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Articles 3271 - 3300 of 3436

Full-Text Articles in Physical Sciences and Mathematics

Macrocyclic Polyether Sulfide Syntheses, The Preparation Of Thia-Crown-3, 4, 6, And 7 Compounds, Yau-Kwong Joseph Hui Apr 1974

Macrocyclic Polyether Sulfide Syntheses, The Preparation Of Thia-Crown-3, 4, 6, And 7 Compounds, Yau-Kwong Joseph Hui

Theses and Dissertations

Macrocyclic polyether sulfides have been prepared by reacting an oligoethylene glycol dichloride with a dithiol or sodium sulfide in ethanol. The following new compounds were prepared: 1-thia-(9-crown-3), 1,4-dithia-(9-crown-3), 1,4-dithia-(12-crown-4), 1,4,7-trithia-(12-crown-4), 1-thia-(18-crown-6), I,4-dithia-(18-crown-6), 1,7-dithia-(18-crown-6), 1,4,7-trithia-(18-crown-6), 1,7-dithia-(21-crown-7), 1,4,7-trithia-(21-crown-7). Four other previously reported macrocyclic polyether sulfides were also prepared. The symmetry of the nmr spectra of these compounds give added evidence for the proposed ring structures. The following subjects were presented and discussed: studies of cyclization by-products, dependence of cyclization yield on the size of the rings, high dilution principle and its application, medium-sized rings, effect of hetero-atoms on cyclization and melting point …

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The Solution Photochemistry Of Benzaldehyde In Benzene, Ethanol, And 1-Hexyne, Ronald Douglas Knudsen Apr 1974

The Solution Photochemistry Of Benzaldehyde In Benzene, Ethanol, And 1-Hexyne, Ronald Douglas Knudsen

Theses and Dissertations

The photoreactions of benzaldehyde in benzene, ethanol, and 1-hexyne have been studied. Irradiation of benzaldehyde in benzene produces benzoin (I), hydrobenzoin (II), and deoxybenzoin (III). Irradiation of benzoin (I) in this solvent results in benzaldehyde formation as well as small amounts of (II) and (III). The ethanol irradiation of benzaldehyde resulted, predominantly, in the formation of (II) with (I) formed in small amounts. The photolysis of benzaldehyde in 1-hexyne produces (I), (II), (III) cis-2-heptenophenone (VII), trans-2-heptenophenone (VIII), heptanophenone (IX), and 2-(n-butyl)- 1,4-diphenyl-1,4-butanedione (X). Mechanistic pathways for the formation of these photoproducts are discussed. Separation and characterization of cis- and trans-2- …

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A Calorimetric Study Of Metal Binding In Carboxypeptidase, Carbonic Anhydrase And Concanavalin A, Gary E. Hatch Apr 1974

A Calorimetric Study Of Metal Binding In Carboxypeptidase, Carbonic Anhydrase And Concanavalin A, Gary E. Hatch

Theses and Dissertations

The purpose of this study was to perfect a new calorimetric method for identifying and counting ionizable chemical groups on proteins. To do this, calorimetric and electrometric titrations were performed (using HCl and NaOH as titrant) on native carboxypeptidase, carbonic anhydrase and concanavalin A plus their apo and organic ligand bound derivatives. Readily identifiable endpoints were seen in the calorimetric titrations and general agreement was found between ΔH values obtained in this study and literature ΔH values of model compounds undergoing the same reaction. Imidazole groups were those most easily counted. Many assumptions had to be made, however, in concluding …

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Trace Metal Analysis Of Hair By Charged Particle X-Ray Fluorescence, George M. Allison Apr 1974

Trace Metal Analysis Of Hair By Charged Particle X-Ray Fluorescence, George M. Allison

Theses and Dissertations

A method for the trace element analysis of hair by charged particle X-ray fluorescence is presented. The validity of the method is shown by the analysis of NBS SRM 1577--Bovine Liver, obtained from the National Bureau of Standards. Excellent correlation is obtained between results from the analysis by the X-ray method and those certified by NBS. Hair samples are ashed by a low temperature oxidation process and analyzed by the X-ray method. The results from the analysis by the X-ray method are compared to those obtained from the analysis of the same hair samples by atomic absorption. Good correlation is …

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The Mormon Role In Irrigation Beginnings And Diffusions In The Western States: An Historical Geography, Kelly C. Harper Jan 1974

The Mormon Role In Irrigation Beginnings And Diffusions In The Western States: An Historical Geography, Kelly C. Harper

Theses and Dissertations

Irrigation has played an important part in the development of the Western States. Its beginnings have often been associated with the Mormon settlement in Utah. However, irrigation had its inception in the West long before the Mormons came to the Great Basin in 1847. The spatial extent of irrigation before this date included limited acreage in nearly every Western State.

Before their arrival in the Great Basin the Mormons had become acquainted with irrigation methods. Knowledge of irrigation had diffused to them primarily from the Spanish in the Southwest. Thus, they were well prepared to begin their irrigation enterprises in …

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Proposal: Pioneer Venus Orbiter Mission Magnetic Field Investigation, Edward J. Smith, Leverett Davis Jr., Douglas E. Jones, Bruce T. Tsurutani Dec 1973

Proposal: Pioneer Venus Orbiter Mission Magnetic Field Investigation, Edward J. Smith, Leverett Davis Jr., Douglas E. Jones, Bruce T. Tsurutani

Faculty Publications

The magnetic field investigation on the Venus Orbiter Mission must provide sensitive, accurate measurements of the magnetic field at all locations along the spacecraft orbit. In addition to being able to search for and measure any weak global magnetic field that may exist, the magnetometer must have the capability of measuring fields at frequencies high enough to permit a comprehensive study of the bow shock, the region between the shock and the ionopause, the expansion fan and the wake. Accurate measurements outside the interaction region must be made in order to provide necessary information concerning the configuration of the perturbing …

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Rotationally Inelastic Molecular Scattering. Computational Tests Of Some Simple Solutions Of The Strong Coupling Problem, Thomas P. Tsien, Gregory A. Parker, Russell T. Pack Nov 1973

Rotationally Inelastic Molecular Scattering. Computational Tests Of Some Simple Solutions Of The Strong Coupling Problem, Thomas P. Tsien, Gregory A. Parker, Russell T. Pack

Faculty Publications

Partial cross sections (opacity functions) for rotational transitions in atom-diatom collisions are computed in the infinite-order sudden (IOS) approximation and compared with accurate close-coupling (CC) calculations. Agreement is good in the dominant coupling (small total angular momentum J) region. Simple methods for calculating integral inelastic cross sections are discussed, and it is found that accurate cross sections can often be computed very simply, even when large numbers of channels are coupled together, by using IOS or first-order sudden (FOS) approximations for small J and CC or exponential Born (EBDW) methods for large J.

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State Of Bacterial Dna After Uptake Into The Roots Of Germinating Barley Seeds, Larry Dale Lawson Aug 1973

State Of Bacterial Dna After Uptake Into The Roots Of Germinating Barley Seeds, Larry Dale Lawson

Theses and Dissertations

Germinating barley seeds have been shown to take up Bacillus subtilis DNA labelled with 5-bromouracil and tritiated thymidine and retain the DNA in the root system without substantially degrading it. The percentage of bacterial DNA recovered from the total root DNA was independent of the amount of bacterial DNA available for uptake. Four observations indicated the stability of bacterial DNA after uptake into barley roots: (1) the bacterial DNA retained its transforming ability after recovery from the roots; (2) the labelled B. subtilis DNA showed similar CsCl density gradient patterns before uptake and after uptake; (3) most of the radioactivity …

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I. An Isothermal Titration Microcalorimeter. Ii. Importance Of Micronutrients In Nutrition. Iii. Zinc Bibliography, John Willard Gardner Aug 1973

I. An Isothermal Titration Microcalorimeter. Ii. Importance Of Micronutrients In Nutrition. Iii. Zinc Bibliography, John Willard Gardner

Theses and Dissertations

I. An isothermal titration microcalorimeter having a colume of 4 ml and capable of temerature control to ±2 x 10-5°C is described. Major components include a constant temperature water bath controlled to ±3 x 10-4°C, a platinum reation vessel, and an isothermal control circuit consisting of constant Peltier thermoelectric cooling and variable Joule heating controlled by a thermistor in an AC Wheatstone bridge circuit. The calorimeter was tested by measuring the heat of ionization of water and was found to produce data accurate to ± 0.1% where small samples are used such as in the investigation of many biological systems.

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Development Of Standard Procedures For Determination Of [Delta]G° (K), [Delta]H° And [Delta]S° Values Via Potentiometric And Calorimetric Titration Techniques, Jack Hugh Ruckman Apr 1973

Development Of Standard Procedures For Determination Of [Delta]G° (K), [Delta]H° And [Delta]S° Values Via Potentiometric And Calorimetric Titration Techniques, Jack Hugh Ruckman

Theses and Dissertations

Standard computer techniques were developed for computation of ΔG° values from potentiometric titration data and ΔH° values from calorimetric titration data. The procedures developed can be used for any systems having the general equations HA = W^+ + A^- ; H_2A = 2H^+ + A^2- ; and H_3A = 3H^+ + A^3-, where the proton ionizations may be consecutive or simultaneous. The thermodynamic values ΔG°(K), ΔH° and ΔS° were determined for the ionization of protons from the protonated compounds methionine (-NH_3^+ group only), phosphoethanalomine and phosphoserine. The compounds studied were selected because they contain one, two and three ionizable protons …

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Little Drum Mountains, An Early Tertiary Shoshonitic Volcanic Center In Millard County, Utah, Stephen H. Leedom Apr 1973

Little Drum Mountains, An Early Tertiary Shoshonitic Volcanic Center In Millard County, Utah, Stephen H. Leedom

Theses and Dissertations

The Little Drum Mountains represent a deeply eroded Eocene-Oligocene volcano, consisting of a vent complex which erupted mafic flows and flow breccias, accompanied by lahars. Flows are dominated by members of the shoshonite suite and contain up to 3.95 percent K2O, mainly occult in K-rich glass, with K2O/Na2O ratios greater than 1.0. In a few interbedded flows, apparently of the calc-alkaline series, pyroxene with varying amounts of plagioclase in a fine-grained groundmass of plagioclase, mafic minerals, and interstitial glass. An ash-flow tuff of the Oligocene Needles Range Formation unconformably overlies the volcanic sequence. Contemporaneous …

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The Determination Of Thiamin And Its Derivatives In Brain Tissue Of Control, Thiamin-Deficient, Oxythiamin- And Pyrithiamin-Treated Rats, David S. Murdock Apr 1973

The Determination Of Thiamin And Its Derivatives In Brain Tissue Of Control, Thiamin-Deficient, Oxythiamin- And Pyrithiamin-Treated Rats, David S. Murdock

Theses and Dissertations

The determination of total thiamin, free thiamin, thiamin di phosphate (TDP) plus thiamin triphosphate (TTP), and total α- hydroxyethylthiamin (HET) levels in rat brain in control, deficient, oxythiamin- (OTH) and pyrithiamin- (PTH) treated rats was accomplished. It was found that the TDP + TTP/thiamin ratio observed in the thiamin-deficient, OTH- and PTH-treated rats was constant and did not differ from the ratio observed in the control rat brains. The brain levels of TDP + TTP decreased to 39% and 12% of the control thiamin levels in deficient and PTH-treated rats respectively. The brain HET and TDP + TTP levels of …

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Transforming Ability Of Bacillus Subtilis Dna Taken Up By Barley Embryos, Christine Tolman Ence Apr 1973

Transforming Ability Of Bacillus Subtilis Dna Taken Up By Barley Embryos, Christine Tolman Ence

Theses and Dissertations

Purified Bacillus subtilis DNA taken up by one-day-old barley embryos and permanently fixed within the barley cell is shown to have maintained its biological activity in B. subtilis transformation. Cesuim chloride density gradient centrifugation of DNA isolated from the roots of barley embryos after the uptake and incorporation of radioactive, bromouracil-labelled B. subtilis DNA indicates the presence of the bacterial DNA in several discreet bands of well-defined density, whose density is changed by sonication. These preliminary findings concerning the fate of bacterial DNA taken up by barley roots are discussed in terms of the recombination model of Ledoux and Huart …

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The Purification And Characterization Of Cytochrome B₅ From Porcine Kidney, M. Dean Klingler Apr 1973

The Purification And Characterization Of Cytochrome B₅ From Porcine Kidney, M. Dean Klingler

Theses and Dissertations

A soluble form of cytochrome b_5, with a 413/280 nm ratio of nearly unity, has been isolated and purified from porcine kidney using fractional precipitation, ion exchange resins, and gel filtration procedures. The cytochrome b_5 shows heat stability up to 50° and is stable in the pH range 6.0 to 8.5. The oxidized protein exhibits an absorption maximum at 413 nm, while the reduced form shows three peaks: 423, 526, 556 nm. Molecular weight determinations have given variable results, suggesting the possibility of a polymer composed of four and eight units of a 13,500 molecular weight protomer. This study has …

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|Ni.|Pa Calorimetric Study Of The Heat Of Ionization Of Water At 10 And 40°C, And,|Nii.|Pa Calorimetric Determination Of The Heat Of Reaction Of Tris (Hydroxymethyl) Aminomethane (Tham) With Hydrochloric Acid In Aqueous Solution At 10, 25, And 40°C, Griffith Lyn Kimball Apr 1973

|Ni.|Pa Calorimetric Study Of The Heat Of Ionization Of Water At 10 And 40°C, And,|Nii.|Pa Calorimetric Determination Of The Heat Of Reaction Of Tris (Hydroxymethyl) Aminomethane (Tham) With Hydrochloric Acid In Aqueous Solution At 10, 25, And 40°C, Griffith Lyn Kimball

Theses and Dissertations

The heat of neutralization, ΔH_-N, of perchloric acid with sodium hydroxide has been determined at 10 and 40° in a low ionic strength, μ, region using a nonisothermal, constant-temperature-environment solution calorimeter. Correction of the data to infinite dilution by extrapolation of a plot of ΔH_-N vs μ^0.5 gives values at zero ionic strength for the heat of ionization of water of 14.216 and 12.695 kcal/mole, respectively, at 10 and 40° . The data are correlated with those of earlier workers to give an equation allowing the calculation of the heat of ionization of water at zero ionic strength over the …

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⁷Li(D,P)⁸Li Excitation Function :|Be[Subscript D] = 0.623 Mev To 1.968 Mev, Albert E. Schilling Apr 1973

⁷Li(D,P)⁸Li Excitation Function :|Be[Subscript D] = 0.623 Mev To 1.968 Mev, Albert E. Schilling

Theses and Dissertations

In this study the excitation function for the ^7Li(d,p)^8Li reaction is determined at incident deuteron energies ranging from 0.623MeV to 1.968MeV by counting the delayed alpha-particles as a result of the ^8Li beta decay. This excitation function reveals resonances at 0.777±0.012MeV and 1.031±0.015MeV with cross sections of 202±9mb and 188±8mb respectively. The uncertainty in the cross section values was due to three independent sources of error within this experiment, the solid angle, the ^8Li half-life, and the target (LiF) thickness. The uncertainty in the energy values was determined from an energy calibration of the accelerator used in this study. Resonances …

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Reactions Of N₂F₄ And Sf₆ With H₂ Induced By Co₂ Laser Pulses And By Electrical Discharge, John Leslie Lyman Apr 1973

Reactions Of N₂F₄ And Sf₆ With H₂ Induced By Co₂ Laser Pulses And By Electrical Discharge, John Leslie Lyman

Theses and Dissertations

A high power pulsed CO_2 laser was used to induce reactions in gas mixtures containing either N_2F_4 or SF_6. The rate of laser induced dissociation of N_2F_4 to NF_2 was as much as 1000 times faster than the thermal rate, and the rate law was of lower order than the thermal, bimolecular rate law. Explosion threshold and induction time data were obtained for butene stabilized mixtures of N_2F_4 and H_2. HF laser gain was observed during the first few microseconds of CO_2 laser pulse, but it was strongly quenched by the explosion. The laser driven reaction of SF_6 with H_2 …

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Thermodynamic Equilibrium Formation Constants And Molal Concentrations Of The Complexed Mercury-Containing Species Of Mercuric Chloride In Added Hydrochloric Acid And Methanol-Water Solvent Mixtures, Karl Jennings Walker Apr 1973

Thermodynamic Equilibrium Formation Constants And Molal Concentrations Of The Complexed Mercury-Containing Species Of Mercuric Chloride In Added Hydrochloric Acid And Methanol-Water Solvent Mixtures, Karl Jennings Walker

Theses and Dissertations

Saturated solutions of mercuric chloride in different methanol-water and hydrochloric acid solvent mixtures were equilibrated at 25.00 ± 0.01°C. Total mercury and free chloride concentrations were determined by analytical procedures and the data were analyzed with the aid of the computer. Tabulated below are the results of this study: [--see thesis for table--]

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On Improved Wkb (Uniform Asymptotic) Quantum Conditions, Dunham Corrections, The Langer Modification, And Rkr Potentials, Russell T. Pack Dec 1972

On Improved Wkb (Uniform Asymptotic) Quantum Conditions, Dunham Corrections, The Langer Modification, And Rkr Potentials, Russell T. Pack

Faculty Publications

An improvement to the WKB quantum condition for the rotation-vibration levels of diatomic molecules, known empirically to give RKR potentials of increased accuracy and to account for the Dunham correction Y00, is derived using uniform asymptotic methods. The role of the Langer transformation in this problem is also discussed.

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X-Ray Diffraction Studies On Liquids At Very High Pressures Along The Melting Curve Ii. Sodium, Keith H. Brown, J. Dean Barnett Sep 1972

X-Ray Diffraction Studies On Liquids At Very High Pressures Along The Melting Curve Ii. Sodium, Keith H. Brown, J. Dean Barnett

Faculty Publications

Coherent x-ray diffraction patterns for liquid Na have been extracted from measured patterns at 0.5, 7.5, 17, and 43 kbar along the melting curve. The experimentally determined liquid structure factor and resulting radial distribution function are given at each pressure. The position of the principal x-ray intensity peak is reproducible to within 0.5% and shows shifts of the order of 12%. The resulting nearest neighbor distance in the radial distribution function also shifts 12% but is reproducible only to approximately 2%. The distribution functions obtained at points along the melting curve suggest a simple dimensional compression or scaling; however, a …

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X-Ray Diffraction Studies On Liquids At Very High Pressures Along The Melting Curve. I. Methods And Techniques, Keith H. Brown, J. Dean Barnett Sep 1972

X-Ray Diffraction Studies On Liquids At Very High Pressures Along The Melting Curve. I. Methods And Techniques, Keith H. Brown, J. Dean Barnett

Faculty Publications

A technique using the tetrahedral anvil high-pressure x-ray system has been developed to extract coherent x-ray intensity patterns of liquids near melting from measured scattering curves in the presence of high-background counts. Radial distribution functions for liquids along the melting curve to pressures of at least 50 kbar can be obtained. At each pressure scattering curves are recorded for the liquid and solid on opposite sides of the melting curve and a subtraction is made to eliminate background and incoherent scattering. Theoretical estimates of the thermal diffuse scattering from the solid are added to the appropriately corrected difference patterns to …

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Enzymatic Synthesis Of Oligoribonucleotides Of Defined Base Sequence, Bronwyn Geraldine Hughes Jul 1972

Enzymatic Synthesis Of Oligoribonucleotides Of Defined Base Sequence, Bronwyn Geraldine Hughes

Theses and Dissertations

A possible method for the synthesis of ordered oligoribonucleotides involves primer-dependent polynucleotide phosphorylase (PNPase) synthesis using the RNase A or T1 resistant N-cyclohexyl-N'-β(4-methylmorpholinium)ethylcarbodiimide chloride (CMC-Cl) derivatives of uridine or guanosine containing primers. Thus, CMC-UpA, CMC-GpA, CMC-UpCpC, CMC-GpApC, and ApApApApU-CMC were prepared and studied as primers for PNPase in 15 min 14C-ADP polymerization reactions and also in 6-10 hr synthesis reactions. The CMC-primers were not suitable primers for PNPase catalyzed synthesis reactions for either time. The PNPases used in such studies were contaminated with nuclease that showed the following order of susceptibility: UpA > CpC, GpA > ApU, ApA. Even a highly purified …

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Β-Delayed Proton Decay Of 9c, David D. Allred, John E. Esterl, J. C. Hardy, R. G. Sextro, Joseph Cerny Jul 1972

Β-Delayed Proton Decay Of 9c, David D. Allred, John E. Esterl, J. C. Hardy, R. G. Sextro, Joseph Cerny

Faculty Publications

The delayed-proton spectrum following the β decay of 9C (t1/2=126.5±1.0 msec) was found to consist primarily of a continuum extending from 13 to 1.5 MeV, the latter being the lowest energy observed. In addition to the previously observed peaks at 9.28 and 12.30 MeV (C.M.), possible peaks between 3 and 7 MeV have been tentatively identified.

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Electrolytic Synthesis Of [Gamma]-Diketones, Leon F. Pahler May 1972

Electrolytic Synthesis Of [Gamma]-Diketones, Leon F. Pahler

Theses and Dissertations

Four γ-diketones were synthesized by using a modification of the Kolbe electrolytic condensation of β-ketocarboxylic acids. [--see equation in thesis--] The following γ-diketones were synthesized in moderate yields: 2,5-hexanedione, 4,7-decanedione, 2,2,7,7-tetramethyl- 3,6-octanedione, and 1,4-diphenyl-1,4-butanedione (34, 39, 23, and 27, respectively). However, attempted preparation of the following γ-diketones failed: 3,4-dimethyl- 2,5-hexanedione, 3,3,4,4-tetramethyl-2,5-hexanedione, and 1,4-di(2-thienyl)-1,4-butanedione. Attempts to electrolytically condense α-alkyl and α, α-dialkyl substituted monocarboxylic acids have been reported and all attempts have ended in failure; similarly, the attempts to synthesize 3,4-dimethyl and 3,3,4,4-tetramethyl- 2,5-hexanedione from 2-methyl and 2,2-dimethyl-3- oxobutanoic acid, respectively, failed. The preparation of 1,4-di(2-thienyl)-l,4-butanedione failed because the product or …

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A New Method For The Preparation Of Alkylnaphthyl Ethers And Sulfides, Edward Ying-Shih Chen May 1972

A New Method For The Preparation Of Alkylnaphthyl Ethers And Sulfides, Edward Ying-Shih Chen

Theses and Dissertations

The reaction of monohalonaphthalenes with metal alkoxides and mercaptides in a solvent mixture of the corresponding alcohol and dimethyl sulfoxide (DMSO) has been studied. These reactions are convenient methods for the preparation of alkylnaphthyl ethers and sulfides. Only direct nucleophilic substitution was observed in the reactions of bromonaphthalenes with sodium methoxide and sodium nbutyl mercaptide. The reaction of fluoronaphthalene with potassium t-butoxide also proceeded by way of direct nucleophilic substitution rather than the 1,2-dehydronaphthalene intermediate as in the reactions of bromonaphthalene with potassium t-butoxide. The use of a base which is weaker than t-butoxide can change the apparent reaction mechanism …

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Rhenium Catalyzed Hydrogenation Of Maleic Anhydride And Crotonaldehyde, William Russel Dixon May 1972

Rhenium Catalyzed Hydrogenation Of Maleic Anhydride And Crotonaldehyde, William Russel Dixon

Theses and Dissertations

The preparation of a number of supported rhenium catalysts is reported. The determination of their activity and selectivity and of optimal reaction parameters for the reduction of maleic anhydride and crotonaldehyde is reported. Optimal time of hydrogenation was chosen as one hour and pressures were chosen as 2000 psig for crotonaldehyde and 3000 psig for maleic anhydride. Quantitative reduction of maleic anhydride to tetrahydrofuran occurred at 275° with charcoal supported rhenium catalysts. Lower temperatures (ca. 200°) produce quantitative amounts of butyrolactone. Unsupported catalysts at low temperatures (100°) selectively reduce crotonaldehyde to crotyl alcohol, but at very low conversion rates. Temperatures …

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Toward Hydrogen Bonds Of Predictable Geometry, Robert Shao-Chih Hsu May 1972

Toward Hydrogen Bonds Of Predictable Geometry, Robert Shao-Chih Hsu

Theses and Dissertations

A literature review on the geometry of hydrogen bonding showed that the geometry is often de-emphasized or even ignored, probably because of the inherent flexibility of many systems studied. Examination of molecular models suggested the geometrically constrained bicyclo [2, 2, 1] heptane system wherein hydrogen bond distances and angles might be more easily predicted. Dihydroboration-oxidation of norbornadiene was shown to yield exo, exo-2,5-norbornadiol, thus clarifying uncertainties in the literature. 2, 5-Norbornadiol was oxidized to the corresponding dione, heretofore inadequately characterized. Several derivatives of the dione were prepared, and spectral data were accumulated for the dione, its precursor, and its derivatives. …

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Synthesis And Metal Coordination Properties Of Some Cyclic Polyethers And Polythioethers, Barry Lant Haymore May 1972

Synthesis And Metal Coordination Properties Of Some Cyclic Polyethers And Polythioethers, Barry Lant Haymore

Theses and Dissertations

Thermodynamic values for cation-cyclic polyether interactions for several systems are reported and discussed in light of ligand geometry, cation selectivity, solvent effects, structure, stoichiometry and the nature of the coordinate bond. Cyclic polyethers are shown to be remarkably good ligands even in water and to have marked selectivity for d0, d10 and d10 s2 cations. Syntheses of one new cyclic polyether and several new mixed cyclic polyether-thioethers are reported. Cyclic chelates with smaller rings are shown to prefer smaller cations, but this selectivity is masked by the hydration energy of the cation. Except for thiophillic cations such as Hg2+ and …

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Enzymatic Synthesis Of Oligoribonucleotides Of Defined Base Sequence, Mark J. Rowe May 1972

Enzymatic Synthesis Of Oligoribonucleotides Of Defined Base Sequence, Mark J. Rowe

Theses and Dissertations

The synthetic reaction of ribonuclease T_1 has been studied as to its potential for the synthesis of oligoribonucleotides of defined base sequence. Conditions have been determined for maximum synthesis with respect to percentage incorporation of both guanosine 2',3'-cyclic phosphate (donor), and cytidine (acceptor). With regard to maximum acceptor incorporation, a donor blocked at the 5'-hydroxyl has been used to drive the reaction. It has also been shown that acceptor incorporation decreases as the chain-length increases up to the hexanucleotide. Synthesis of a 3'-blocked substrate for polynucleotide phosphorylase for use in chain termination studies was attempted using adenylate kinase. In this …

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On The Mechanism Of Low-Temperature Termolecular Atomic Recombination, Russell T. Pack, Richard L. Snow, Wesley D. Smith Jan 1972

On The Mechanism Of Low-Temperature Termolecular Atomic Recombination, Russell T. Pack, Richard L. Snow, Wesley D. Smith

Faculty Publications

A simple theory of gas-phase termolecular atomic recombination kinetics is presented which treats the bound-complex (BC) mechanism in a fashion which parallels the Roberts, Bernstein, and Curtiss resonance theory of the energy-transfer (ET) mechanism. The ET rate constant has a low temperature maximum, but the BC rate constant does not. The contributions of the two mechanisms to the low-temperature recombination of hydrogen atoms, with He, Ar, and H2 as third bodies, are estimated and compared. The presence (absence) of a low-temperature maximum in the observable total rate constant is determined by absence (presence) of bound vibrational levels of the hydrogen-third …

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