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Adsorption Of Propane On The Magnesium Oxide (100) Surface And Synthesis Of Anodized Aluminum Oxide, Michael John Felty

Doctoral Dissertations

This work is divided into two parts: the adsorption of propane on the magnesium oxide (100) surface and the synthesis of anodized aluminum oxide. The adsorption properties of propane on the MgO (100) surface were investigated using high-resolution volumetric isotherm techniques and a computational study was accomplished using Materials Studio. From the adsorption work, the two-dimensional isothermal compressibility, the isosteric heat of adsorption, the differential enthalpy, and the differential entropy of adsorption can be calculated. Three distinct layers of propane were observed to form on the MgO (100) surface and it was determined that a phase transition occurs at 162 …

Molecular Hydrogen Adsorbed On Mgo (100) Surfaces: A Thermodynamic Study, Lillian Ruth Frazier

Doctoral Dissertations

The thermodynamics of molecular hydrogen adsorbed on MgO (100) surfaces has been examined using high resolution volumetric adsorption isotherm techniques. These studies were undertaken using highly perfect, narrow size distributed MgO nanocubes with essentially single (100) facet exposure and extremely high chemical purity. A narrowly spaced (in temperature) series of isotherms were performed between the temperatures of ~7K and the triple point (13.8 K) using H₂ and D₂ gas.

A minimum of five, and in some cases seven, discrete adsorption steps are clearly observed in each isotherm trace. Analysis of these data indicate that the monolayer film forms …

New Carbon-Carbon Bond Forming Reactions Mediated By Boron And Transition Metal Halides, Travis R. Quick

Doctoral Dissertations

This dissertation summarizes the recent use of boron and transition metal halides to form new carbon-carbon bonds. Several novel reactions have been discovered. These include the haloallylation of aryl aldehydes with boron trihalide; alkyne-aldehyde couplings mediated by boron trihalide to give either (Z,Z)-1,5-dihaloalkenes or (Z,E)-1,5- dihaloalkenes; dehydroxylation of benzylic alcohols and in situ generated benzylic alcohol salts with iron(III) chloride and triethylsilane to afford diarylmethanes; and, the alkenylation of allylic, benzylic, and propargylic alcohols with phenylacetylenes and titanium(IV) halide. The results of these studies strongly imply a cationic mechanism. The reaction methodology of the research described herein can be characterized …

Heats Of Solvation Of Organic Liquids In Room Temperature Ionic Liquids, Paula Jeanette Beach

Masters Theses

Ionic liquids are of potential use in industry as reusable, non-polluting solvents. Their thermochemical properties need to be known to facilitate planning of processes and experiments using these solvents. Two ionic liquids: 1-Butyl-3-methylimidazolium hexafluorophosphate ([C4mim]PF6 or [bmim]PF6) and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim]NTf2) were studied using a calorimeter. Various organic liquids were introduced into the solvents and their heats of solution were measured and tabulated. Potential effects of certain functional groups such as alcohol, amine, carboxylic acid, ketone, and aldehyde were examined as well as aromatics versus chains and saturated rings.

The Use Of Lanthanide Triflates As A Method For Reducing Ytterbium(Iii) To Ytterbium(Ii), Latasha Michelle Garrett

Masters Theses

High purity lutetium (99.999%) is employed in the manufacture of cerium-doped lutetium oxyorthosilicate. Such lutetium is in high demand because the cerium-doped lutetium oxyorthosilicate is the best gamma-detecting scintillator known. Solvent extraction is the most widely used method for separating the rare earths on an industrial scale at 99.999% purity. However, this process is time consuming and requires 80-100 separation stages. The major difficulty in pure lutetium production is the separation from the adjacent element, ytterbium. If ytterbium(III) could be reduced to ytterbium(II), this would permit a different chemistry between ytterbium(II) and the trivalent state elements, allowing a more facile …

Synthesis Of Two Thiol-Terminated Disaccharides And A Mannose-Branched Glycodendrimer, Chao Wang

Doctoral Dissertations

The glycocalix, a complex structure of lipids and glycoproteins, forms the cellular surface of all cells and serves to mediate a variety of events such as cell–virus recognition, cell–cell recognition, immunological response, metastasis, and fertilization. Moreover, the glycocalix is specific for a particular species, cell type, and developmental status. Alterations in the glycocalix have been found in association with many pathological conditions such as cancer and tuberculosis. Investigation of the interactions between the glycocalix and its associated proteins will lead to a fundamental understanding of these important processes.

Multivalent interactions are characterized by the simultaneous binding of multiple ligands on …

Advancing Data Analysis For Spectroscopic Imaging By Combining Wavelet Compression With Chemometrics, Robert Daryl Luttrell

Doctoral Dissertations

Spectroscopic imaging is a vital tool for studying heterogeneous samples such as bacteria and tissue. Its ability to acquire spatially resolved information allows for identification and classification of the various constituents within a sample. Spectroscopic imagers quickly acquire thousands to tens of thousands of spectra per measurement. These data are often arranged in the form of a 3-dimensional (3D) data cube which contains two spatial dimensions and one spectral dimension. This large amount of data is beneficial for gaining a thorough understanding about the distributions of chemical information. If too little information is measured, important chemical behavior may be overlooked. …

The Rational Design And Lithographic Fabrication Of Surface Enhanced Raman Spectroscopy Substrates, Jenny M. Oran

Doctoral Dissertations

The analytical capabilities of surface-enhanced Raman spectroscopy (SERS) reside in the performance characteristics of the SERS-active substrate. Signal enhancement observed in SERS is attributable to the presence of noble metal nanostructures on substrate surfaces. The rational design and control of variables such as shape and size, and distribution, density, and spacing of these nanostructures can lead to substrates that have greater analytical sensitivity and yield more reproducible enhancement. Through systematic control of the morphology of our SERS substrates, we have created ordered periodic arrays as well as random aggregates of nanoscale particles using electron beam lithography (EBL). A unique aspect …

Quantum Monte Carlo Simulations Of Many-Dimensional Harmonic Oscillators: A Study Of 2Nd And 4Th Order Propagators, Brent-Jon Bjorgvin Magnusson

Masters Theses

Because the Schrödinger equation cannot be solved analytically for systems larger than hydrogen, approximate solution methods must be applied to study systems of chemical interest. Quantum Monte Carlo is one of these methods. Quantum Monte Carlo simulations involve the diffusion of walkers through configuration space and necessitate the use of one of two imaginary time propagators, 2^nd or 4^th order. The choice of the propagator implemented depends on a balance between accuracy and efficiency. Obtaining accurate solutions is the primary objective; once this is accomplished, finding ways to make the simulations efficient is the next intention. Using a …

The Synthesis And Stability Of Endohedral Actinium-225(225Ac@C60), Jofa Gideon Mwakisege

Masters Theses

Due to their chemical and thermodynamic stability, fullerenes could play an important role in encapsulation of radionuclides for applications in radio-immunotherapy. In this thesis, we report the first synthesis of actinium endohedral fullerenes. The alpha-emitter Actinium-225 (²²⁵Ac, t_1/2 =10 d) was trapped in fullerenes by the direct current (D.C) arc discharge-catcher method in a He atmosphere. Endohedral ²²⁵Ac and the bulk of fullerene C₆₀ was dissolved from the catcher electrode (a Pt disk covered with a thin layer of C₆₀) in toluene under N₂, and converted to the malonic ester derivative. …

Novel Approaches To Prepare And Utilize Sers Substrates: Multiplex Microfluidics And Nanotransfer Printing, Nahla A. Abu-Hatab

Doctoral Dissertations

Over the past few decades, surface enhanced Raman spectroscopy (SERS) has garnered respect as an analytical technique with significant chemical and biological applications. SERS is important for the life sciences because it can provide trace level detection and a high level of molecular structure information. The development of quantitative, highly sensitive substrates requires control over size, shape, and position of metal nanoparticles which function as the SERS active medium. Thus, creating and successfully implementing a sensitive, reproducible, and robust SERS active substrate continues to be a challenging ask. Its future development depends critically on techniques for lithography and nanofabrication. Herein, …

Approaches To Generating Selectivity In Microcantilever Sensors, Peter J. Chapman

Doctoral Dissertations

Microcantilever (MC) sensors have emerged as sensing transducers that offer greater sensitivity than comparable sensors due in large part to their very small dimensions. MCs have been utilized in many chemical sensing applications. Not only do MCs demonstrate greater sensitivity, but they also are relatively low in cost, they can be used in an array format, and they can be integrated into on-chip electronic circuitry.

While MC sensors demonstrate great sensitivity, an area of weakness that MC sensors must overcome is that of selectivity. The response of a MC sensor to analyte is mechanical; these mechanical responses lack the information …

Materials Chemistry Of Nanocubes And Mesoporous Silicas: Characterization And Adsorption Studies, Sami Ziad Chanaa

Doctoral Dissertations

Metal oxides (MO) and their surfaces play a vital role in numerous phenomena, including metal surface passivation, catalysis, integrated optoelectronic technology, and pollution monitoring via solid-state gas sensing. This experimental study seeks to aid in the development of accurate and predictive theoretical models of the potential energy surfaces described in the interaction of these small molecules with the magnesium oxide (MgO) substrate. MgO, with its structural simplicity and capacity to be fabricated with a predominantly (100) exposed face, is an ideal representative of the MO family popular for both experimental and theoretical studies. Using high-resolution volumetric adsorption isotherms, a thermodynamic …

Establishment Of A Structure-Activity Relationship In Heterogeneous Titanosilicate Catalysts For Olefin Epoxidation Via A Building Block Method, Geoffrey T. Eldridge

Doctoral Dissertations

The non-aqueous building block (NABB) method is a synthetic method that has the goal of producing atomically dispersed, well-defined, single-site heterogeneous catalysts. The active sites of these catalysts are able to be structured on the nanometer scale using the process of sequential additions. The method is designed in such a manner that it should be able to produce a series of catalysts each with a unique, well-defined, single active site. This series of catalysts can then be used to elucidate the structure-activity relationship for the active site in a particular chemical reaction.

In this dissertation a new building block, …

Synthesis, Characterization, And Applications Of Responsive Polymer Brush-Grafted Particles, Dejin Li

Doctoral Dissertations

In this dissertation, I present the synthesis, characterization, and applications of responsive polymer brush-grafted silica/crosslinked polymeric particles. The polymer brush-grafted particles were synthesized by surface-initiated "living"/controlled radical polymerizations from initiator-functionalized particles in the presence of free initiators. Two types of core particles were used in my research. One was silica particles, which were synthesized by Stöber method. The other one was crosslinked PtBA particles, which were prepared by seeded emulsion polymerization. The responsive properties of the grafted polymer brushes were characterized with ¹H NMR and Dynamic Light Scattering.

The Utilization Of Microwave Irradiation In Organic Synthesis: Organotrifluoroborate And Alumina Chemistry, Arie A. Dadush

Masters Theses

The utilization of microwave irradiation in chemistry started in the 1950’s. Due to operational difficulties, organic chemists only began using microwaves in the mid- 1980’s, when better instruments were invented. This work describe the utilization of microwaves in two areas of organic chemistry: microwave enhanced reactions using organotrifluoroborates and microwave irradiation reactions catalyzed by highly acidic alumina.

In part one, a basic understanding of microwave irradiation is presented followed by the exploration of three major reactions. The first comprises the coupling of allyl acetate and cinnamyl acetate with various substituted potassium arylvinyltrifluoroborates to produce a variety of 1,4-dienes. The second …