Chemistry Commons^™

Analysis Of The Potential For Plant Uptake Of Trichloroethylene And An Assessment Of The Relative Risk From Different Crop Types, Roy-Alan C. Agustin

Theses and Dissertations

This research expands our limited knowledge on the influence of plants on the fate and effects of trichloroethylene (TCE), providing a screening tool on which to base decisions regarding the need for actual sampling of plants. First, physicochemical properties of TCE--vapor pressure, Henry's Law constant, water solubility, octanol-water partition coefficient, molecular weight, and half-life--were screened against relationships reported in literature to evaluate TCE plant uptake potential. This screening approach indicated TCE may be transferred to plants via retention by root surfaces, root uptake and translocation, and foliar uptake. Next, the PLANTX model developed by Trapp and others was applied to …

Vadose Zone Contamination Measurement And Modeling, Thomas A. Reeder

Theses and Dissertations

This thesis investigated the effects of the slow sorption mechanism on the transport of volatile organic contaminants in the vadose zone. Recent research has shown that slow sorption may have a significant impact on the transport of volatile organic compounds in the subsurface. Specifically, this document examined the effects of slow sorption on the Vapor Extraction System (VES) and the Purge and Trap Measurement System. It was found that the slow sorption of organic molecules on soil may profoundly influence the efficiency of VES and purge and trap. In addition, this thesis investigated possible alternatives to purge and trap, including …

Development Of A System For Survey Of Radon Concentration Of The Dayton Area Using A Liquid Scintillation Counter And Analysis Of The Data, Taewon Kim

Theses and Dissertations

A system to do a large scale survey was developed. The data obtained from the survey was analyzed using a database. The database incorporated an equation for converting cpm into radon concentration pCi/ℓ). The equation of conversion, protocol for measuring radon concentration, survey form, and a database program were modified (from previous theses) or developed for this thesis. The elution time constant, adsorption time constant, and calibration factor were calculated for equation of conversion. Two surveys were during the course of the thesis. On the first survey, the arithmetic average radon concentration with standard error of the mean was 2.9 …

Resonance Raman Spectra Of Chloroperoxidase Reaction Intermediates, Ann Marie G. Sullivan

Theses and Dissertations

Chloroperoxidase is an enzyme that exhibits spectroscopic and structural properties similar to cytochrome P-450. Chloroperoxidase is studied using resonance Raman spectroscopy to characterize the reaction intermediates of the physiological mechanism, known as compounds I and II. Compound I is formed by a two electron oxidation of the resting enzyme and contains an Fe(IV) porphyrin ℼ cation radical. A one electron reduction of compound I produces the compound II intermediate which contains an oxy-ferryl [Fe(IV)=O] iron heme.

Chloroperoxidase is a heme enzyme of substantial interest because of its structural similarity to cytochrome P-450 and because of its diverse reactivity. Chloroperoxidase can …

An Assessment Of The Accuracy Of Semi-Empirical Quantum Chemistry Calculations Of The Mechanical Properties Of Polymers, James R. Shoemaker

Theses and Dissertations

The ultimate mechanical properties of polymers, assuming perfect morphology, will be limited by the mechanical properties of a single, ideal polymer chain. Previous calculations of polymer chain moduli using semi- empirical (SE) quantum chemistry methods have resulted in modulus values much higher than experimentally measured. This study investigated the error in the calculated inherent to the method of calculation by comparing SE results for C-C bond potentials in two well characterized polymers, polyethylene and polydiacetylene. It was found that the SE calculation systematically overpredicted bond stiffness in these polymers by approximately 25% to 30%. This is the upper limit on …

Imide/Arylene Ether Copolymers, Brian J. Jensen

Theses and Dissertations

Three different series of imide/arylene ether block copolymers were prepared using two different imide blocks and two different arylene ether blocks. Block molecular weights studied were 3110 and 6545 g/mole for each block and all four combinations possible were prepared in each series. Also, several segmented copolymers were prepared by forming the imide segment and the copolymer in the presence of the pre-formed arylene ether block.

Two amine-terminated poly(arylene ether) blocks (ATPAE) were prepared by reacting 1,3-bis(4-fluorobenzoyl)benzene with either 2,2-bis(4-hydroxyphenyl)propane (BPA) or 9,9-bis(4-hydroxyphenyl)fluorene (BPF) and 4-aminophenol. Two anhydride-terminated poly(amic acid) blocks were prepared by reacting 4,4'-oxydianiline (ODA) or 1,3-bis(4-aminophenoxy-4’- benzoyl)benzene …

Reactions Of Substituted Pyridinium Salts With Cyanide; Formation And Metal Complexes Of 2,2'Bis (Hydroxymethyl)-4,-4'Bipyridine, Dorothy N. Eseonu

Theses and Dissertations

The unique combination of properties of bipyridinium salts and their use in biological systems, chemical reactions, and as herbicides in agriculture have made them a discovery of major international importance. The controversy about the position of attack of the cyanide ion on the pyridine ring and the discovery of the formation of unsubstituted bipyridinium salts from the reaction of pyridinium salt with cyanide ion opened a new area of research. The current work involved a study of reactions of substituted pyridinium salts with cyanide ion. The substituted pyridinium salts were prepared by the literature methods. The 2- and 3- cyanopyridinium …

Development Of Solid Substrate Luminescence And Chromatographic Techniques For Chemical Analysis, William J. Long

Theses and Dissertations

Room Temperature Phosphorimetry (RTP) is a sensitive and selective technique which is well suited to the analysis of compounds of environmental and pharmaceutical interests. Absolute sensitivity is generally in the low to subnanograrn range. Selectivity of this technique is due to the fact that only several hundred compounds phosphoresce at room temperature. In these studies attempts are made to gain a greater understanding of the phenomenon of solid substrate room temperature phosphorimetry and to extend the application range of the technique.

This goal is approached through several directions, all leading to a greater understanding of solid substrate luminescence in general, …

Electrochemical And Surface Enhanced Resonance Raman Study Of Heme Proteins At Bare Metal Electrodes, David Edward Reed

Theses and Dissertations

Direct heterogeneous electron transfer reactions between horse heart cytochrome g_and silver electrodes were investigated by electrochemical and spectroelectrochemical methods. The kinetics of these reactions were established as being quasi-reversible, with a formal heterogeneous rate constant (k°'s,h) ranging between 0.18 - 1.5 x 10^-3 cm/s, for both polished and electrochemically roughened silver surfaces. Such reactions were stable and reproducible for over ten hours at room temperature. These results clearly demonstrate that neither electrode surface modification nor the inclusion of mediators is necessary to study electron transfer reactions of heme proteins at metal electrodes.

A crucial factor in obtaining the quasi-reversible …

A Study Of The Heterogeneous Electron Transfer And Dioxygen Binding Reactions Of Myoglobin, Bertha Bauer Cosby King

Theses and Dissertations

Quasi-reversible electron transfer kinetics are reported for sperm whale myoglobin reacting at tin-doped indium oxide electrodes. This reaction was studied by three different electrochemical or spectroelectrochemical methods; cyclic voltammetry (CV), single potential step chronoabsorptometry (SPS/CA) and derivative cyclic voltabsorptometry (DCVA). Kinetic parameters were determined from experiments which followed the purification of the protein,

the pretreatment of the electrode surface, and the removal of dioxygen from the sample solution. A formal heterogeneous electron transfer rate constant, k0′, of 2.6 (±0.5) x 10-5 cm/s and a transfer coefficient, α, of 0.48 (±0.05) were obtained using SPS/CA. These results are shown to correlate …

The Synthesis And Characterization Of Some Thermally Stable Polypyrazoles And Acetylene Terminated Aspartimides, John W. Connell

Theses and Dissertations

Reactions involving the nucleophilic addition cyclization to activated acetylenes have been employed as a novel route to moderate to high molecular weight polymers. Polypyrazoles (PI to P12) have been prepared from the Michael-type addition cyclization of various aromatic dihydrazines to aromatic dipropynones in m-cresol. The aromatic dihydrazines employed were 4, 4'-dihydrazinodiphenyl ether (4,4' -DHDPE), 4,4 '-dihydrazinodiphenylmethane (4, 4'-DHDPM), and 4, 4' -dihydrazinodiphenyl sulfone (4,4'-DHDPS). The dipropynone sutilized were 1,1’- (1,4-phenylene) bis (3-phenyl- 2-propyn-l-one), (l,4 -PPPO), 1,1’ - (1, 3-phenylene) bis (3 -phenyl- 2 -propyn-l-one), (1,3-PPPO), 1,1 '-(1,4 -phenylene) bis (2 -propyn- l-one), (1,4 -PPO), and 1,1’- (1,3 -phenylene) bis (2 …

Electrochemical Investigation Of The Effects Of Temperature, Ph, And Electrolyte On The Electron Transfer Reactions Of Cytochrome C, Kent Brian Koller

Theses and Dissertations

Spectroelectrochemical and electrochemical methods have been used to investigate the characteristics of heterogeneous electron transfer between cytochrome c and indium oxide electrodes. Direct electron transfer between cytochrome c and solid electrodes is of interest due to the interfacial character of electron transfer between the protein and its membrane-bound physiological redox partners. The conformation of ferricytochrome c is affected more by changes in temperature or pH than is its reduced form, ferrocytochrome c. This difference in conformational stability is attributed to the +1 charge of the heme in ferricytochrome c that is largely embedded in the hydrophobic interior of the enzyme. …

Chemical Studies On Oxomolybdenum(Vi,Iv) Complexes As Bioinorganic Models For The Molybdenum Oxidases, James Thomas Lyon Iii

Theses and Dissertations

The synthesis, characterization, and chemical properties of Mo(VI)o₂(5-X-SSP) and Mo(VI)o₂(5-X-SSE), (5-X- SSP²- = 2-((5-X-salicylidene)amino)benzenethiolate; 5-X- SSE^2- = 2-((5-X-salicylidene)amino)ethanethiolate; X = Br, Cl, H, CH₃O), which contain tridentate (ONS) Schiff base ligands is described. The chemical properties of these molybdenum complexes are compared with those which possess tridentate (ONO) Schiff base ligands. Cyclic voltammetry was used to obtain cathodic reduction potentials (E_PC) for the quasi-reversible reduction of the cis-dioxomolybdenum (VI) complexes. Although the reductions are quasi-reversible, trends are observed in E_PC both within series and when different series are …

Effects Of N-Substituents On The Polymerization Properties Of Maleimide, Dilip R. Abayasekara

Theses and Dissertations

The effect of the amide function and the carbethoxy function on the polymerization properties of maleimide are reported. The effects of these functions on homopolymerization and copolymerization (with styrene) were examined. These electron-withdrawing groups appeared to decrease the rate of homopolymerization and increase the rate of copolymerization.

N-carbamylmaleimide and N-carbethoxymaleimide were copolymerized with styrene in 1,4 -dioxane at 60.0° C at different feed ratios to high conversion. Copolymer composition, determined by elemental analysis and 1H NMR, indicated that while 1:1 copolymers were obtained with an equimolar feed ratio, the two systems were not alternating. It is of note that the …

Synthesis Gas Conversion With Zs M-5 Supported Ruthenium Catalysts, Robin Elizabeth Young Eaton

Theses and Dissertations

Some bifunctional ZSM-5 supported ruthenium catalysts (Ru/ ZSM-5) were prepared by an extraction technique employing Ru ₃(C0)₁₂ • The weight percentage Ru ranged from approximately 1% to 8% Ru as determined by Atomic Absorption Spectroscopy. Characterization data employing Infrared (IR) Spectroscopy, X-ray Powder Diffractometry (XRPD), X-ray Photoelectron Spectroscopy (XPS/ESCA), Ion-Scattering Spectrometry (ISS) and Chemisorption were obtained for the catalysts. The data indicated the presence of highly dispersed Ruo₂ particles of less than 60 A on the surface of the as-prepared (AP) catalysts. Calcination of the AP catalysts at 500°C for 24 h increased the particle size of …

Electrochemical Determination Of The Heterogeneous Electron Transfer Kinetics Of Soluble Spinach Ferredoxin, Charlene D. Crawley

Theses and Dissertations

The application of electrochemical techniques to biological systems has become an attractive method for characterizing the redox and electron transfer behavior of biomacromolecules. This study focuses on the role of soluble spinach ferredoxin (Fd) in photosynthesis where it functions as an electron carrier to membrane bound species in the plant chloroplast. An electrochemical model is used where in Fd now serves as a soluble redox species which undergoes oxidation and reduction via electron transfer at an electrode. This type of model is significant in that both the membrane and electrode reactive sites are characterized by charged bilayer interfacial regions which …

Interfacial Electrochemistry Of Cytochrome C And Myoglobin, Edmond F. Bowden

Theses and Dissertations

The interfacial electrochemistry of horse heart cytochrome c was studied at metal and metal oxide electrodes. Sperm whale myoglobin reactions at metal oxide and surface modified electrodes were also investigated. Emphasis was on the measurement and mechanistic interpretation of the heterogeneous electron transfer kinetic parameters for these electrode reactions.

The motivation for this study stems from the fact that some electron transfer proteins, e.g., cytochrome c, transfer electrons heterogeneously in physiological systems. Specific electrodes may, therefore, serve as suitable models for physiological surfaces. Electrode and membrane interfaces are both electrically charged and both have oriented hydration water layers.

The cyclic …

Direct Determination Of Pentachlorophenol By Differential Pulse Polarography, Albert L. Wade

Theses and Dissertations

Concern over environmental contamination leading to the introduction of pentachlorophenol into human and animal systems has resulted in the need for a rapid and direct method for determining trace concentrations of this highly toxic compound. A direct electrochemical procedure has been developed for determining trace conccentrations of this phenol dovm to 0.27 ppm. This method uses the electrochemical techniques of differential pulse polarography at the dropping mercury electrode, and differential pulse voltammetry at the carbon paste electrode to reduce pentachlorophenol for this determination. Cyclic voltammetry at the hanging mercury drop electrode has been used to characterize the reaction behavior of …

High Pressure Liquid Chromatographic Methods For The Separations Of Derivatized Alpha-Keto Acids And Thiamine Phosphate Esters, Bruce Clark Hemming

Theses and Dissertations

Improved methods have been developed for separation of a-keto acid derivatives and for thiamine and its phosphate esters. Linear gradient reverse phase chromatography using ion-pair formation provides baseline resolution for a seven-component homologous series of a-keto acid dinitrophenylhydrazones having increasing carbon chain lengths. Branched-chain keto acids can also be separated. Aldehyde derivatives were examined as possible interfering compounds. Peak identification in biological material was confirmed for pyruvate by an enzymic peak shift technique. Monitoring near 365 nm permits low nanogram detection. Preliminary studies of keto acids in biological material illustrate the method's applicability. The same system with slight changes separates …

The Synthesis Of Novel Macrocyclic Multidentate Compounds From Dioxodioic Acids (1), R. Elliott Asay

Theses and Dissertations

A series of novel macrocyclic multidentate crown compounds have been prepared from a series of dioxodioic acids. The dioxodioic acids were prepared by treating various oligoethylene glycols or amines with maleic, succinic, citraconic, and glutaric anhydrides. The crown compounds were then synthesized from the dioxodioic acid chlorides obtained from the diacids and various oligoethylene glycols or ethylene diamine.

Real-Time Computer Optimized Scanning Potential Coulometry For Multi-Component Trace Analysis, Norman W. Petty

Theses and Dissertations

The instrumentation and methodology for real-time computer controlled scanning potential coulometry for multi-component trace analysis is described. The sensitivity limit was determined to be 10^-8 F for electrochemically reversible constituents. The sensitivity limit could be extended if measures were taken to compensate for the periodic signal found on the electrolysis current. Non-linear least squares curve fitting methods accurately resolved iron-platinum and silver-iron interferences to give accurate determinations for iron and silver. The resolving capability of this method was tested using theoretically generated scanning potential coulograms. The computer resolved sample constituents with a 1 to 100 concentration ratio and a formal …

A Photochemical Study Of S-Triazolo[4,3-B] Pyridazine And 3-Diazo-4-Oxo-3,4-Dihydroquinoline, John Timothy Carlock

Theses and Dissertations

When subjected to ultraviolet radiation in the presence of an alkene, s-triazolo[4,3-b]pyridazine (STP) undergoes an unusual 3 + 2 photocycloaddition wherein the alkene adds to the 1 and 8 positions of STP with concommitant N4-N5 bond cleavage yielding 5,6-disubstituted-6,7-dihydro-7-methylene (and 7-cyanomethyl)-5H-pyrrolo[1,2-b]-s-triazoles. Amides and esters of indole-3-carboxylic acid have been synthesized by a novel reaction employing the ultraviolet irradiation of 3-diazo-4-oxo-3,4-dihydroquinoline (QDA) in the presence of amines or alcohols respectively. QDA, when irradiated, is postulated to undergo an internal Wolff Rearrangement to Indole-3-ketene which can add any amine or alcohol to form the corresponding amide or ester in modest to good …

The Dependence Of The Apparent Pk Of Ion Exchange Celluloses Of Ionic Strength, Paul Cyril Gillespie

Theses and Dissertations

Diethylaminoethyl cellulose was titrated with acid and base in various concentrations of NaCl. The pK values were determined from titration curves using a graphical technique. Two titratable groups were observed from the acid titration curve, a major and a minor group. The minor group, which represented 20% of the acid titration, was barely detectable in the base titration curve and had a salt-independent pK of 6.0. The pK of the major group was strongly salt-dependent and was approximately a linear function of log N NaCl. An equilibrium shift caused by the counter ion may explain the salt dependence. Hydrogen bonding …

The Effects Of Ultrasonic Vibration, Tension And Torsion On The Charge Acceptance Of The Alkaline Silver Electrode ; Ii. Potentiostatic Studies Of The Oxide Growth Rate Law For The Alkaline Silver Electrode ; Iii. The Determination Of Ionic Transport In Silver Oxide Using Radiotracer Techniques With Ag[Superscript 110m], Reed Harold Chase

Theses and Dissertations

The effect of ultrasonic vibration on the anodic oxidation of silver foil in KOH was studied. An increase in charging capacity of approximately 20% was found to be the result of cavitation erosion. Silver wire was exposed to tension and torsion during oxidation but no change in charge acceptance was caused by these stresses. The oxide growth rate on silver foil electrodes was compared to rate equations that have been proposed for other metals. Uhlig's equations for the growth of semiconductor oxides was found to describe most of the data. The data did not fit other rate equations. Determination of …

Voltammetric And Electrochemical Kinetic Studies Of The Halides And Halogens At A Platinum Rotating Ring-Disk Electrode In Anhydrous Acetic Acid, Donald Harrison Cranney

Theses and Dissertations

The electrochemical behavior of the iodine-iodide couple was investigated in both basic and neutral acetic acid solutions at a platinum rotating ring-disk electrode. Voltammetric curves were obtained and discussed. Various kinetic parameters were determined and by comparing to theoretical kinetic parameters a probable reaction mechanism was deduced. The mechanism that best fit experimental results is the following I- + S = I(S) + e- I(S) + I- = I2 + S + e (slow). The electrochemical behavior of bromine, bromide, and chloride was also investigated in the same media. Voltammetric curves were recorded and discussed with emphasis on the hysteresis …

A Study Of Selected Photo Fries Rearrangements, Elwood Lloyd Loveridge

Theses and Dissertations

The Fries rearrangement of phenyl esters is reviewed and compared to the reaction when light is the source of energy. The products are different due to different mechanism of reaction. Light energy causes either free radical or concerted reactions. The S-phenylthiol esters and anilides were studied also. Although many of the rearrangements are the same, we did not see any alkyl migration nor decarboxylation type reactions with either the sulfur or nitrogen compounds. Three papers have been published from this work: Bradshaw, J. S., Knudsen, R. D. and Loveridge, E. L., J. Org. Chem., 35, 1219 (1970); Bradshaw, J. S., …

A Comparison Of Free Radical Detection Methods, Danny Kiang-Wah Pan

Theses and Dissertations

The methods used for free radical detection are chemical titration, spectrophotometry, Gouy magnetic measurements and NMR shift technique. The free radicals chosen for this study are Fremy' s salt (ON(SO_3 )K_2),2,2-diphenyl-1-picryl hydrazyl (DPPH) 3-carbamoyl-2,2,5,5-tetramethylpyrrolidin-1-yloxy (CTM-pyrrolidin), 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-yloxy (CTM-pyrrolin), 4-acetamido-2,2,6,6-tetramethylpiperidino-1- oxyl (ATMP) and galvinoxyl. The detectable range for each method is given. The NMR method is a fast and convenient method for the magnetic susceptibility determination of a sample in solution, with. accuracy up to ± 1%.

The Intermolecular Potential And Vibrational Relaxation Of The Ar-Co System, Gregory Allen Parker

Theses and Dissertations

The angle, distance and vibration dependence of the Ar-CO intermolecular potential is calculated using the electron gas model to obtain the short range interaction which is smoothly joined onto the long range van der Waals tail which is obtained from accurate C_6, C_7, and C_8 coefficients. Our calculated second interaction virial coefficients are compared with experiment and with a simple adjustment of the Ar-CO potential an excellent agreement is obtained. Our spherically averaged potential is also in excellent agreement with a spherical potential inferred from high energy scattering data. Simplified expressions for the scattering amplitude and differential cross section are …

A Potentiometric Method, A Convenient And Rapid Technique For Determination Of The Thermodynamics Of Ionization Reactions For Water, Weak Acids, And Some Slightly Soluble Salts In Aqueous Organic Mixed Solvents, Charanai Panichajakul

Theses and Dissertations

A potentiometric method which is devised to be rapid and convenient for determining ionization constants for water, weak acids (or bases), and certain solids in mixed solvents is described. The method has been applied to the determination of ionization for water, acetic acid, benzoic acid, and phenol and the solubility product constant for silver chloride in mixtures of water with methanol, ethanol, acetone, tetrahydrofuran, and p-dioxane containing from 0 to 70 mass percent organic co-solvent at several temperatures between 10 and 40°C. Results are used to study the thermodynamics of ionization in each mixture which is discussed relative to various …

Solid-Liquid Phase Equilibria In Systems Of (I) Para-Xylene, (Ii) Mesitylene, And (Iii) N,N-Dimethylformamide ; Excess Volume Determination In Systems Containing Cyclohexane ; Calculations Of Activities For The N-Hexane + Cyclohexane System, John F. Moellmer

Theses and Dissertations

Solid-liquid phase equilibria studies were used to investigate possible compolllld formation in solutions of (i) para-xylene, (ii) mesitylene, and (iii) N,N-dimethyl-formamide (DMF) with mono- and di- halobenzenes that were selected to give a wide range of acceptor properties. Solid 1:1 intermolecular compounds were identified from solutions of p-C_6H_4F_2 with mesitylene, p-C_6H_4Br_2 with p-xylene, and p-C_6H_4Cl_2 with p-xylene. The results suggest that compound formation occurs because of favorable geometry rather than a charge transfer process. A vibrating tube densimeter was used to determine, with high precision, the densities and subsequently excess volumes of mixing of the n-hexane plus cyclohexane system. Temperature …