Chemistry Commons^™

Electrooxidation Of Linear Alkyl Benzene Sulfonate (Las) On Pt Electrodes, Bi̇rgül Yazici, Si̇bel Zor

Turkish Journal of Chemistry

The electrochemical behaviour of linear alklybenzene sulfonate (LAS) on Pt electrodes was investigated in 0.05M Na_2SO_4 and in 0.1M NaCl at pH=8 by the potentiokinetic method and by electrolysis. The anodic and cathodic semilogarithmic current-potential curves were obtained between -1.6V - +1.6V. The experimental discharge potentials were determined by means of current-potential-curves obtained by electrolysis between 0-3V. The percentages of surface active material remaining in the solution after specified periods (0-6hrs) were determined for different initial concentrations of LAS (30, 150, 300 ppm) by using a potentiostat at +1.6V and by applying a potential of 20V via a direct current …

Nepetalactones And Other Constituents Of Nepeta Nuda Ssp. Albiflora, Gamze Kökdi̇l, Sabi̇ha M. Yalçin, Gülaçti Topçu

Turkish Journal of Chemistry

The hexane extract of Nepeta nuda ssp. albiflora led to the isolation of six known monoterpene nepetalactones, 4a\alpha,7\alpha,7a\alpha-nepetalactone (1), 4a\alpha,7\alpha,7a\beta-nepetalactone (2), 4a\beta,7\alpha,7a\beta-nepetalactone (3), 4a\beta,7\alpha,7a\alpha-nepetalactone (4), 4a\alpha,7\beta,7a\beta-nepetalactone (5), 3\alpha-hydroxy-4a\alpha,7\alpha,7a\alpha-dihydron\-epe\-tal\-actone (=nepetalic acid) (6) and a dimeric 5,9-dehydronepetalactone (7) along with two known steroids \beta-sitosterol and sitosterol 3-one and a triterpene betulinic acid. The acetone extract of the same plant afforded compound 7 in a higher yield in addition to compounds 2 and 6, and sesquiterpene caryophyllene oxide, the iridoid glucoside 1,5,9-epideoxyloganic acid, the triterpenoids oleanolic, ursolic and betulinic acids, and sitosterol 3\beta-glucoside.

An Investigation Of The Formation Mechanism Of Allene Or Alkyne In The 6,7-Benzobicyclo[3.2.1]Octane System By Deuterium Labeling Experiments, Yavuz Taşkesenligil, Ferhan Tümer, Cavi̇t Kazaz, Meti̇n Balci

Turkish Journal of Chemistry

In order to reveal the real intermediate in the base-promoted reaction of 1, 3-bromo-4,4-dideuterio-6,7-benzobicyclo[3.2.1]octa-2,6-diene 10 was synthesized and its HBr elimination reaction studied. Reaction of 10 with potassium tert-butoxide yielded butoxyl ether 18 in which proton-deuterium exchange has occured.

Reaction Of Tribromonitromethane With Aldehydes And Ketones In The Presence Of Zn Metal In Aqueous Medium, Ali̇ Shaker Mahasneh

Turkish Journal of Chemistry

Aldehydes and ketones react with tribromonitromethane in the presence of zinc metal dust, ammonium chloride and water to give dibromonitroalcohols in good yields.

A Study Of The Thermodynamic Properties Of Poly [2-(3-Mesityl-3-Methylcyclobutyl)-2-Hydroxyethyl Methacrylate] At Infinite Dilution Using Inverse Gas Chromatography-2-Hydroxyethyl, İsmet Kaya, Kadi̇r Demi̇relli̇

Turkish Journal of Chemistry

Some thermodynamic quantities were obtained for the interactions of poly [2-(3-mesityl-3-methylcyclobutyl)-2-hydroxyethyl methacrylate] with alcohols, ketones, acetates, aromatics and alkanes by inverse gas chromatography in the temperature range 160-200°C. The specific retention volumes, V°_g, weight fraction activity coefficients of solute probes at infinite dilution, \Omega^{\infty}_1, Flory-Huggins thermodynamic interaction parameters, \chi^{\infty}_{12} between polymer and solvents were determined. The partial molar free energy, \Delta \bar{G}^{\infty}_{1}, the partial molar heat of mixing, \Delta\bar{H}^{\infty}_1 at infinite dilution and the solubility parameters of the polymer, \delta_2 were calculated.

Electrochemical Reduction Of Methyl Cinnamate In The Presence Of 1,3-Bis(4-Methyl Phenylsulphonyloxy)Propane, Mustafa Güllü

Turkish Journal of Chemistry

Electrochemical reduction of methyl cinnamate in the presence of a dielectrophile, such as 1,3-bis(4-methyl phenylsulphonyloxy)propane gives two major products: trans- (\pm) methyl 2-phenylcyclopentanecarboxylate and trans- (\pm) methyl 2,3-diphenyl-5-oxo-cyclopentanecarboxylate. The ratio of products basically depends on the electrolysis conditions.

Electrochemical Characterization Of Al_2 O_3 -Ni Thin Film Selective Surface On Aluminium, Fi̇gen Kadirgan, Ewa Wackelgard, Mete Söhmen

Turkish Journal of Chemistry

Solar thermal collectors represent a widely used type of system for the conversion of solar energy. In order to produce selective coatings on aluminium substrates to be used as absorber plates in high efficiency solar collectors, nickel pigmentation was applied to anodically oxidised surfaces. Electrochemical dc methods are used to study the oxidation of aluminium as functions of the following electrolysis conditions: applied current, pH, temperature and concentration of electrolyte. The properties of the oxidised aluminium surfaces are investigated by cyclic voltammetry. Nickel pigmentation of porous aluminium surfaces was also performed as a function of electrochemical pigmentation conditions by ac …

The Development And Validation Of A Methodology For The Analysis Of Polyaromatic Hydrocarbons In Air Particulates (Indoor And Outdoor), Kathryn O'Malley

Masters

PAH form a large class of ubiquitous pollutants mainly of anthropogenic origin. Several PAH found in air particulates have been identified as carcinogens and mutagens. Sixteen of these PAH have been listed by the USEPA as priority pollutants. This research is concerned with the development and optimisation of a method for the analysis of these sixteen PAH in air particulates. Soxhlet and ultrasonic extraction procedures were investigated to optimise the recoveries from spiked glass fibre filters with a standard 1ppm mixture of the 16PAH. Standard mixtures of the 16 PAH were analysed by HPLC with fluorescence detection with approx. linearity …

Characterisation And Optimisation Of Gypsum Crystallization, Catherine H. Shannon

Theses

Gypsum is produced as a by-product during the citric acid production process at ADM Ringaskiddy. The particle size and filterability of the gypsum has a critical bearing on the overall citric acid production rate. Prior to August 1996, research in the area of gypsum crystal optimisation at ADM had concentrated on the application of vortex mixing to perform the gypsum formation reaction. While the gypsum crystals produced with vortex mixing were found to be desirably clear of microcrystalline gypsum, the crystals were considerably smaller and more difficult to filter and wash. This research project sought to retain the advantages conferred …

New Polyether Toxins From Shellfish And Marine Phytoplankton: Isolation Studies And Development Of Analytical Methods, Alan G. Bishop

Theses

There are three classes of polyether toxins responsible for Diarrhetic Shellfish Poisoning (DSP) world-wide. The causative toxins are okadaic acid (OA) and derivatives (DTXs), pectenotoxins (PTXs) and yessotoxins (YTXs). The origin of these toxins are phytoplankton from Dinophysis or Prorocentrum spp. OA has been demonstrated for most outbreaks in Europe and more recently a new isomer DTX-2 has been reported in Ireland.

Marine phytoplankton biomass samples consisting predominantly of Dinophysis acuta, were acquired using a large double plankton net from waters off the South-west coast of Ireland. Analysis of unialgal samples using high performance liquid chromatography (HPLC) with fluorescence and …

Aneuploidy Frequencies In Semen Fractions From Ten Oligoasthenoteratozoospermic Patients Donating Sperm For Intracytoplasmic Sperm Injection, Jerome Pfeffer, Myung-Geol Pang, Stanton F. Hoegerman, Christopher J. Osgood, M. W. Stacey, Jacob Mayer, Sergio Oehninger, William G. Kearns

Biological Sciences Faculty Publications

Objective: To determine aneuploidy frequencies in pellet and swim-up semen fractions from 10 infertile men with severe oligoasthenoteratozoospermia (OAT) who were donating sperm for intracytoplasmic sperm injection and to determine whether the swim-up isolation method would successfully separate aneuploid from haploid sperm.

Design: Prospective study.

Setting: Infertility clinic and molecular genetics laboratory.

Patient(s): Ten patients with severe OAT.

Intervention(s): Cytogenetic analyses by fluorescence in situ hybridization to determine aneuploidy frequencies for chromosomes 1, 13, 18, 21, X, and Y in sperm from swim-up and pellet fractions.

Main Outcome Measure(s): Gametic aneuploidy was scored in sperm fractions separated by the swim-up …

Studies On The Amylolytic Breakdown Of Damaged Starch In Cereal And Non-Cereal Flours, Karen Bailey

Masters

The term starch damage refers to a number of changes to the starch granule structure, which are detectable by different analytical techniques. Damaged starch is the substrate for amylases, which in turn provides carbohydrates that are used in the production of certain foods and food ingredients; as a result, therefore, determination of levels in flours is a procedure carried out routinely by many manufacturers of starch based products. Enzymatic assay methods emulate the susceptibility of damaged starch granules to enzymatic attack. The first aim of this study was to evaluate enzymatic methods(1,2) to determine damaged starch in wheat flours and …

Synthesis Of Benzoxazoles Containing Allyl Crosslinking Sites Via Claisen Rearrangements, Leslie K. Hutson

Browse all Theses and Dissertations

The reaction of diethyl 2,5-dihydroxyterephthalate with allyl bromide/K2CO3 in DMF followed by hydrolysis provided 2,5-di(allyloxy)terephthalic acid. The conversion of 2,5-di (allyloxy)terephthalic acid to 1,4-di(2-benzoxazolyl)-2,5-di(allyloxy)benzene in PPSE was unsuccessful. However, the reaction of 1,4-di(2-benzoxazolyl)-2,5- dihydroxybenzene with allyl bromide/K2CO3 provided 1,4-di(2-benzoxazolyl)-2,5- di(allyloxy)benzene. DSC analysis indicated that 1,4-di(2-benzoxazolyl)-2,5- di(allyloxy)benzene undergoes a Claisen rearrangement to the corresponding diallyl product. The synthesis of 2-allyloxy-1,4-di(2-benzoxazolyl)benzene was carried out using 2-hydroxy-1,4-di(2-benzoxazolyl)benzene as starting material. DSC analysis was inconclusive with respect to a Claisen rearrangement. The reaction of 2-allyloxybenzoic acid with 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane in PPSE was unsuccessful but the reaction of 2,2-bis(2-(2-hydroxyphenyl)-5-benzoxazolyl)-1,1,1,3,3,3-hexafluoropropane with allyl bromide/K2CO3 in DMF provided 2,2-bis(2-(2- …

Capillary Electrophoresis/Tandem Mass Spectrometry With Array Detection, L.J. Deterding, K.B. Tomer, J.M.Y. Wellemans, Ronald Cerny, M.L. Gross

Ronald Cerny Publications

Mixtures of standard compounds of biological interest were analyzed by capillary electrophoresis in conjunction with tandem four sector mass spectrometry (MS/MS) using an array detector. Capillary electrophoresis offers extremely high separation efficiencies while array detection allows for the simultaneous acquisition of a large fraction of a tandem mass spectrum and high utilization of the sample ions produced. Consequently, improvements in sensitivity and structural information were observed for the combined techniques in comparison to similar measurements with a four-sector and a single-point detector. Coaxial continuous-flow fast atom bombardment was used to create (M + H) precursor ions of the separated analyses …

Affinity Chromatography: A Review Of Clinical Applications, David S. Hage

David Hage Publications

Affinity chromatography is a type of liquid chromatography that makes use of biological-like interactions for the separation and specific analysis of sample components. This review describes the basic principles of affinity chromatography and examines its use in the testing of clinical samples, with an emphasis on HPLCbased methods. Some traditional applications of this approach include the use of boronate, lectin, protein A or protein G, and immunoaffinity supports for the direct quantification of solutes. Newer techniques that use antibody-based columns for on- or off-line sample extraction are examined in detail, as are methods that use affinity chromatography in combination with …

Pyrene Labeled Poly (Aryl Ether) Monodendrons: Synthesis And Photophysical Studies, Wajiha Adnan Khan

Seton Hall University Dissertations and Theses (ETDs)

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Use Of Excel To Obtain Voltammetric Information On Microelectrodes, Enda Howard, John Cassidy

Articles

The use of curve fitting for the analysis and interpretation of voltammetric data obtained while working with micro electrodes is discussed as a useful exercise for introducing students to the principle of problem solving using least-squares curve-fitting techniques. The advantages associated with this approach to data processing over the approach where the limiting current (i L) alone is used are discussed and its limitations are highlighted. This technique was applied to the determination of unknown concentrations of ferrocyanide and the most satisfactory recovery of concentrations was found when both the va1ues of the formal potential (EO') and concentration ( C) …

Investigating The Allosteric Behavior Of Malate Dehydrogenase From Escherichia Coli, Eman M. Ghanem

Masters Theses

Regulatory mechanisms of malate dehydrogenase from E.coli (eMDH) involving NADH as an allosteric effector were investigated. The reaction was studied in both directions: malate oxidation and oxaloacetate reduction. When malate was the variable substrate, a plot of rate against substrate concentration was sigmoidal in the presence of 0.065 mM NADH, which indicates the presence of an allosteric site for NADH on the enzyme. Binding of NADH at the allosteric site causes conformational changes in the active site and, thereby, changes the catalytic activity of the enzyme. An increase in K_m value, from 1.3 to 3.9 mM malate was observed, …

Optimization Of The Reaction Of Hexamethyldisilazane On A Fumed Silica Surface, Frederick R. Jones

Masters Theses

Hexamethyldisilazane (HMDS) is commonly used to transfer trimethylsilyl (TMS) groups to silica surfaces. While studies have been done examining individual factors that influence the reaction, no investigations have reported how these factors affect each other. The factors examined in this study include temperature, presence of catalyst (butylamine), pretreatment, time, concentration, solvent, and presence of water in the solvent. The purpose of this study is to examine potential factors and two-way interactions to determine which significantly affect the yield and produce an optimum set of conditions.

The HMDS reactions occurred in an organic solvent slurry under nitrogen. Using statistical experimental design, …

The Cytotoxicity And Mode Of Action Of 2,3,4-Trisubstituted Pyrroles And Related Derivatives In Human Tmolt4 Leukemia Cells, John T. Gupton, B. S. Burham, B. D. Byrd, K. E. Krumpe, C. Stokes, J. Shuford, S. Winkle, T. Webb, A. E. Warren, C. R. Barnes, J. Henry, I. H. Hall

Chemistry Faculty Publications

4-Carbechoxy-l-methyl-2-phenacyl-3-phenylpyrrole (9), 4-carbethoxy-2-(4-methoxybcnzoyl)-3-(4-methoxyphcnyl)pyrrole (10) and 2-(4-methoxybenzoyl)-3,4-bis-(4-methoxyphenyl)pyrrole (11) proved to be potent cytotoxic agents against the growth of murine and human leukemias and lymphomas. Selective toxicity was demonstrated against the growth of solid tumors, e.g. human adenocarcinoma of the colon SW480 and ileum HCT-8, glioma U-87-MG, and rat UMR-106 osteosarcoma. A mode of action study in Tmolt₄ leukemia cells demonstrated that the agents inhibited de novo purine synthesis at the regulatory sites PRPP-amido transferase, IMP dehydrogenase as well as dihydrofolate reductase resulting in significant inhibition of DNA synthesis in 60 min. Other biochemical sites …

Investigations Of A Phenanthroline-Based Azo Dye Ligand And Of Re(I) And Ru(Ii) Complexes Based On This Ligand, Yan Zhang

Masters Theses

A 1,10-phenanthroline based azo dye ligand, phen-azo-phenol, produced by diazotizing 5-amino-1,10-phenanthroline (5-NH₂-phen) and then coupling to phenol, and several transition metal complexes containing this ligand, have been synthesized and characterized. The phen-azo-phenol ligands attach to Re(I) and Ru(II) through the phenanthroline linkage to form stable polypyridyl complexes. These complexes show greatly enhanced absorption properties in the visible region when compared to the well-known analogous bipyridine and phenanthroline containing complexes. The visible light absorption of the free ligand and the complexes containing this ligand are greatly affected by the position of the deprotonation equilibrium of the -OH group on …

X-Ray Crystal Structures And The Facile Oxidative (Au−C) Cleavage Of The Dimethylaurate(I) And Tetramethylaurate(Iii) Homologues, Dunming Zhu, Sergey V. Lindeman, Jay K. Kochi

Chemistry Faculty Research and Publications

Dimethylaurate(I) has been prepared as the crystalline tetrabutylammonium salt for comparison with the known tetramethylaurate(III) analogue. The linear structure of dimethylaurate(I) and the square-planar structure of tetramethylaurate(III) have both been confirmed by X-ray crystallography. One-electron oxidation of dimethylaurate(I) by either ferrocenium or arenediazonium cations produces the metastable dimethylgold(II) intermediate, which can be trapped as the paramagnetic 9,10-phenanthrenequinone (PQ) adduct. Otherwise, dimethylgold(II) is subject to rapid reductive elimination of ethane and affords metallic gold (mirror). The analogous oxidation of tetramethylaurate(III) by ferrocenium, arenediazonium, or nitrosonium cations also proceeds via electron transfer to generate the putative tetramethylgold(IV) intermediate. The highly unstable (CH …

Neural Networks In The Analysis Of Water-Soluble Sulfonylurea Herbicides Using An Lc/Ms, Joseph Michael Pompano

Theses and Dissertations

In this research, a hidden node pruning algorithm was developed for an artificial neural network (ANN) that automatically determined a more efficient size of the hidden layer, caused the ANN to resize itself, and then continued to train using a standard back-propagation algorithm. The hidden-node pruning algorithm was based on determining the number of significant eigenvalues present in the matrix of values produced by the hidden layer, starting with an excessive number of hidden nodes.

Eight sulfonylurea herbicides were used as the target analytes in this study. The ability of an ANN to simplify the sample preparation needed for analysis …

Adventures In Fire Retardancy, Charles A. Wilkie

Chemistry Faculty Research and Publications

The work of the author's research group on fire retardancy over the past twenty years is reviewed.

Portfolio Assessment In High School Chemistry, Mark M. Laporte

Dissertations and Theses @ UNI

This is a report of one high school chemistry teacher's experience of implementing portfolio assessment in his classroom. This project was carried out using a teacher as researcher model. The chemistry classes were p1imarily composed of 11th grade students in a rural midwestern high school setting. This thesis reviews some of the literature regarding alternative assessment focusing particularly on the literature related to portfolio assessment. The chemistry portfolio design is explained in detail including a rationale for each of the portfolio elements. The teacher developed nine portfolio elements of which the students were required to complete five. The nine elements …

Photodecolorization And Photodegradation Of Crystal Violet Adsorbed On Metal Oxide Surfaces, Reygan Mashay Freeney

Dissertations and Theses @ UNI

The photodecolorization and the photodegradation of the triphenylmethane dye crystal violet (basic violet 3) adsorbed on four metal oxide catalysts was studied. Crystal violet dissolved in methanol was adsorbed onto the surfaces of an anatase and rutile titanium dioxide mixture, rutile titanium dioxide, zinc oxide, and magnesium oxide, and the solvent was allowed to evaporate. The samples were irradiated using a 1000 W mercury-xenon arc lamp with glass optics as a light source. A wide spectrum and narrow regions of the spectrum were studied to determine their impact on the decolorization and degradation of crystal violet. Diffuse reflectance spectroscopy was …

Degradation Of Explosives In Solution Using Bacteria, A Fungus (Phanerochaete Chrysosporium), Titanium Dioxide, Ozone, And Electrochemical Peroxidation, Stéphane Debost

Dissertations and Theses @ UNI

As a result of munitions manufacturing and decommissioning, explosive compounds have contaminated groundwater and soils at many sites throughout the U.S. and worldwide. Three of the most commonly occurring explosive contaminants are TNT, ROX, and HMX. Many processes, biological as well as physical, have been developed to remediate the contaminated material. But feasibility studies rarely take into account the three contaminants at once. We chose four of the technologies used to remediate explosives-contaminated water and studied comparatively their effectiveness and efficiency in degrading TNT, ROX, and HMX in solution at their maximal solubilities. The chosen technologies were bacterial and fungal …

Improved Properties Of Taox Films Doped With Al And N, Robert B. Van Dover, Lynn Schneemeyer, R. M. Fleming, D. J. Werder

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Simultaneous addition of Al and N to Ta-O thin films is found to significantly improve the dielectric properties of the films. Specifically, substitution of 10-40 at. % Al for Ta along with approx. 2 at. % N for O is found to decrease the density of catastrophic defects in the films, resulting in high and statistically more uniform breakdown voltages. This conclusion is based on evaluation of approx. 750 individual capacitors in each experiment.