Physical Sciences and Mathematics Commons^™

Examination Of The Acid Etching Process Used In Preventative Dentistry, Robert Charles Morgan

Honors Theses

Nuva-Seal is a bisphenol-A-glycidyl-methacrylate monomer which in its polymerized form seals a tooth to prevent carie formation. Prior to application the tooth surface is pretreated with an etching solution to increase the bond strength. The etchant solution is 50% by weight H3PO4 and 7% by weight Zn0. Previous investigations preformed at Union College have determined qualitatively that a substantial portion of enamel is removed by the acid pretreatment. In addition, an extensive literature search into the development of the etching process was performed in order to validate or repute its usefulness.

A Study On Gaseous Ebullitions Of De Gray Reservoir, Arkansas, David Pinkston

Honors Theses

This study was undertaken in order to determine the nature of and the factors that influence the gaseous ebullitions of De Gray Reservoir near Arkadelphia, Arkansas during a yearly cycle.

Two major types of gaseous ebullition are described in the literature. The first has to do with the production and ebullition of elemental oxygen from photosynthesis (Porcella et al., 1975). Hutchinson (1957) predicts that the formation of oxygen bubbles in this manner is limited to very shallow, well lighted, warm waters.

The second type of gaseous ebullition involves the anaerobic digestion of organic matter (Reeburgh, 1969). Anaerobic conditions exist in …

A Study Of The Acid Etch Pretreatment Used With The Nuva-Seal" Dental Process, Judith Ann Komoroski

Honors Theses

Nuva-Seal, a bisphenol-A-glycidyl-methacrylate polymer, is applied to the occlusal surface of teeth to prevent tooth decay. Before application of the sealant, the enamel surface is etched for one minute by a 50 percent by weight solution of phosphoric acid containing seven percent by weight of zinc oxide. This treatment renders the tooth surface more porous and surface active to insure a strong bond between tooth and sealant. Past studies at Union College have shown that the etching treatment removes much of the enamel from the tooth. In the current work the amount of tooth removed by acid etching was determined …

The Decomposition Of Azibenzil In The Presence Of Oxygen, Nancy C. Westby

Honors Theses

The ozonolysis of acetylenes is thought to proceed through the formation of ∝-carbonyl carbonyl oxide intermediates. This reaction has been shown to parallel the effect of molecular oxygen on ketocarbenes. Azibenzil, a diazo-ketone, will decompose to a ketocarbene by the action of heat, light or catalyst. The ketocarbene may decompose by two pathways: Wolff rearrangement and non-rearrangement. The Wolff rearrangement route will produce methyldiphenylacetate (upon addition of methanol), benzophenone, tetraphenylglycolide and possibly other high molecular weight polymeric species. The non-rearrangement pathway will presumably produce ∝-carbonyl carbonyl oxides which will decompose under varying circumstances to produce benzyl, benzoic anhydride, benzophenone, tetraphenylglycolide …

The Addition Of Singlet Oxygen To N, N-Diethyl-1-Propynylamine, Kenneth S. Zimmerman

Honors Theses

The addition of singlet oxygen to N, N-diethyl-1-pro-pynylamine produced 60-75% yields of N, N-diethyl pyruvamide and various carbon dioxide contamination products under several conditions. Products under several conditions. Product formation was independent of solvent and photosensitizer and was shown to proceed via a singlet oxygen addition mechanism with no free radical involvement. The water addition product was also demonstrated to be N, N-diethyl propanamide. A dioxetene intermediate is suggested as the precursor of N, N-diethyl pyruvamide.

The Preparation And Kinetics Of A Sterically Hindered Gold (Iii) Complex, Michael R. Golden

Honors Theses

The alkyl substituted gold (III) complex [Au(1, 4, 7-Me3dien)Cl] (PF6)2 [where 1, 4, 7-Me3dien respresents (CH3) HNCH2CH2N(CH3)CH2CH2NH(CH3)] has been synthesized. The cation of this compound differs from previously synthesized gold (III) complexes of similar structure since it can form a conjugate base only by loss of hydrogen from a terminal nitrogen. Aqueous solution chemistry studies of this ion reveals that the Cl- is hydrolyzed before loss of a proton from the ligand which is the reverse of the sequence observed with previously studied ions. Monobromo substitution rates are found to be slower than for the complex with no alkyl substitution …

Reactions Of Diazoketones With Neighboring Carbon-To-Carbon Double Bonds, Robert James Perry

Honors Theses

It was hoped that the carbon-carbon double bond in an unsaturated diazoketone would act as a nucleophile in an intramolecular attack to give a ring closure. Experimental results indicate that the double bond did participate, but in such a manner so as to give only substituted products, rather than cyclic ones. We suggest a diazonium salt intermediate in the initial formation of these substituted products. Polymerization and oxonium formation after reactopm with a Lewis acid solvent account for the polymers formed and some of the substituted products.

Co2 Laser Induced Decomposition Of Freon 113, Richard S. Herrick

Honors Theses

Irradiations were made on CCl2FCClF2, Freon 113, to see if the resulting decomposition was photochemical in nature. The irradiation source was Molectron 250, continuous wave, infrared laser operating in the single line mode. The wavelength of irradiation was varied over the range 9.473 µ to 9.734 µ. The pressure except one (in which the cell window broke). Relative rates of reaction were calculated for a constant power absorbed by the sample of 7.8 ± 4W. These relative rates were plotted against the irradiation wavelength. This was superimposed on a plot of the IR band for Freon 113 which was irradiated …

Determination Of The Rate Of Formation Of Hcn, Mitchell Hull

Honors Theses

Nitric oxide is a major air pollutant arising from fossil fuel combustion, yet the fuel contribution to its formulation is uncertain. Since, in combustion, fossil fuels undergo disintegration before oxidation takes place, the study of the pyrolsis of a model constituent of fossil fuels can shed light on NO formation. The rate of inert pyrolytic disappearance of pyridine and the rate of formation of the principal Nitrogen-containing pyrolytic product, HCN, was studied in an inert atmosphere. The rate constant for the formation of HCN and its temperature dependence were determined.

The Effect Of Solvent Polarity On The S1-T2 Energy Gap In 9- And 2-Substituted Anthracene Derivatives In Aromatic And Non-Aromatic Solvents, John S. Facci

Honors Theses

Fluorescence quantum yields, fluorescence lifetimes, energies and intersystem crossing activation energies were measured for methyl-2-anthroate and methyl-9-anthroate in various polar, non-polar and aromatic solvents.

The Decomposition Of Phenyl-Benzoyl-Diazamethane And Its Relevance To Alkyne Ozonolysis, Joy A . Sawyer

Honors Theses

The thermal or photolytic decomposition of diazo compounds is known to produce a carbonyloxide in the presence of oxygen. Analogously, ∝-diazoketones should produce acyl carbonyloxides. This intermediate is identical to one proposed for the ozonolysis of alkynes and its substantiation is the purpose of this study. By examining the products of the thermal, copper catalyzed phenylbenzoyldiazomethane decomposition, one should be able to determine the intermediate’s presence. Benzoic anhydride, benzil and methyl diphenyl-acetate have been identified as products and tetraphenylglycolide is also thought to be present. Methyl diphenyl-acetate is the result of Wolff rearrangement, while the other three are proposed to …

Mechanisms Of Saponification Of Sterically Hindered Esters By Optical Activity And Kinetic Studies, George A. Walrath

Honors Theses

This thesis presents methods for preparation of sterically hindered organic acid esters. The secondary- and tertiary-butyl esters of 2,2’ dimethylpropanoic acid (pivalic acid, neo-pentanoic acid, or trimethyacetic acid) were prepared by suggested methods. The best method proved to be that suggested by Bochkova, Proskuryakov, Pirozhkoc and Eidus, where the esters of neo-acids are prepared through their respective acid chlorides. In the case studies in this thesis, the acid chloride of neopentanoic acid (pivaloyl chloride) was reacted with secondary or tertiary-butyl alcohol. Kinetic studies of the saponification of secondary-butyl pivaloate were made at various temperatures, and from the data obtained, the …

The Study Of Gas Decomposition Due To Laser Stimulation, James A. Burke

Honors Theses

A survey of various gases known to emit radiation when pumped with a laser was undertaken to discover whether or no these gases would decompose as a result of the laser stimulation. A literature search provided some previous work in this area but left many gases unstudied. Methanol, 1,1-difluoroethylene, ethanol, methylene chloride and methyl iodide were subjected to laser irradiation, Using an infrared spectrophotometer as a detector, none of these five gases showed clear evidence of decomposition, Because of inherent limitations of the IR detection system, a mass spectrometer was put into operation. Calibration of this instrument was performed, Results …

Synthetic Approaches To Specifically Labeled Dimethyl-Dideuterionaphthalenes, Armand J. Scatena

Honors Theses

The purpose of this work was the study of synthetic approaches to specifically labeled deuterated 1, 4-dimethylnaphthalenes. Alkylation of ortho- and para-dibromobenzenes eventually led to the formation of some 1, 4-dimethylnaphthalene although deuteration was rather poor. Under the conditions employed, much isomerization of Friedel-Crafts products resulted. Not only did the bromines rearrange intramolecularly, but substantial rearrangement of the alkylating moiety may also have occurred. The major products of these reactions were dibromophenylcyclohexanes. It appears from the products obtained by the methods employed in our work that specific monodeuteration rather than specific dideuteration should be used to attain the desired product.

The Carbon Dioxide Laser Induced Decomposition Of Freon 113, Curtland Chester Brown Iii

Honors Theses

The carbon dioxide laser irradiation of Freon 113, 1,1,2 trichlorotrifluoroethane, yielded Freons 11, trichloro­fluoromethane, l2, dichlorodifluoromethane, and 13, chloro­trifluoromethane, along with chlorotrifluoroethylene and unidentified products. Product formation was found to increase as the pressure of the starting material and laser power were increased, although no formal pressure or power dependenry could be determined. The Freon products were identified using a gas chromatograph in the flame ionization mode with a molecular sieve column. Chlorotrifluoroethylene was identified with an infrared spectrophotometer. The buildup of unidentifiPd brown tars was observed on the glass walls of irradiated cells. The pyroysis of Freon 113 has …

Hydrothermal Growth Of Quartz, Samuel J. Casella

Honors Theses

The hydrothermal method of crystal growth utilizes a solvent at high temperature and under high pressure to grow large single crystals. A suitable aparatus was constructed for research ith this unique method.

The Design, Development And Construction Of A Low Cost Multi-Purpose Computer/Interface System For On-Line Experimentation: Applications To Time Averaging Of Nmr Spectra And Other Chemical Instrumentation Problems, Steven A. Carr

Honors Theses

The project goal was the development of a low cost multipurpose microprocessor interfacing system that would be adaptable to a number of commonly encountered chemical instruments (such as NRM, GC, IR, and UV-VIS.) for the purpose of control, data acquisition processing. The Altair Microprocessor with 4K random access memory was constructed from kit form; it functions as the computer portion of the system. The digital to analog and analog to digital signal conversion elements as well as timing, control and other necessary logic functions are incorporated in the electronic interface portion of the system. The computer, interface, principles of time …

The Synthesis And Decomposition Of O-Substituted Phenylhydroxylamines, Helen Carol Kennicott

Honors Theses

0-(phenyl)hydroxylamine and its p-nitrated derivative were synthesized for use in a study of substitution reactions at an sp3 hybridized nitrogen atom. The 0-(phenyl)hydroxylamine was decomposed thermally in several nonnucleophilic solvents and in water, with base present. It is proposed that in organic solvents, the decomposition proceeds by a radical mechanism involving a solvent cage intermediate. Ammonia and aminophenols are the major products. In water, it appears that an SN1 reaction producing phenoxide may compete with the radical mechanism.

The Synthesis Of 2, 11-Dithiabenzo - [3.3] - Paracyclophane And An Octadeutero Derivative, Paul M. Begley

Honors Theses

The purpose of this work was the synthesis of 2, 11 -dithia-benzo- [3.3] -paracyclophane and its octadeutero derivative 2,11-dithia- 3,3, 5, 6, 8, 9, 10, 10-octa­deutero-benzo - [3.3] paracyclophane. A comparison of their nuclear magnetic resonance spectra as well as their mass spectra will unequivocably provide proof of their successful synthesis.

Ozone Complexes With Substituted Aromatic Compounds, David C. Eaton

Honors Theses

Ozone has been observed to complex with aromatic compounds at low temperatures. The ability of an aromatic system to complex with ozone appears to be due to the inductive effect of the substituent on the pi system. The experimental work was done in the solid phase at temperatures of -175° C to -186° C. Under these conditions all the substituted aromatics with electron withdrawing groups did not complex including benzene. The complexes are highly colored. To insure the reversibility of the pi complex, infrared spectra were taken of some of the aromatic species before and after complexing.

A Facile One Step Synthesis Of Some New 2-Hydroxy-4,6-Bis Aryl S-Triazines And Related Compounds, Howard Steven Grossberg

Honors Theses

In the past few years the symmetrical triazines have developed extreme importance in biochemical research as well as importance in industrial applications. In our research we have developed a facile, one-step synthesis of a number of 2-hydroxy-4, 6-bis aryl symmetrical triazines based upon the addition of the anion of urea and an aromatic nitrile, with the aryl group including a number of halogenated benzenes, pyridine, or benzene itself. The structure of these compounds had been proved by microanalysis and by both infra-red and mass spectroscopy. The further versatility of the synthesis has also been explored, and by replacing the urea …

The Preparation And Kinetic Studies Of Two Sterically Hindered Gold (Iii) Complexes, James Forrest Stevens

Honors Theses

Previous studies indicate substitution of bromide ion for chloride ion in [Au(Et4dien~H)c.i] +occurs at a rate almost independent of the bromide ion concentration, while similar reactions with [Au(dien-H)Cl]+, [Au(Me2dien-H)c!]+ and [Au(Me4dien-H)c~+ show rates dependent on bromide ion concentration as usually encountered for square planar complexes. There is retardation of the reaction by steric and electronic effects with increased N-alkyl substitution of the triamine. It has also been postulated that substitution of [Au(Et2dien-H)cJ]+ proceeds via a ring-opening mechanism. The purpose of this research was to study further the effect of steric hindrance on rates of substitution of two additional gold(III) complexes. …

Effect Of Solvent Polarity On The Singlet-Triplet Energy Gap Of Methyl-2-Anthroate, William Gregg Hawkins

Honors Theses

Nonradiative processes cause the fluorescence quantum yield to be less than one. Elucidation of nonradiative decay mechanisms without knowing the location of triplet states is difficult. Determination of the fluorescence quantum yield (Øf) as a function of temperature can provide valuable information about relative location of triplet states and the nonradiative processes which result from having a triplet near the energy of the first excited singlet state. Methyl-2-anthroate is very sensitive to solvent polarity. The Øf values and S1 energies vary greatly, depending on the solvent environment. Temperature studies on Øf have indicated the intersystem crossing (ISC) to a nearby …

Synthesis Of 2,4-Dichloro-6-Methylborazine And 2-Chloro-4,6-Dimethylborazine, Deborah Ann Scribner

Honors Theses

In the attempted preparation of 2, 4, 6-trimethylborazine, two unknown products were isolated. It was suspected that these could be 2-chloro-4, 6-dimethylborazine and 2, 4-dichloro-6-methylborazine. Due to the difficulty of separation of the two products, they were not positively identified. These two compounds were then chosen for synthesis and characterization since they would be useful starting materials for the preparation of unsymmetrically substituted borazines and since there is little data on unsymmetrical borazine derivatives. It was later decided that the 2, 4-dichloro-6-methyl-borazine would be synthesized first since it would be earlier to control the mole ratio of reactants to favor …

Dielectric Constants And Pair Interactions In Polar Molecules, Guy Nicholas Pultz

Honors Theses

Intermolecular interactions effect the physical properties of polar substances to varying degrees. One property for which there exists the possibility of separating out the various components of this interaction (pairs, triplets, etc.) is the total molar polarization of a substance. These effects are quite dependent upon temperature and pressure, so if one is going to make measurements over a large range of these variables, one must develop a system that is capable of handling the conditions. Along with this there must be the necessary instrumentation and other apparatus for measuring dielectric constants which define total molar polarization. In this thesis, …

The Synthesis Of Primary O-Substituted Hydroxylamines For The Study Of Nucleophilic Substitution At The Electrophilic Nitrogen Center, Richard Martin Sommer

Honors Theses

Within the past fifteen years bimolecular nucleophilic substitution reactions at the sp3 hybridized nitrogen center have been the topic of some investigation. The synthesis of 0-substituted hydroxylamines was undertaken in order to obtain substrates for the study of these substitution reactions. Mesitylenesulfonyl chloride and t-butyl N-hydroxycarbamate were reacted to form the N-blocked t-butyl N-mesitylenesulfonyloxycarbamate. Subsequent acid cleavage of the nitrogen blocking group with trifluoroacetic acid yielded 0-mesitylenesulfonylhydroxylamine. Unsuccessful kinetic studies of the reaction of iodide with 0-mesitylenesulfonylhydroxylamine are reported. Attempts to synthesize 0-(2, 4-dinitrophenyl) hydroxylamine utilizing t-butyl N-hydroxycarbamate and ethyl acetohydroxamate as a sources of N-blocked hydroxylamine failed. In both …

Determination Of The Lead Content Of Paint Chips Using The Lead Selective Electrode, Edward Jordan Morgan

Honors Theses

This study was undertaken to examine the feasibility of using the lead selective electrode to determine the lead content of paint chips. There is a need today, for a fast, inexpensive method for screening large numbers of paint chip samples. Chips containing hazardous levels of lead, e.g., 10% by weight, should be identified, so that steps may be taken to make them inaccessible to children. A laboratory report is frequently required, in order to justify the costly job of complete removal of the paint or covering with paneling. The lead selective electrode, which operates in a manner similar to that …

Stereoselectivity In Bis-1 (2-Pyridyl) Ethylaminecobalt (Iii), Richard Lindsay Wellman

Honors Theses

Recently Michelsen reported the synthesis of a new series of bis-chelated cobalt (III) compounds using 2-pyridylmethylamine (pm) as a bidentate ligand.4 Replacement of a methylene hydrogen of pm with a methyl group gives the optically active compound 1-(2-pyridyl) ethylamine (pa). Model studies show that when bound to a cobalt molecule, the ligand methyl group can assume either and axial or an equatorial position. On the basis of predictions by Corey and Bailar1 using the ligand 1, 2-diaminopropane, it was thought stereoselectively might be observed in the reaction of pa with cobalt. To determine if this was so Michelsen’s reactions were …

Base Strength And Concentration Effects On Orientation In Elimination Reactions, Frederick Norman Preuninger

Honors Theses

The orientation of base promoted eliminations depends on several factors including base strength and size. Neither of these factors account for all of the observed results. A new factor, ion pairing of the base, is suggested. Results of elimination reactions using sodium benzoate derivatives are found to be consistent with this explanation. Kinetic data for an ion pair mechanism were sought but not obtained.

Relative Rate Of Ozonolysis Between Symmetrical And Unsymmetrical Olefins, Wai Lum Yuen

Honors Theses

There are two theories about the mechanism of the ozone-olefin reaction. One is that ozone makes a one-step four-center attack on the olefin to form a primary ozonide. Another theory is that ozone makes an electrophilic attack of the olefin to form a pi complex. The pi complex then collapses into the primary ozonide. The relative rates of reaction of a series of symmetrical and unsymmetrical olefins were determined. Gas chromatograph was used to measure the relative concentration of the various olefins before and after ozonolysis. The relative rates of ozonolysis were then calculated from the data. It was observed …