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Degree Discipline:
Chemistry
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UNT Theses and Dissertations
A Chemical Analysis of the Blackeyed Pea
Date: 1941
Creator: Davis, Stanley F.
Description: The purpose of this research problem is to determine the chemical composition of the blackeyed pea and to make a comparative study of the results. The value of the blackeyed pea as food, its chemical nature, and possible industrial uses are studied and recorded.
Contributing Partner: UNT Libraries
Permallink:digital.library.unt.edu/ark:/67531/metadc70288/
Thermodynamics of Mobile Order Theory: Solubility and Partition Aspects
Date: August 2004
Creator: De Fina, Karina M.
Description: The purpose of this thesis is to analyze the thermochemical properties of solutes in nonelectrolyte pure solvents and to develop mathematical expressions with the ability to describe and predict solution behavior using mobile order theory. Solubilities of pesticides (monuron, diuron, and hexachlorobenzene), polycyclic aromatic hydrocarbons (biphenyl, acenaphthene, and phenanthrene), and the organometallic ferrocene were studied in a wide array of solvents. Mobile order theory predictive equations were derived and percent average absolute deviations between experimental and calculated mole fraction solubilities for each solute were as follows: monuron in 21 non-alcoholic solvents (48.4%), diuron in 28 non-alcoholic solvents (60.1%), hexachlorobenzene (210%), biphenyl (13.0%), acenaphthene (37.8%), phenanthrene (41.3%), and ferrocene (107.8%). Solute descriptors using the Abraham solvation model were also calculated for monuron and diuron. Coefficients in the general solvation equation were known for all the solvents and solute descriptors calculated using multilinear regression techniques.
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Permallink:digital.library.unt.edu/ark:/67531/metadc4626/
Computational studies of bonding and phosphorescent properties of group 12 oligomers and extended excimers.
Date: August 2008
Creator: Determan, John J.
Description: Density functional (ca, BLYP, BPW91, B3LYP and B3PW91), MP2 and CCSD(T) methods in combination with LANL2DZ or cc-pVxZ-PP (where x=D(double), T(triple) Q(quadruple), and 5(quintuple)) basis sets have been employed in computing electronic transition energies of zinc and cadmium monomers. CCSD(T)/aug-cc-pV5Z-PP combination finds values that are 150 cm-1 from the experimental value for the zinc monomer and 240 cm-1 remove from the cadmium monomer excitation experimental value. These method/basis set combinations are also used to find spectroscopic values (re, De, we, wexe, Be , and Te) that rival experimental values for dimers and excimers. Examples of this can be seen with the CCSD(T)/aug-cc-pV5Z-PP combination phosphorescent emission results. The values found are within 120 cm-1 of the zinc emission energy and 290 cm-1 of the cadmium emission energy. While this combination rigorously models spectroscopic constants for monomers, dimers, and excimers, it does not efficiently model these constants for larger clusters with available modern computational resources. It is important to show spectroscopic trends (bonding, phosphorescent excitation and emissions) as clusters increase as the monomer and dimer emission energies do not model solid state metallophilic interactions and phosphorescence. The MP2/LANL2DZ combinations show qualitative cooperative bonding trends in group oligomers and extended excimers as size ...
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Permallink:digital.library.unt.edu/ark:/67531/metadc9108/
Hydantoins as Anticonvulsants. VIII. 5-Alkylmercapto Derivatives of 3-Methyl-5-Phenylhydantoin
Date: January 1954
Creator: Dick, Clarence Reinhardt
Description: Recent years have seen a rapid increase in the search for new compounds to be employed in the treatment of convulsions associated with epilepsy and related ailments. The properties desired are a higher degree of effectiveness and lower toxicity than those already in use. This thesis describes the effect of methylation of the 5-alkylmercapto-5-phenylhydantoins.
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Permallink:digital.library.unt.edu/ark:/67531/metadc130353/
The Mercury Photosensitized Reactions of some Hydrocarbons
Date: 1946
Creator: Dickinson, Ermintrude
Description: The problem was to study the behavior of several hydrocarbons when they were subjected to ultraviolet light of 2536 Å in the presence of mercury vapor.
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Permallink:digital.library.unt.edu/ark:/67531/metadc53810/
Mechanisms of Methoxide Ion Substitution and Acid- Catalyzed Z/E Isomerization of N-Methoxyimines
Access: Use of this item is restricted to the UNT Community.
Date: December 2001
Creator: Dolliver, Debra D.
Description: The second order rate constants for nucleophilic substitution by methoxide of (Z)- and (E)-O-methylbenzohydroximoyl fluorides [C6H4C(F)=NOCH3] with various substituents on the phenyl ring [p-OCH3 (1h, 2h), p-CH3 (1g, 2g), p-Cl (1f, 2f), p-H (1e, 2e), (3,5)-bis-CF3 (1i, 2i)] in 90:10 DMSO:MeOH have been measured. A Hammett plot of these rate constants vs σ values gave positive ρ values of 2.95 (Z isomer) and 3.29 (E isomer). Comparison of these rates with methoxide substitution rates for Omethylbenzohydroximoyl bromide [C6H4C(Br)=NOCH3] and Omethylbenzohydroximoyl chloride [C6H4C(Cl)=NOCH3] reveal an element effect for the Z isomers of Br:Cl:F(1e) = 2.21:1.00:79.7 and for the E isomers of Cl:F(2e) = 1.00:18.3. With the p-OCH3-imidoyl halides the following element effects are found: Br:Cl:F(1h) = 2.78:1.00:73.1 for the Z isomer and Br:Cl:F(2h) = 1.97:1.00:12.1 for the E isomer. Measurement of activation parameters revealed ∆S≠ = -17 eu for 1e and ∆S≠ = -9.9 eu for 2e. Ab initio calculations (HF/6-31+G*, MP2/6-31+G*//HF/6-31+G*, B3LYP/6- 31+G*//HF/6-31+G*, HF-SCIPCM/6-31+G*//HF/6-31+G*) were performed to define the reaction surface. These calculations demonstrate a relatively large barrier for nucleophilic attack in relation to halogen loss and support the experimental findings that this reaction proceeds by an addition-elimination mechanism (AN# + DN). The imidoyl fluorides have been used to synthesize ...
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Permallink:digital.library.unt.edu/ark:/67531/metadc3017/
Infrared Studies of Anions of Organic Acids
Date: August 1962
Creator: Dyke, Maurice Arthur
Description: The present work is a part of a systematic investigation of the frequency shifts in infrared absorption produced by changing to the anions carbonyl containing acidic compounds.
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Permallink:digital.library.unt.edu/ark:/67531/metadc108151/
A Chemical, Physical, and Biological Investigation of the Total Suspended and Dissolved Substances in Lake Dallas with Emphasis on Sanitation
Date: 1942
Creator: Eads, Ewin A.
Description: The purpose of this investigation is to determine the suspended organic matter and the total phosphorus in the waters of Lake Dallas and to evaluate these findings. Since organic matter floating in lakes is largely composed of minute plants, animals, and detritus derived from animals and plants, the fertilizing effect of phosphorus must be considered as an integral part of this problem.
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Permallink:digital.library.unt.edu/ark:/67531/metadc75354/
General Chemistry Topic Coverage (GCTC) comparison between community colleges and universities in the United States.
Date: December 2006
Creator: El-Ashmawy, Amina Khalifa
Description: This study is based on survey responses of 224 general chemistry instructors at United States (U.S.) community colleges and universities representing 46 states. The mean values of General Chemistry Topic Coverage (GCTC) score, developed by this researcher specifically for this dissertation study as a measure of course content, were statistically analyzed. The aim of this study is to answer five research questions: (a) Is there a difference in mean GCTC scores between U.S. community colleges and four-year colleges and universities? (b) If there is a difference in mean GCTC score between the two study groups, what are the observed differences in subtopics covered between community colleges and four-year colleges and universities? (c) Considering both community colleges and universities, is there a difference in mean GCTC score between the different designated U.S. regions? (d) Considering both community college and university professors, is there a difference in GCTC score for professors with a master's degree compared to those with a doctorate?, and (e) Is there a correlation between GCTC score and the percentage of students that major in science? Results indicate that there is a statistically significant difference in course content between community colleges and universities, there is a statistically significant difference ...
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Permallink:digital.library.unt.edu/ark:/67531/metadc5464/
Pyridinium and Pyrazinium Derivatives of 2,3-Dichloro-1,4-Naphthoquinone
Date: 1956
Creator: El-Eris, Talib Mihsin
Description: This investigation deals with the synthesis of 2-alkylpyridine and 2-alkylpyrazine derivatives of 2,3-dichloro-1,4-naphthoquinone. These compounds will be tested for physiological activity by Parke-Davis and Company.
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Permallink:digital.library.unt.edu/ark:/67531/metadc107879/