Physical Sciences and Mathematics Commons^™

Actinide Behavior In Soft Ligand Environments And Higher Oxidation States Of Neptunium In Aqueous Media With Solid-State Synthesis Of Np(Vii) Compounds, Kelly Floyd Seeley

UNLV Theses, Dissertations, Professional Papers, and Capstones

The fundamental properties of Uranium and Neptunium were investigated with Powder X-Ray Diffraction (PXRD) to study the behavior or 5f electrons with chalcogen, alkali metals, and alkaline earth metals. Two novel compounds were generated: NaCuUS₃ and NaCuNpS₃. There are several crystal structures that form in the family of AMM’Q (A = s-block, M = d-block, M’ = d-block or f-block, and Q = chalcogen), with oxidation states of A¹⁺, M¹⁺, M’⁴⁺, and Q^2- ions from the family of type I compounds. Work was continued to …

Mechanisms Of Formation Of Novel Guanine-Guanine Cross-Links As Major End Products During One-Electron Oxidation Of Guanine Derivatives, Evan Dunn

Undergraduate Honors Theses

Guanine (G), as the most oxidizable base in DNA, is the major focus of studies of oxidation damage to DNA. The present thesis reports the first detailed characterization of G dimerization products potentially resulting from recombination of neutral G• radicals. Previous research has discovered a novel type of products of G• dimerization, D1 and D2, formed from one-electron oxidation of G derivatives. However, the mechanism of this dimerization remains elusive. While there appears to be a tautomeric equilibrium between two forms of G•, G(N₁-H)• or G(N₂-H)•, it remains unclear which intermediate participates in the formation of …

Deposited Cigarette Smoke As A Driver Of Oxidation And Partitioning Processes On Indoor Surfaces, April Hurlock

Honors Theses

Despite the large amount of time that individuals spend indoors during their lives, very little attention was paid to the chemistry that occurs on indoor surfaces until recently. Although not visible to the naked eye, physical and chemical processes, such as partitioning and oxidation, are occurring on virtually every indoor surface in a typical household. Indoor pollutants, ranging from skin oils to environmental cigarette smoke, drive a lot of these processes. The transformation of indoor surfaces by indoor pollutants can increase chemical exposure risks as new irritants or carcinogens can be introduced to the surfaces. In this thesis, I describe …

Exploration Of Metal-Carbonyl Complexes For Decarbonylation Reactions, Rebekah C. Krupa

Graduate Theses, Dissertations, and Problem Reports

In recent years, transition metal-mediated decarbonylation reactions have emerged as an alternative to conventional cross-coupling methods due to the advantages associated with the use of carbonyl-containing functionalities as coupling electrophiles instead of organohalides found in traditional cross-coupling reactions. This, coupled with the ubiquity of carbonyl-containing compounds in pharmaceuticals and non-biodegradable chemicals, has led to the interest in developing efficient systems for transition metal-catalyzed decarbonylation. However, these reactions are commonly limited to stoichiometric amounts of metal reagents due to the strong metal-carbonyl bond formed during transition metal-mediated decarbonylation. With the goal of gaining a better mechanistic understanding of CO dissociation in …

Infiltration-Controlled Combustion Of Lithium And Magnesium Powders And Reactions Of Lithium With Oxygen And Carbon Dioxide, Kevin Samuel Estala Rodriguez

Open Access Theses & Dissertations

Chemical heat integrated power systems are of great interest for space missions where solar energy, nuclear energy, and batteries are not available or are not practical to use. A new concept of a power system is a metal combustor coupled with a chemical oxygen generator, where the generated oxygen infiltrates through the metal powder or combustion products. The combustion of lithium and magnesium powders under these conditions has not been studied yet. The present work investigates combustion of magnesium powder and stabilized lithium metal powder (SLMP) ignited by a laser inside a closed chamber filled with O2 or CO2. It …

Fast Photochemical Oxidation And Footprinting Of Proteins Via Trifluoromethyl Radical Chemistry, Elaine Morrow

Honors Theses

Fast photochemical oxidation of proteins (FPOP) is a useful tool in proteomics because of the ability for modifications to occur on the scale of microseconds which reduces the modifications to tertiary and quaternary structure allowing for more accurate labeling of the protein. Labels for FPOP are generated from various radicals in our experiments which include hydroxyl radicals and trifluoromethyl radicals. Hydroxyl radicals are easily generated by using an excimer laser (KrF laser, 248 nm) or a UV flash lamp (as a part of the Fox™ System) by the photolysis of hydrogen peroxide. Trifluoromethyl radicals, however, need hydroxyl radicals to be …

Effects Of Nitrate On Arsenic Mobilization During Aquifer Storage And Recovery, Hania Hawasli

USF Tampa Graduate Theses and Dissertations

Aquifer storage and recovery technology is used to sustain water resources and to prevent saltwater intrusion. The injected water can come from various resources, including treated wastewater. In pilot ASR studies in the Tampa Bay region, researchers found high As concentrations in the recovered water from the oxidation of the arsenopyrite that is embedded in the aquifers. The presence of dissolved O2 in the injected water is a major factor in the arsenopyrite oxidation during ASR, however the effects of NO3- on the arsenopyrite has not been studied yet. This is an important knowledge gap because injected water may contain …

Stability Of Group Four Monochalcogenides In Water And Air, William Shattuck

Graduate Theses and Dissertations

Previously published works have simulated the behavior of monolayer group IV monochalcogenides and predicted them to have very useful electronic properties. These simulations have also predicted that monolayers of group IV monochalcogenides will degrade quickly when exposed to water, even in extremely low concentrations. We hypothesize that thin samples of these materials will show signs of degradation if left in air and in water for an extended period of time.

Samples of each of the four monochalcogenides (GeS, GeSe, SnS and SnSe) were exfoliated onto clean oxidized silicon substrates. Chemical analysis showed the SnSe samples were contaminated, so they were …

Synthesis, Characterization, And Kinetics Studies Of New Cobalt Complexes For The Production Of H2 In Acidic Media, Michael John Celestine

Chemistry & Biochemistry Theses & Dissertations

The kinetics and mechanism of the oxidation of [Co(dmgBF₂)₂(OH₂)₂] (where dmgBF₂ = difluoroboryldimethylglyoximato) by sodium hypochlorite (NaOCl), sodium bromate (NaBrO₃), and bromine (Br₂₎ was investigated by stopped-flow spectrophotometry at 450 nm over a wide temperature range. The pK_a1 value for [Co(dmgBF₂)₂(OH₂)₂] was calculated as 5.27 ± 0.14 at I = 0.60 (NaCl). From the variation in pH studies, the activation parameters were derived from the proposed mechanisms for NaOCl, ΔH_1*, ΔH_2*, ΔS_1*, and …

Approaches Towards The Synthesis Of Ketamine Metabolites, Ann K. Patrick

Honors Theses

Major Depressive disorder (MDD) plagues society and stands at the forefront of research as MDD affects approximately 16% of the population. Pharmaceutical drugs, including the selective serotonin reuptake inhibitors (SSRIs), have been used for MDD treatment and remain a popular option today. However, current antidepressant treatments have proven to be ineffective in just less than half of the patients. Research continues with the goal to better understand the mechanisms of the pathology of depression and to search for other treatment options. For example, the stress-neurogenesis hypothesis investigates the role of stress and decreased neuroplasticity within MDD.

Supporting the stress-neurogenesis hypothesis, …

Ferrate(Vi) For Wastewater Treatment : Phosphorus Removal, Lei Zheng

Theses, Dissertations and Culminating Projects

Phosphorus (P) is a major nutrient present in municipal wastewater. Without proper treatment and management, residual P in treated wastewater finally enters into natural receiving water bodies. Nutrient pollution resulting from excessive P, together with the other nutrient, i.e. nitrogen (N), is a leading cause of eutrophication, a ubiquitous U.S. water quality issue. An overgrowth of algae during eutrophication brings extremely adverse impacts on the water quality. The algal bloom can rapidly deplete dissolved oxygen, lead to the death of aquatic life, increase water turbidity, and cause taste and odor issues. Moreover, some harmful algal boom can produce toxins to …

Carbon Oxidation At The Atomic Level: A Computational Study On Oxidative Graphene Etching And Pitting Of Graphitic Carbon Surfaces, Simon Schmitt

Theses and Dissertations--Mechanical Engineering

In order to understand the oxidation of solid carbon materials by oxygen-containing gases, carbon oxidation has to be studied on the atomic level where the surface reactions occur. Graphene and graphite are etched by oxygen to form characteristic pits that are scattered across the material surface, and pitting in turn leads to microstructural changes that determine the macroscopic oxidation behavior. While this is a well-documented phenomenon, it is heretofore poorly understood due to the notorious difficulty of experiments and a lack of comprehensive computational studies. The main objective of the present work is the development of a computational framework from …

Electrochemical Determination Of Surface Area-To-Volume Ratio For Metal Nanoparticle Analysis., Jay Narayan Sharma

Electronic Theses and Dissertations

This dissertation describes an electrochemical approach for measuring the surface area-to-volume ratio (SA/V) of electrode-attached metal nanoparticles (NPs), which was used to analyze their size, aggregation state, and porosity. This dissertation further describes the effect of the metal NP electrode assembly method on the SA/V, which is related to metal NP catalytic activity and stability. Cyclic voltammetry (CV) in acid electrolyte followed by anodic stripping voltammetry (ASV) in KBr electrolyte allows the electrochemical measurement of the SA/V of electrode-attached Au nanospheres (NSs). In CV, the forward scan produces a thin surface Au₂O₃ layer on the Au NSs. …

Oxidative Depolymerization Of Lignin To Low Molecular Weight Aromatics, Yang Song

Theses and Dissertations--Chemistry

To date, most lignocellulosic biorefinery strategies have focused on optimizing conversion of cellulose to ethanol, leaving lignin as an underutilized biomass constituent. Lignin is engineered by nature with the intent to protect plants from chemical and biological attack; this leaves lignin with high structural irregularity and recalcitrance, rendering conversion of the lignin macromolecule to valuable products particularly challenging. Nevertheless, given that the economics of cellulosic ethanol production are strongly dependent on the value that can be obtained for the lignin co-product, the successful valorization of lignin is a crucial step in the transition towards a bio-based economy.

This thesis focuses …

The Investigation Of The Chlorine Initiated Oxidation Of 2-Phenylethanol And Stability Of Superalkali Lithium Substituted Silyls., Adam Otten

Master's Theses

This thesis investigates the combustion potential of 2-phenylethanol and the superalkali properties of small lithium substituted silicon compounds. All combustion experiments were performed at the Advanced Light Source of Lawrence Berkeley National Laboratory at the Chemical Dynamics Beamline 9.0.2. The chlorine initiated oxidation of 2PE was investigated at 298 and 550 K using a multiplex photoionization mass spectrometer, coupled with the tunable vacuum ultraviolet radiation. Reaction products were identified using kinetic time traces and photoionization spectra.

Additionally, the stability of small superalkali silicon-lithium compounds has also been investigated. All structures and energetics were calculated using the CBS-QB3 composite method.

The …

Determination Of The Oxidative Capacity Of Soot Toward Gsh And Characterization Of Soot Physicochemical Properties, Kaylee Troth

All Master's Theses

Fine atmospheric particulate matter (PM_2.5) emitted during the combustion of fossil and biomass fuels is known to adversely affect human health. While the underlying mechanisms are thought to be driven by the generation of reactive oxygen species (ROS), specific particle characteristics responsible for this detrimental effect are not well understood. In this research, the quantitative determination of the biologically relevant antioxidant, glutathione (GSH), was optimized for use as an indicator of oxidative stress to shed light on relevant particle characteristics. This was accomplished via fluorescent spectroscopy for GSH determination by way of reaction with o-phthalaldehyde (OPA), a …

Analysis Of Oxidation Of Carbon Monoxide On Rh (110), Razan Tanbour

Senior Honors Theses and Projects

81% of all rhodium (Rh) is used in automobile catalytic converters. Consequently, researchers have dedicated a lot of effort into understanding the behavior of nonmetal oxides on a Rh surface. Using a computer simulation program, we have studied the absorption and oxidation of carbon monoxide (CO) on a terraced Rh surface (lattice) with a width of three and a height of 10000 using a mechanism that describes the behavior at low temperatures. Varying the reaction activation energies (rate constants), and the mobility of the CO, led to changes in the surface coverages of oxygen and CO. Specifically, increasing the activation …

Oxidation Of Dibenzothiophene To Dibenzothiophene-Sufone Using A Molybdenum (Vi) Oxide Catalyst: A Kinetic Study Testing Solvent Dependency And Mole Ratio Efficiency, Tomas Trevino Jr.

Theses and Dissertations

Oxidative desulfurization (ODS) is currently a solution to hydrodesulphurization. Currently, industrial usage of hydrodesulphurization (HDS) is the common source for petroleum purification. Unfortunately, HDS comes with environmental and economical ramifications. Due to the problems and potential hazards being presented with HDS, ODS has become a topic of interest in research development. A kinetic study using molybdenum (VI) oxide as a catalyst was used in oxidative desulfurization. Factors such as mole ratio and solvent dependency were tested for efficiency. As activation energy was calculated to show maximum efficiency with respect to temperature and concentration. Gas Chromatography, FT-IR, and Mass Spectroscopy were …

The Oxidation State Of Hawaiian Magmas, Michael Vollinger

Masters Theses

In order to estimate the oxygen fugacity of Hawaiian lavas I have measured the ferric/ferrous ratios of samples from the 1984 eruption of Mauna Loa volcano and from the ongoing (1983-2017) Puu Oo eruption of Kilauea volcano. Fifteen samples were studied from the 21 day Mauna Loa eruption and 86 samples, erupted between 1983 and 2004, of the 34 year long Kilauea eruption. Both studies show that, in order to obtain reliable estimates of oxygen fugacity when, where, and how basaltic lava is sampled is of critical importance. Water-quenched lavas and spatter sampled at, or near vents, are less oxidized …

A Chlorine-Free Protocol For Processing Silicon, Germanium, And Tin, Michael J. Krause

Electronic Thesis and Dissertation Repository

Replacing molecular chlorine and hydrochloric acid with less energy- and risk-intensive reagents would dramatically improve the environmental impact of metal manufacturing at a time when demand for metals is rapidly increasing. Germanium and tin are classified as “critical” elements based on growing demand for these elements in technological applications, lack of suitable substitutes, and, for germanium, high dispersion in the environment making extraction of the element process-intensive. This thesis describes a recyclable quinone / catechol redox platform that provides an innovative replacement for elemental chlorine and hydrochloric acid in the conversion of germanium metal or tin metal to element tetrachloride …

The Investigation And Characterization Of The Reaction Of 2-Methylfuran And 2-Methyl-3-Buten-2-Ol With O(3p) And The Photodissociation Of Xylyl Bromide Isomers, Yasmin Fathi

Master's Theses

This thesis has studied the oxidation behavior of different biofuels or additives, 2-methyl-3-buten-2-ol and 2-methylfuran, in combustion experiments at the Chemical Dynamics Beamline held at the Advanced Light Source of the Lawrence Berkley National Laboratory. The oxidation of these fuels were initiated through O(³P) and the combustion experiments were analyzed using a multiplexed chemical kinetics photoionization mass spectrometer with tunable synchrotron radiation. Products of the different reactions were identified using kinetic profiles and further characterized using the photoionization spectra. The amount of each species was calculated using branching fractions.

Additionally, the unimolecular dissociation of the xylyl bromide isomers …

Homogeneous Ligand-Centered Hydrogen Evolution And Hydrogen Oxidation : Exploiting Redox Non-Innocence To Drive Catalysis., Andrew Z. Haddad

Electronic Theses and Dissertations

Hydrogen is a promising carbon-free fuel / energy carrier and is an essential building block for many industrial and agricultural processes. Rising energy demands have ignited interest in the development of carbon-free and carbon neutral energy sources. In this context, hydrogen is an attractive candidate—being energy-dense, carbon-free—and easily accessible through a two-electron reduction of water. Accordingly, many electrochemical homogeneous catalyst systems have been studied, with a focus on understanding the mechanism of hydrogen evolution proceeding through metal-hydride intermediates. However, there has been a renaissance in hydrogen evolution reaction (HER) catalyst design, with many groups implicating ligand redox non-innocence as a …

The Decline And Recovery Of Thermal Oxidative Stability Of Ultra-Low Sulfur Diesel Blends, Abigail Schoor Cohen

Electronic Theses and Dissertations

Dissertation supervised by Professor Bruce D. Beaver

The oxidative stability of ultra-low sulfur diesel (ULSD) has generally been expected to continuously decline over time. However, recent studies have suggested that it may fluctuate.^1-2 In this study, the oxidative stability of stored commercially purchased ULSD was monitored with a methanol extraction method.³ In this methodology, proposed by Hardy and Wechter, fuel blends are extracted with methanol before and after thermal stressing.⁴ The methanol-soluble layer contains the oxygenated and oxidizable components of the fuel (SMORS) and the change in this mass upon stressing thus represents the oxidative stability of …

The Use Of Sodium Persulfate In Hydraulic Fracturing Fluids: A Degradation Study Based On Furfural, Katherine Elizabeth Manz

Masters Theses

Hydraulic fracturing has allowed natural gas to become a viable energy source via extraction of unconventional shale reserves, but this process requires an enormous amount of water. To ensure a productive fracture, a proprietary blend of chemical additives is added to the water. In this research, a hydraulic fracturing chemical additive – an enzyme breaking agent – is analyzed for organic components using gas chromatography mass spectrometry. The chemical changes that occur over the course of a fracture are also investigated using one model chemical found in the additive, furfural, in order to help assess the environmental risk that hydraulic …

Biomimetic Tools In Oxidative Metabolism: Characterization Of Reactive Metabolites From Antithyroid Drugs, Kudzanai Chipiso

Dissertations and Theses

Toxicities of sulfur-based drugs have been attributed to formation of highly reactive sulfur oxo-acids and depletion of glutathione by the formation of reactive metabolites. Metabolic activation of these sulfur centers to conceivably toxic reactive metabolites (RMs) that can covalently modify proteins is considered the initial step in drug-induced toxicity. Despite considerable effort and research, detection and characterization of these RMs during drug development and therapy remains a challenge. Methimazole (MMI) and 6-propyl-2-thiouracil (PTU) are two commonly used antithyroid, sulfur-based drugs. Though effective, these drugs are associated with idiosyncratic toxicity. PTU has acquired a black box warning and physicians are calling …

Development Of Palladium Catalyzed Alkene Difunctionalization On Vinyl-Quinoline Type Substrate And Isolation Of Pd-Alkyl Intermediate, Lusha Xu

Electronic Theses and Dissertations

The synthesis of quinoline derivatives is a continuing issue facing organic chemists in both academia and industry. To address this problem, palladium-catalyzed alkene difunctionalization was developed to be a powerful and straightforward strategy of synthetic transformations for adding diversity to organic molecules. In this thesis, Pd-catalyzed olefin difunctionalization reactions of vinyl-quinoline type substrate via generating Pd-alkyl intermediates were mainly described. The reactions described herein are pursuing three significant goals: 1) to isolate and recrystallize Pd-alkyl complexes; 2) to achieve oxidation reactions on Pd-alkyl intermediate; and 3) to investigate stereochemistry of nucleopalladation step on vinyl-quinoline starting materials.

Establishing Chemical Mechanisms And Estimating Phase State Of Secondary Organic Aerosol From Atmospherically Relevant Organic Precursors, Shashank Jain

Graduate College Dissertations and Theses

Organic aerosol (OA) is a ubiquitous component of atmospheric particulate that influences both human health and global climate. A large fraction of OA is secondary in nature (SOA), being produced by oxidation of volatile organic compounds (VOCs) emitted by biogenic and anthropogenic sources. Despite the integral role of SOA in atmospheric processes, there remains a limited scientific understanding of the chemical and physical changes induced in SOA as it ages in the atmosphere. This thesis describes work done to increase the knowledge of processes and properties of atmospherically relevant SOA.

In the work presented in this thesis, I have worked …

Investigating The Influence Of Gold Nanoparticles On The Photocatalytic And Catalytic Reactivity Of Porous Tungsten Oxide Microparticles, Daniel P. Depuccio

Graduate College Dissertations and Theses

Tungsten oxide (WO3) is a semiconducting transition metal oxide with interesting electronic, structural, and chemical properties that have been exploited in applications including catalysis, gas sensing, electrochromic displays, and solar energy conversion. Nanocrystalline WO3 can absorb visible light to catalyze heterogeneous photooxidation reactions. Also, the acidity of the WO3 surface makes this oxide a good thermal catalyst in the dehydration of alcohols to various industrially relevant chemicals. This dissertation explores the photocatalytic and thermal catalytic reactivity of nanocrystalline porous WO3 microparticles. Furthermore, investigations into the changes in WO3 reactivity are carried out after modifying the porous WO3 particles with gold …

Towards Catalytic Oxidative Depolymerization Of Lignin, Justin K. Mobley

Theses and Dissertations--Chemistry

Lignin is one of the most abundant and underutilized biopolymers on earth. Primarily composed on three monolignol units (sinapyl, coniferyl, and p-coumaryl alcohol), lignin is formed through a radical pathway resulting in an assortment of linkages, of which the β-O-4 linkage is the most prevalent (up to 60% in some hardwood species). In planta, lignin plays an important role in water transport and in protecting plants from chemical and biological attack. Traditional attempts to depolymerize lignin have focused on the cleavage of β-O-4 linkages via thermal or reductive routes. However these pathways lead to low-value, unstable product mixtures. Moreover, …

The Investigation Of The Low Temperature Combustion Of Mesitylene And Tert-Amyl Methyl Ether By Synchrotron Photoionization Mass Spectrometry, Martin Yu-Hin Ng

Master's Theses

This thesis describes the combustion experiments performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) located at the Lawrence Berkeley National Laboratories (LBNL). The need for renewable fuel sources, the need for the study of their combustion in the contexts of homogenous charge combustion ignition (HCCI) engines can be found in Chapter 1. The components of the experimental set-up used throughout this thesis—time-of-flight mass spectrometer, Excimer laser, vacuum pumps and other components—and the components of ALS responsible in synchrotron radiation generation and processing—the linear accelerator, the booster ring, insertion devices, gas filters and monochromator are explained in …