of processes designed to produce
biofuels limits their implementation at industrial scales. Therefore, the first objective
of this thesis was to use cutting-edge kinetic theories to calculate rate constants
of propen-2-ol, 1-pronenol, and vinyl alcohol keto-enol tautomerizations,
which account for the production of the harmful carbonyl species. The second
objective was to use the predictive capabilities of dynamic theories to reveal new
chemistry of syngas oxy-combustion in supercritical CO2 and complexities of the
zeolite dealumination, two processes involved in coal and biomass conversion.
Rate constants computations considered transition state theory with variational
effects, tunneling correction, and multistructural torsional anharmonicity. The
study also included pressure effects by using and improving the system-specific
quantum Rice-Ramsperger-Kassel/modified strong collision model. The atomistic
simulations used ReaxFF force fields in hydrogen/oxygen/carbon monoxide/
carbon dioxide mixtures to represent the syngas system and an MFI zeolite
with different water loading to model the dealumination. The results show
that the studied assisted tautomerizations have much lower energy barriers than
the unimolecular process. However, the “catalytic” effect is efficient only if the
partner molecule is at high concentrations. Pressure effects are pronounced in the chemically activated tautomerizations, and the improved algorithm to compute
pressure-dependent rate constants overcomes the initial difficulties associated
with its application to C3 or larger molecules at temperatures above 800-1000
K. Reactive molecular dynamics simulations revealed the role of CO2 as an initiator
in the syngas oxy-combustion and a new step involving the formation of
formic acid. Those simulations for the zeolite dealumination process also showed
that proton transfer, framework flexibility, and aluminum dislodging mediated
by silicon reactions are complex dynamic phenomena determining the process.
These aspects complement the dealumination theory uncovered so far and establish
new paths in the study of water-zeolite interactions. Overall, the rate
constants computed in this work reduce relevant uncertainties in the chemical
kinetic mechanisms of alcohol oxidation, and the molecular dynamics simulations
broaden the chemical knowledge of processes aimed at the utilization of alternative
energy resources.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/694304 |
| Date | 21 August 2023 |
| Creators | Grajales Gonzalez, Edwing |
| Contributors | Sarathy, Mani, Physical Science and Engineering (PSE) Division, Schwingenschlögl, Udo, Ruiz-Martinez, Javier, Corchado Martín-Romo, José Carlos |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Rights | 2024-09-10, At the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation will become available to the public after the expiration of the embargo on 2024-09-10. |
| Relation | N/A |
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