Theses and Dissertations at Montana State University (MSU)
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Item Stereoselective allylic cyclizations and rearrangements(Montana State University - Bozeman, College of Letters & Science, 2022) Stankevich, Ksenia Sergeyevna; Chairperson, Graduate Committee: Sharon NeufeldtHerein, we aim to explore the unique reactivity of allyl groups in two different areas: synthesis of densely functionalized five-membered ring systems and mechanistic studies of Pd- catalyzed formation of complex quaternary nitriles. The first part addresses the paucity of methods available for the formation of highly substituted five-membered rings, which are a common motif in natural compounds and pharmaceuticals. We developed a method that provides access to cyclopentenols and methylene cyclopentenols via the union of the Claisen rearrangement and Sakurai allylation. In this instance, the Claisen rearrangement allows for the stereospecific generation of the carbon framework, whereas the intramolecular Sakurai allylation provides a stereoselective cyclization reaction. For 1,2,5-trisubstituted cyclopenten-1-ols this approach has proven to be highly general and stereoselective, furnishing a library of cyclized products in good and very good yields and >20:1 diastereomeric ratio. For 1,2,5-trisubstituted 3- methylene cyclopentan-1-ols, we have developed a stereodivergent method whereby the one-pot stepwise Claisen-Sakurai reaction provided anti-, anti- product and the cascade Claisen-Sakurai reaction furnished syn-, anti- product as a major diastereomer with good yield. In both cases reaction mechanism was investigated to uncover the origin of diastereoselectivity using density functional theory. The second part of this research covers investigating the mechanism of a Pd- catalyzed double rearrangement to form quaternary nitriles, which are molecules of synthetic interest. We studied the mechanism of recently developed highly complex auto-tandem catalytic double allylic rearrangement of N-alloc-N-allyl ynamides to complex quaternary nitriles using density functional theory. This reaction proceeds through two separate and distinct catalytic cycles with both decarboxylative Pd-pi-allyl and Pd(0)-promoted aza-Claisen rearrangements occurring. We discovered previously unreported concomitant decarboxylation/C-C bond formation, reversible C-N ionization and a Pd(0) catalyzed [3,3]-rearrangement along with its stepwise variant. These catalytic cycles are characterized by the highly dynamic nature of the catalyst systems with large degrees of conformational flexibility and a flat potential energy surface. Our studies have rationalized the reactivity observed and can be further developed into predictive models for ligand and catalyst screening.Item Alkali-silica reactivity in the state of Montana(Montana State University - Bozeman, College of Engineering, 2020) Siegner, Ashton Amelia; Chairperson, Graduate Committee: Michael Berry and Kirsten Matteson (co-chair)While ASR has been documented as an issue in many states, little work has been conducted to determine the presence/potential of ASR in Montana. Thus, the primary objective of this research was to evaluate the potential for deleterious ASR in the state of Montana. In connection with this goal, a literature review was conducted to summarize the ASR practices used by neighboring state departments of transportation, as well as several federal agencies. Three potential cases of ASR damage in the state were identified and investigated using the Los Alamos Staining Method and ASTM C856. These sites included two at the Billings Logan International Airport and one at the Willow Creek Dam Spillway. Additionally, the reactivity eight aggregates, selected from various locations around the state, was tested in accordance with ASTM C1260 (Accelerated Mortar Bar Test), AASHTO T380 (Miniature Concrete Prism Tests). The literature review concluded that Canada and all other regional states explored, with the exception of North Dakota, directly addressed ASR in their material specifications, to varying degrees. The FHWA defers to individual states to determine ASR practices, while the FAA has fairly stringent specifications. The hardened concrete analyses conducted for the two Billings Logan International Airport Los sites indicated the presence of ASR in both locations; more specifically, the damage was classified as severe/Type V according to two separate criteria. The results of the Willow Creek Dam Spillway petrographic examination indicated the severity of the ASR distress observed in the spillway varied based on location, with advanced ASR detected in the ogee. This aspect demonstrated that cases of ASR in Montana do exist, and that the infrastructure in the state is susceptible to this type of failure mechanism. The results of the aggregate testing indicated that all the fine aggregates were reactive and very highly reactive according to ASTM C1260 and AASHTO T380, respectively. Two of the four coarse aggregates were innocuous according to ASTM C1260, while all of the coarse aggregates were reactive, to varying degrees, according to AASHTO T380. It was concluded that Montana's aggregates are susceptible to ASR.Item Microbially induced calcium carbonate precipitation: meso-scale optimization and micro-scale characterization(Montana State University - Bozeman, College of Engineering, 2020) Zambare, Neerja Milind; Chairperson, Graduate Committee: Robin Gerlach and Ellen G. Lauchnor (co-chair); Ellen Lauchnor and Robin Gerlach were co-authors of the article, 'Controlling the distribution of microbially precipitated calcium carbonate in radial flow environments' in the journal 'Environmental science and technology' which is contained within this dissertation.; Robin Gerlach and Ellen Lauchnor were co-authors of the article, 'Spatio-temporal dynamics of strontium partitioning with microbially induced calcium carbonate precipitation in porous media flow cells' submitted to the journal 'Environmental science & technology' which is contained within this dissertation.; Robin Gerlach and Ellen Lauchnor were co-authors of the article, 'Co-precipitation of strontium and barium' submitted to the journal 'Environmental science & technology' which is contained within this dissertation.; Nada Naser, Robin Gerlach and Connie Chang were co-authors of the article, 'Visualizing microbially induced mineral precipitation from single cells using drop-based microfluidics' submitted to the journal 'Nature methods' which is contained within this dissertation.Microorganisms have the potential to impact processes on a scale orders of magnitude larger than their size. For example, microbe-mineral interactions at the micro-scale can drive macro-scale processes such as rock formation and weathering. Many bioremediation technologies derive inspiration from microbial mineralization processes. Microbially induced calcium carbonate precipitation (MICP) can produce calcium carbonate (CaCO 3) precipitates which can be utilized as a biological cement to strengthen porous media by reducing fluid permeability in subsurface fractures or as an immobilization matrix to remove metal contaminants dissolved in groundwater. To make MICP a feasible and successful bioremediation technology in the world outside the lab, it is necessary to bridge the gap between the meso-scale research studies and macro-scale applications. This thesis focuses on such meso-scale studies but also contributes to bridging the gap in the other direction, i.e., meso-scale to micro-scale to gain a fundamental understanding of the cellular level processes behind MICP. The research presented here investigates two applications of MICP with a focus on controlling precipitate distribution and process efficiency in target environments. Subsurface precipitate distribution and metal partitioning during MICP were studied in novel reactive transport systems that mimic application-environment conditions. A radial flow reactor was used to study the spatial distribution of precipitates in conditions similar to subsurface injection well environments. The distribution and degree of metal partitioning during MICP was investigated in batch reactors and porous media flow cells to study kinetics and reactive transport effects on kinetics. In the radial flow environment, more precipitates formed away from the center injection zone. Results showed that longer reactant residence times and an equimolar ratio of calcium to urea were able to maximize precipitation efficiency. Metal partitioning could be maximized at low reactant flow rates and low metal concentrations. The novel flow cell set up used revealed a spatial decoupling between ureolysis and precipitation. A micro-scale investigation of the fundamental MICP process itself is presented wherein microbe-mineral interactions are observed at the cell level. A semi-correlative approach to investigating individual precipitates in microdroplets is presented, using a multitude of microscopy and microanalysis techniques. The presented studies capture MICP across a range of scales.Item An investigation of the reactions of supercritical CO 2 and brine with the Berea sandstone, muscovite, and iron bearing minerals(Montana State University - Bozeman, College of Letters & Science, 2015) Mangini, Seth Alexander; Chairperson, Graduate Committee: Mark L. SkidmoreThe reduction of anthropogenic CO 2 emissions while still generating energy is a challenge that society faces. Most current energy production comes from fossil fuels that increase atmospheric CO 2 concentrations. Pending a breakthrough in clean energy production, technological solutions that increase efficiency and sequester CO 2 are required. Carbon Capture and Storage (CCS) or carbon sequestration technology can provide part of the solution by providing disposal of point source CO 2 emissions. The research described in this thesis aims to aid development of CCS technology. There are three parts to the thesis. First, is an experimental study of the Berea sandstone to determine the reactivity of its minerals, as these could impact its potential as a reservoir for CO 2 storage. Cores of Berea were placed in a "flow-through reactor" that pumped a continuous stream of supercritical CO 2 (scCO 2) mixed with simulated groundwater through the rock. Chemical and physical changes to the solid, liquid and gas phases were monitored. Second, batch experiments were conducted to study the behavior of pyrite, magnetite, hematite, and muscovite when subjected to simulated groundwater and scCO 2. Third, is an outcrop study of the Devonian Jefferson Formation, a carbonate formation to serve as an analog to the same formation in the subsurface where it is the target of a Department of Energy CCS pilot project. The field study provided analysis of the mineralogy, sedimentology, and stratigraphy so as to better understand its potential as a reservoir for CO 2 storage. The flow-through experiments on the Berea sandstone demonstrated that carbonate cement and iron oxides were reactive phases. It was equivocal as to whether muscovite was reactive. The batch experiments quantified the reactivity of iron oxides and pyrite and demonstrated significant dissolution of the scCO 2, such that supercritical conditions were not maintained for the duration of the experiment. The batch experiments also showed that muscovite was not reactive within the time frame of the Berea flow-through experiments (72 hours), but was reactive over longer time periods (500+ hours). The field study indicated that the best potential reservoir zones of the Jefferson Formation are altered reef complexes composed mostly of dolomite.Item Molecular structure and reactivity of Vitamin B6/salicylaldehyde containing model enzymes(Montana State University - Bozeman, College of Letters & Science, 1984) Sykes, Andrew Gilchrist