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Thermodynamic Properties of Nonelectrolyte Solutes in Ternary Solvent Mixtures

Description: The purpose of this dissertation is to investigate the thermodynamic properties of nonelectrolyte solutes dissolved in ternary solvent mixtures, and to develop mathematical expressions for predicting and describing that behavior in the solvent mixtures. Thirty-four ternary solvent systems were studied containing either alcohol (1-propanol, 2-propanol, 1-butanol, and 2-butanol), alkane (cyclohexane, heptane, and 2,2,4-trimethylpentane) or alkoxyalcohol (2-ethoxyethanol and 2-butoxyethanol) cosol… more
Date: August 1999
Creator: Deng, Tʻai-ho
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Ligand Substitution Studies in the Tetracobalt Cluster Co₄(CO)₁₀([mu]₄-PPh₂) and Synthesis and Reactivity Studies in the Fe₂Pt and FeCo₂ Mixed-metal Clusters

Description: The kinetics of ligand substitution for CO in Co4(CO)10(mu4-PPh2) , 1, have been investigated for the ligands P(OMe)3, P(OEt)3, PPh2H, P(0-i-Pr)3, P(n-Bu)3, PPh3, P(i-Pr)3, and PCy3 over a wide temperature range.
Date: August 1991
Creator: Don, Ming-jaw
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Survey of the Solid State Conformation of Calix[4]arenes

Description: The characteristics of seventy-six calix[4]arene crystal structures derived from the Cambridge Crystallographic Database are presented. This survey is a discussion of the inter and intramolecular effects on the solid state cavity shape and molecular recognition ability of the compounds. In addition to this survey, four new calix[4]arene crystal structures are presented. The conformational characteristics of these four calixarenes are determined by a complicated array of inter and intramolecular… more
Date: August 1997
Creator: Obrey, Stephen J. (Stephen James)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Conformational Analogs of Some Phytoactive Compounds

Description: In an effort to determine if there is a specific conformational structure which is most effective at the appropriate active physiological site, the synthesis of a group of sterically restricted analogs was undertaken. A portion of the polymethylene carbon skeleton of glutaric acid was replaced by selected aromatic carbons in benzenedicarboxylic acids to produce a series of ridged conformers, and the relative plant growth regulating properties of these derivatives were determined.
Date: August 1973
Creator: Skelton, Wm. Paul
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Combined Electrochemistry and Spectroscopy of Complexes and Supramolecules containing Bipyridyl and Other Azabiphenyl Building Blocks

Description: A group of azabiphenyl complexes and supramolecules, and their reduced and oxidized forms when possible, were characterized by cyclic voltammetry and electronic absorption spectroscopy. The oxidized and reduced species, if sufficiently stable, were further generated electrochemically inside a specially designed quartz cell with optically transparent electrode, so that the spectra of the electrochemically generated species could be taken in situ. Assignments were proposed for both parent and pro… more
Date: August 1995
Creator: Yang, Lei
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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The Pure Rotational Spectra of Diatomics and Halogen-Addition Benzene Measured by Microwave and Radio Frequency Spectrometers

Description: Two aluminum spherical mirrors with radii of 203.2 mm and radii of curvature also of 203.2 mm have been used to construct a tunable Fabry-Perót type resonator operational at frequencies as low as 500 MHz. The resonator has been incorporated into a pulsed nozzle, Fourier transform, Balle-Flygare spectrometer. The spectrometer is of use in recording low J transitions of large asymmetric molecules where the spectra are often greatly simplified compared to higher frequency regions. The resonators u… more
Date: August 2010
Creator: Etchison, Kerry C.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Analysis of Acid Gas Emissions in the Combustion of the Binder Enhanced d-RDF by Ion Chromatography

Description: Waste-to-energy has become an attractive alternative to landfills. One concern in this development is the release of pollutants in the combustion process. The binder enhanced d-RDF pellets satisfy the requirements of environmental acceptance, chemical/biological stability, and being storeable. The acid gas emissions of combusting d-RDF pellets with sulfur-rich coal were analyzed by ion chromatography and decreased when d-RDF pellets were utilized. The results imply the possibility of using d-RD… more
Date: August 1988
Creator: Jen, Jen-Fon
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Chromatographic and Spectroscopic Studies on Aquatic Fulvic Acid

Description: High Performance Liquid Chromatography (HPLC) was used to investigate the utility of this technique for the analytical and preparative separation of components of aquatic fulvic acids (FA). Three modes of HPLC namely adsorption, anion exchange and reversed phase were evaluated. Aquatic fulvic acids were either extracted from surface water and sediment samples collected from the Southwest of the U.S., or were provided in a high purity form from the USGS. On the adsorption mode, a major fraction… more
Date: August 1986
Creator: Chang, David Juan-Yuan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Studies of Solvent Displacement from Solvated Metal Carbonyl Complexes of Chromium, Molybdenum, and Tungsten

Description: Flash photolysis techniques were applied to studies of solvent displacement by Lewis bases (L) from solvated metal carbonyl complexes of Cr, Mo, and W. On the basis of extensive studies of the reaction rate laws, activation parameters , and linear-free-energy-relationships, it was concluded that the mechanisms of solvent displacement reactions depend on the electronic and steric properties of the solvents and L, as well as the identities of the metal atoms. The strengths of solvent-metal bondin… more
Date: August 1990
Creator: Zhang, Shulin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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(4+2)-Cycloaddition Reactions of Ketenes; Pyranones

Description: This study deals with the (4+2)-cycloaddition reactions of 4-π electron compounds with ketenes. Chloroketenes were generated in situ from the corresponding chlorinated acid chlorides in the presence of the ketenophiles. Chloro-, dichloro- and diphenylketenes reacted with 1-methoxy-3-trimethylsiloxy-l,3-butadiene, and 2,4-bis(trimethylsiloxy)-1,3-pentadiene to yield the corresponding dihydropyrans. The dihydropyrans yielded substituted 4-pyranones on hydrolysis.
Date: August 1983
Creator: Agho, Michael O. (Michael Osarenogowu)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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The Study of Low Temperature Silene Generation

Description: The reactions of tert-butyl-, sec-butyl-, and n-butyllithium with dimethylfluorovinylsilane include addition to the double bond to give both silene and silenoid intermediates, fluorine substitution, and a novel vinyl substitution. For the tert-butyllithium reaction, product stereochemistry and trapping experiments using both cyclopentadiene and methoxytrimethylsilane show that silenes are not formed in THF. In hexane about 67% of the 1,3-disilacyclobutanes obtained arise from silene dimerizatio… more
Date: August 1985
Creator: Cheng, Albert Home-Been
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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GC/MS Analysis of Chlorinated Organic Compounds in Municipal Wastewater After Chlorination

Description: A study has been conducted for the qualitative and Quantitative analysis of chlorinated organic compounds in water. The study included the adaptation of Amberlite XAD macroreticular resin techniques for the concentration of municipal wastewater samples, followed by GC/MS analysis. A new analytical method was developed for the determination of volatile halogenated organics using liquid-liquid extraction and electron capture gas chromatography. And, a computer program was written which searches r… more
Date: August 1982
Creator: Henderson, James E. (James Edward)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Silenes and Silenoids in the Chemistry of Cyclopentadienylsilanes

Description: Evidence is presented that apparent silene products obtained from the metalation of cyclopentadienyldimethyl - chlorosilane either with tert-butyl1ithium or with methylenetriphenylphosphorane actually arise from the metalated starting material, a silenoid, rather than from a silafulvene intermediate. Trimethylmethoxysi1ane is shown to be an effective trap for dimethylsilafulvene. A new dimethylsilafulvene precursor, bis(dimethylmethoxysi1yl) cyclopentadiene, which gives high yields of dimethyld… more
Date: August 1986
Creator: Rozell, James M. (James Morris)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Synthesis of Ketene Thioacetals and Their Monosulfoxide Derivatives and the Thermal Rearrangements of Diallylic Ketene Thioacetals

Description: Ketene dimethyl thioacetal monosulfoxide was prepared in 68% overall yield in two steps starting from methylmagnesium chloride. The yield of dithioacetic acid was improved significantly by employing tetrahydrofuran as solvent and using elevated temperatures. A one-pot synthesis of ketene thioacetals from alkyl halides was developed and several ketene thioacetals were prepared by this method. Direct oxidation of ketene thioacetals using m-chloroperoxybenzoic acid provided a general route to kete… more
Date: August 1982
Creator: Kaya, Riza
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Silene Stereochemistry

Description: The reaction of tert-butyllithium with chloromethylphenylvinylsilane at low temperatures in hexane gave a 48% yield of a mixture of the five isomers of 1,3-dimethyl-1,3-diphenyl-2,4-dineopentyl-1,3-disilacyclobutane, formed by the head-to-tail dimerization of both E- and Z-1-methyl-1-phenyl-2-neopentylsilenes, along with an acyclic dimer. These were separated and their stereochemistry was established by ('1)H- and ('13)C-NMR spectroscopy. The E- and Z-silenes were also trapped as their {4 + 2} … more
Date: August 1984
Creator: Lee, Myong Euy
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Synthetic Applications of Ketene Cycloadditions Lactams and Coumarins

Description: The objective of this study was to develop new synthetical routes to natural and industrial products utilizing ketene cycioaddition reactions. The cycioaddition of diphenylketene with α,β-unsaturated imines yields (2+2) cycioaddition products, g-lactams. However, electron donating groups, such as dimethylamine, in the 4-position of the α,β-unsaturated imines result in (4+2) cycloaddition products, ∂-lactams. Dichloroketene reacted with α,β-unsaturated imines to yield (4+2) cycloaddition product… more
Date: August 1984
Creator: Shieh, Chia Hui
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Synthetic Applications of Ketene Cycloadditions: Natural and Novel Pyrethroid Insecticides

Description: A new synthetic route to natural and novel pyrethroid acids was developed utilizing ketene cycloaddition which is a significant improvement over existing syntheses. The newly synthesized pyrethroid acids were converted to pyrethroid esters and used to study structure-activity relationships. The cycloaddition of dichloroketene with 2,5-dimethyl-2,4-hexadiene yields (2+2) cycloaddition products, 2,2-dichlorocyclobutanones. The reductive removal of one chlorine atom from these cycloaddition produc… more
Date: August 1985
Creator: Ko, Jinren
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Catalytic Calcination of Calcium Carbonate

Description: The calcination of calcium carbonate in a cement or a lime kiln uses approximately two to four times the theoretical quantity of energy predicted from thermodynamic calculation depending upon the type of the kiln used (1.4 x 10^6 Btu/ton theoretical to 6 x 10^6 Btu/ton actual). The objective of this research was to attempt to reduce the energy required for the calcination by 1. decreasing the calcination temperature of calcium carbonate, and/or 2. increasing the rate of calcination at a specifi… more
Date: August 1985
Creator: Safa, Ali Ibrahim, 1953-
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Kinetics and Mechanism of Reactions of Disubstituted Octahedral Metal Carbonyls with Phosphorus Donor Ligands and Germanium Tetraiodide

Description: The kinetics and mechanism of the reactions of (tmpa)W-(CO)^ and (tmen)W(CO)^ (tmpa = N,N,N',N'-tetramethy1-1,3-diaminopropane and tmen = N,N,N1,N1-tetramethylethylenediamine) with four phosphorus donor ligands (triisopropyl phosphite, triphenyl phosphite, triphenylphosphine and "constrained phosphite", 4-methyl-2,6,7-trioxa-l-phosphabicylo[2.2.2]octane) in xylene have been investigated in detail. These reactions were found to take place by the ring-opening of the bidentate ligand in a reversib… more
Date: August 1976
Creator: Moradi-Araghi, Ahmad
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Partner: UNT Libraries
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Raman and NMR Relaxation Studies of Molecular Dynamics in Liquids

Description: Raman vibrational bands are sensitive to fluctuations in the molecular environment. Variations in the bandwidth and peak position can then be utilized to monitor molecular forces and interactions present in condense phases. Nuclear Magnetic Resonance (NMR) provides a convenient probe for the study of molecular reorientation in liquids since nuclear spin relaxation times are dependent on the details of molecular motion. Presented here is the solvent study of the Raman bandwidths and frequency d… more
Date: August 1987
Creator: Rodriguez, Arturo A. (Arturo Angel)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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