PART I. A deuterium exchange analysis of 2,5-dihydroxyacetanilide (5) in the absence and presence of DHAE II was performed to test the nucleophilicity of the substrate in the absence and presence of catalyst. In addition, inhibition studies using 1,4-dihydroxybenzene were performed to determine the role that the N-acetyl side chain group plays in the formation of a stable substrate-enzyme complex. 1,4-Dihydroxybenzene was found to be a weak inhibitor, indicating that the N-acetyl functionality may play a crucial role in forming stable enzyme-substrate interactions. The synthesis of dihydroquinoline 7 was pursued to investigate the enzyme substrate interactions between DHAE and a substrate where the N-acetyl side chain has been fixed to a particular orientation. Efforts towards formation of the C6-C7 bond as a key step in the synthesis of dihydroquinoline 7 using palladium couplings, organocuprates, Lewis acid catalysts, and aza-Claisen reactions were pursued. To complement the results obtained, the electron distribution in amide 21 was calculated using Semi Empirical methods. The results revealed that the electron density in the aromatic ring is centered around C4, suggesting that this is the most nucleophilic carbon in the ring. PART II. Slagenins A (1), B (2), and C (3) were synthesized by β-functionalization of olefin 14. The desired tetrahydrofuroimidazolidin-2-one system was achieved by intramolecular oxidative addition of alcohol 4 to the imidazolone ring. When this reaction was carried out in the presence of methanol slagenins B (2) and C (3) were obtained in good yield. Heating 2 and 3 in aqueous acid gave slagenin A (1) as the sole product. (Z)-debromoaxinohydantoin (17) was synthesized by intramolecular cyclization of α-methoxy imidazolone 11b under acidic conditions followed by a double oxidation reaction to furnish the hydantoin-lactam functionality. These conditions were originally developed for a practical synthesis of the related alkaloid (Z)-debromohymenialdisine (20). A series of acid and base catalyzed reactions of imidazoles bearing an α-β unsaturated system or a β-halogen functionality showed that cyclizations via an S[subscript N]2 path favor formation of an oxazoline ring system. Preliminary studies using pyrrolocarboxamideacetals suggest that β-ketone 73 would be an appropriate substrate for the formation of the pyrrolopyrazine system in the agelastatins. / Graduation date: 2002

In situ reduction of hydrido-tris-(3,5-dimethylpyrazolyl)borato(trioxo) rhenium(V) with triphenylphosphine or triethylphosphite leads to a reactive rhenium(V) species that catalytically deoxygenates epoxides at 75-105��C. The reaction is stereospecific, except for trans- and cis-butene oxide which formed minor amounts of the opposite isomer. A variety of different functional groups were tolerated and even epoxides that reacted slowly could be pushed to greater than 95% conversion given extended time and/or higher temperature. The absence of clustering processes shows how the choice of ligand can have a major influence on the design of the catalytic cycle. The rhenium(V) species formed from reduction of Tp'ReO��� was identified as Tp'Re(O)(OH)���. Tp'Re(O)(OH)��� reacted with ethanol and HCl to form ethoxide and hydroxo chloride complexes, respectively. In addition, Tp'Re(O)(OH)��� was an excellent catalytic and stoichiometric reagent for the deoxygenation of epoxides and sulfoxides. Loss of water from Tp'Re(O)(OH)��� to form the catalytically active species Tp'Re02 was shown to be a necessary preequilibrium process. The kinetic behavior of the catalytic system is complex. First-order behavior in [Re][subscript T], zero-order dependence in [PPh���] and saturation behavior for epoxide were observed. The reversible formation of a coordinated epoxide complex was proposed to explain the saturation behavior. The epoxide complex was shown experimentally and computationally to engage in two separate reactions: ring expansion to form a syn-diolate complex, and direct fragmentation to alkene and trioxide. A steady-state concentration of diolate is eventually reached explaining a "burst" of alkene production prior to generation of a pseudo-zero-order catalytic system. The diolate formed is the syn-isomer, which is the kinetically formed product. Direct epoxide fragmentation is the primary source of alkene. This process was determined to be four times faster than ring expansion for cis-stilbene oxide. The synthesis and characterization of a tethered-epoxide Cp* rhenium trioxide complex has been achieved. Reduction of this complex leads to an unsaturated rhenium(V) species that is immediately complexed by the tethered epoxide. Experimental data and molecular mechanics modeling support intramolecular coordination of the epoxide to the rhenium center. These results confirm that the coordinate epoxide is a viable intermediate in rhenium-catalyzed epoxide deoxygenations. / Graduation date: 2003

Graduation date: 2002

Thesis (M.S.)--Ohio University, June, 2006. / Title from PDF t.p. Includes bibliographical references (p. 63-71)

No description available.

This work is mainly focused upon the preparation, processing and evaluation of mechanical and material properties of epoxy/single walled carbon nanotube (SWCNT) nanocomposite thin films. B-staged epoxy/SWCNT nanocomposite thin films at 50% of cure have been prepared for improving conductivity and mechanical performance of laminated composites. The SWCNTs were functionalized by oxidation and subsequent grafting using polyamidoamine generation 0 dendrimers (PAMAM-G0). The epoxy nanocomposites containing SWCNTs were successfully cast into thin films by manipulating degree of cure and viscosity of epoxy. The first section of this study focuses on the covalent oxidation and functionalization of single-walled carbon nanotubes (SWCNTs), which is necessary in order to obtain the full benefit of the SWCNTs inherent properties for reinforcement. In the second section of this work the preparation of B-staged epoxy/SWCNT nanocomposite thin films is discussed and what the purposes of thin films are. Additionally, the morphology as well as mechanical properties is evaluated by numerous means to obtain a clear picture as to the mechanisms of the epoxy/SWCNT nanocomposites. Furthermore, the effects of using sulfanilamide as a more attractive surface modifier for improved dispersion and adhesion and the effects of nylon particles for improved toughening on epoxy/SWCNT nanocomposites are discussed which displays improvements in numerous areas. Finally, based on these findings and previous studies, the B-staged epoxy/SWCNT nanocomposite thin films can be seamlessly integrated into laminated composite systems upon heating, and can serve as interleaves for improving conductivity and mechanical strengths of laminated fiber composite systems.

The production of sand can be a major issue in many young, unconsolidated sandstone formations where there is little to no cement holding the individual sand grains together. When such reservoirs are produced, quite often operators face problems with reduced well productivity and equipment failure. Because of these issues, the industry has developed numerous techniques in its effort to control formation sand production. Sand consolidation is one technology that has been studied and used since the 1940s. The theory behind sand consolidation technology is to place a liquid material which will create a grain to grain contact that will bind individual sand grains together. Most consolidation treatments contain a preflush to clean and wet the surface, the consolidating system to bind the sand grains and give residual strength, and, finally, an overflush to ensure the formation is still able to produce fluids. With the successful placement of this fluid, the sand grains will be locked in placed so that they will not be produced. The technology has gone through many phases of conception since the 1940s; however, most consolidation material that is pumped in the past has been based upon an epoxy or furan backbone. While there are many technologies available, for the purpose of my research, the epoxy technology was experimentally investigated. The testing of the fluid involved investigating numerous additives to obtain the correct residual strength of the sample, as well as the necessary retained permeability. For the epoxy fluid, the optimal preflush, epoxy system and overflush formulations were determined after 250 checkout tests. Based upon these tests, the fluid was optimized to its working time and UCS results. The optimal system included the addition of PA2 to the preflush, along with PA1 and an aromatic amine curing agent to the epoxy system. PA1 and PA2 are adhesion promoter additives which were deemed necessary as a result of the testing. This system was then tested further in a HP/HT cell. While there is still room for improvement with respect to retained permeability, the system still performs very well in terms of UCS.

Differential scanning calorimetry (DSC), 13C solid state nuclear magnetic resonance (SSNMR), one- and two-dimensional fourier transform infrared spectroscopes (FT-IR), Gel Permeation Chromatography (GPC) have been used to investigate the miscibility behavior and specific interactions of Poly(3-hydroxybutyrate), (PHB) blending with poly(styrene-co-vinyl phenol), (PS-co-PVPh) through hydrogen bonding complex upon varying the vinyl phenol contents in copolymer. We describe FT-IR spectra reveal that hydrogen bonding between carbonyl and phenol. A miscibility window exists when the vinyl phenol fraction in the copolymer is greater than 20 mol% in the PHB/PS-co-PVPh blend system, as predicted using the Painter¡VColeman association model. The vinyl-terminated benzoxazine (VB-a), which can be polymerized through ring opening polymerization, was synthesized through the Mannich condensation of bisphenol A, formaldehyde, and allylamine. This VB-a monomer was then blending with epoxy resin, followed by thermal curing concurrently, to form epoxy/VB-a copolymers network. To understand the curing kinetics of this epoxy/VB-a copolymer, dynamic differential scanning calorimetry measurements were performed by Kissinger and Flynn-Wall-Osawa methods. The FTIR analyses revealed the presence of thermal curing reactions and hydrogen bonding interaction of epoxy/VB-a copolymers. Meanwhile, the significant enhancement of the ring opening and allyl polymerizations of the epoxy was observed. For these IPNs, DMA and TGA results indicate that the thermal properties increase with the increase of VB-a contents in epoxy/VB-a copolymers.

Thèse doctorat : Matériaux Polymères et Composites : Villeurbanne, INSA : 2004. / Thèse rédigée en anglais. Titre provenant de l'écran-titre. Bibliogr. p. [124]-133.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 61-67).