Chemistry Commons^™

Understanding Rapid Intercalation Materials One Parameter At A Time, Wessel Van Den Bergh, Morgan Stefik

Faculty Publications

Demand for fast, energy-dense storage drives the research into nanoscale intercalation materials. Nanomaterials accelerate kinetics and can modify reaction path thermodynamics, intercalant solubility, and reversibility. The discovery of intercalation pseudocapacitance has opened questions about their fundamental operating principles. For example, are their capacitor-like current responses caused by storing energy in special near-surface regions or rather is this response due to normal intercalation limited by a slower faradaic surface-reaction? This review highlights emerging methods combining tailored nanomaterials with the process of elimination to disambiguate cause-and-effect at the nanoscale. This method is applied to multiple intercalation pseudocapacitive materials showing that the timescales …

High Performance Liquid Chromatography Monitoring Reaction Kinetics, Ken Overway, Mary Ruth Shifflett

Chemistry Faculty Scholarship

To develop a chromatographic method to characterize enantioselective kinetics, the reaction between aromatic aldehydes and ephedrine will be monitored with High Performance Liquid Chromatography (HPLC). First, develop kinetics analysis procedure with the HPLC, the decomposition of aspartame was observed with citrate and phosphate buffers. The procedure produced an activation energy in the presence of phosphate buffer of 71.9 kJ/mol with a -0.126 % error. The aromatic aldehyde, benzaldehyde, and ephedrine were run through a stereospecific column to separate peaks with various mobile phases. A more nonpolar mobile phase is required for better peak and retention time separation.

Growth Kinetics Determine The Polydispersity And Size Of Pbs And Pbse Nanocrystals, Michael P. Campos, Jonathan De Roo, Matthew W. Greenberg, Brandon M. Mcmurtry, Mark P. Hendricks, Ellie Bennett, Natalie Saenz, Matthew Y. Sfeir, Benjamin Abecassis, Sanjit K. Ghose, Jonathan S. Owen

Advanced Science Research Center

A library of thio- and selenourea derivatives is used to adjust the kinetics of PbE (E = S, Se) nanocrystal formation across a 1000-fold range (kr = 10−1 to 10−4 s−1), at several temperatures (80–120 °C), under a standard set of conditions (Pb : E = 1.2 : 1, [Pb(oleate)2] = 10.8 mM, [chalcogenourea] = 9.0 mM). An induction delay (tind) is observed prior to the onset of nanocrystal absorption during which PbE solute is observed using in situ X-ray total scattering. Density functional theory models fit to the X-ray pair distribution function (PDF) support a Pb2(μ2-S)2(Pb(O2CR)2)2 structure. Absorption spectra …

Parametric And Kinetic Study Of Solvent-Free Synthesis Of Solketal Using Ion Exchange Resin, Dheer A. Rambhia, Sravanthi Veluturla, Archna Narula

Turkish Journal of Chemistry

The ketalization reaction of glycerol with acetone for solketal formation was performed using a gel-type ion exchange resin, Indion 225H in a solvent-free medium. The experimental parameters molar ratio, catalyst loading, rate of stirring, and temperature were analyzed and evaluated for their impact on the conversion of glycerol. A kinetic model based on the Langmuir-Hinshelwood?Hougen- Watson (LHHW) equation described the kinetics of the heterogeneous system. The parameters were evaluated using the ode45 solver and Genetic Algorithm (GA) optimization function on MATLAB software. The activation energy for the ketalization of glycerol was found to be 39.3 kJ/mol, the enthalpy of adsorption …

Kinetic, Isotherm, And Thermodynamic Studies For Adsorptive Removal Of Basic Violet 14 From Aqueous Solution, Yasemi̇n Tamer, Hale Berber

Turkish Journal of Chemistry

In this study, the performance of chitosan based semi-IPN nanocomposite hydrogels for the adsorptive removal of basic violet 14 (BV14) from aqueous solution has been explored. Batch adsorption studies were conducted to determine the effect of various parameters on BV14 adsorption, and optimum values were reported as pH of 8, the adsorbent dosage of 0.025 g, initial BV14 concentration of 5 mg L^-1 and contact time of 90 min at a temperature of 25 °C. The semi-IPN hydrogel containing 0.5% by weight GO showed the improved adsorption capacity for BV14 compared to the neat hydrogel adsorbent, and the maximum …

Analysis Of Copper(Ii) Using The Ascorbate/Oxygen System – A Valuable Undergraduate Resource, Sean Tobin, John Cassidy, Kevin Kurian, Tony Betts

Articles

In deionised water, ascorbic acid (AH−), through oxidation by oxygen in the presence of copper(II), was found to degrade with zero-order kinetics. The magnitude of the reaction rate varied directly with the copper(II) concentration. At a higher pH (7.4), the same reaction was found to be pseudo-first order. Once again, the magnitude of the rate increased linearly with copper(II) concentration at a micromolar level. Dissolved oxygen levels, in excess AH− and trace copper(II), displayed similar kinetics under both conditions. Monitoring of either AH− levels or dissolved oxygen concentration was found to be a useful novel undergraduate practical laboratory for trace …

Study Of Resonantly Stabilized Radicals In Combustion Environments, James H. Lee

Graduate Theses, Dissertations, and Problem Reports (ETD)

Resonantly stabilized radicals (RSRs) play an important role in combustion environments due to their high stability resulting from resonance. Many RSRs such as the propargyl, allyl, or benzyl radicals are precursors to the formation of polycyclic aromatic hydrocarbons (PAHs), which can aggregate to form soot. Due to their stability, these RSRs can accumulate in combustion environments in significant quantities. The primary way these radical species are consumed in flames or by reactions with other abundant radicals, by self-recombination of propargyl to form benzene, or in the form of other abundant radicals such as the hydroxyl radical. Experimentally determining the pathways …

Visible Light Generation And Mechanistic Investigation Of High-Valent Metal-Oxo Species Supported By Different Ligands, Seth Ellis Klaine

Masters Theses & Specialist Projects

Numerous transition metal catalysts have been designed as biomimetic model compounds for the active site of metalloenzymes found throughout Nature, most notably cytochrome P450 monooxygenases that carry out the oxidative transformations of organic substrates with near-perfect chemo-, regio-, and stereo-selectivity. The primary active oxidants in catalytic and enzymatic cycles are fleeting high-valent metal-oxo intermediates where the oxo ligand can transfer to an organic substrate in a process known as oxygen atom transfer (OAT).

In the present work, porphyrin-manganese(III), salen-chromium(III), and salenmanganese( III) derivatives were successfully synthesized and spectroscopically characterized using 1H NMR and UV-Vis spectroscopies. A facile photochemical approach was …

Process Optimization And Mechanism Study Of Acid Red G Degradation By Electro-Fentonfeox Process As An In Situ Generation Of H2o2, Hailong Sun, Yingwu Yao, Feng Wei, Qiang Zhao, Baichen Liu, Liman Zhang

Turkish Journal of Chemistry

Dye-contaminated wastewaters are industrial wastewaters that are difficult to treat using traditional biochemical and physicochemical methods. In the present work, the acid red G was removed as a model pollutant by the electro-Fenton process for the first time. The anode and cathode used by the electro-Fenton process were iron plate and graphite felt, respectively. It was concluded that under the optimal conditions of current density = 20 mA cm-2, pH = 3 and initial Na2SO4 concentration = 0.2 M, the removal rate of acid red G (ARG) with an initial concentration of 300 mg L-1 could reach 94.05% after 80 …

Modeling Mass Transfer And Chemical Reaction In Industrial Nitrocellulose Manufacturing Processes, Francis Patrick Sullivan

Dissertations

A series of models are proposed to describe the production of military grade nitrocellulose from dense cellulose materials in mixtures of nitric acid, sulfuric acid, and water. This effort is conducted to provide a predictive capability for analyzing the rate and extent of reaction achieved under a range of reaction conditions used in the industrial nitrocellulose manufacturing process for sheeted cellulose materials. Because this capability does not presently exist, nitrocellulose producers have historically relied on a very narrow range of cellulose raw materials and resorted to trial and error methods to develop processing conditions for new materials. This tool enables …

Synthesis, Characterization, And Kinetics Studies Of New Cobalt Complexes For The Production Of H2 In Acidic Media, Michael John Celestine

Chemistry & Biochemistry Theses & Dissertations

The kinetics and mechanism of the oxidation of [Co(dmgBF₂)₂(OH₂)₂] (where dmgBF₂ = difluoroboryldimethylglyoximato) by sodium hypochlorite (NaOCl), sodium bromate (NaBrO₃), and bromine (Br₂₎ was investigated by stopped-flow spectrophotometry at 450 nm over a wide temperature range. The pK_a1 value for [Co(dmgBF₂)₂(OH₂)₂] was calculated as 5.27 ± 0.14 at I = 0.60 (NaCl). From the variation in pH studies, the activation parameters were derived from the proposed mechanisms for NaOCl, ΔH_1*, ΔH_2*, ΔS_1*, and …

Chloramination Of Iopamidol- And Bromide-Spiked Waters Containing Natural Organic Matter, Nana Osei B Ackerson, Hannah K. Liberatore, Susan D. Richardson, Micheal J. Plewa, Thomas A. Ternes, Stephen E. Duirk

Faculty Publications

Iopamidol (an iodinated X-ray contrast medium) and bromide are precursors in the formation of halogenated disinfection byproducts (DBPs). The interactions of these precursors are vital to elucidate the formation of halogenated DBPs during chloramination. This work investigated the formation of total organic halogen and select individual DBPs in two laboratory-chloraminated source waters containing iopamidol and bromide. Experiments were carried out in batch reactors containing Barberton source water (BSW) and Cleveland BSW (CSW), spiked with iopamidol (5 mu M), bromide (15 mu M), and 100 mu M monochloramine. Total organic iodine concentrations were approximately equal regardless of source water since they …

Aqueous Kinetics Of Α-Hydroxyhippuric Acid Derivatives Bearing Electron-Withdrawing Groups As A Function Of Ph And Buffer Catalysts, Mohamad Imad Rafie

Theses and Dissertations

It has been shown that carbinolamides are intermediates in the enzyme-catalyzed synthesis of -amidated peptides. Although carbinolamides are important intermediates in the production of these hormones and have roles in other biological venues, little attention has been given to their mechanisms of reaction in water, and, thus, it is difficult to speculate how their reaction would be enzymatically catalyzed. The purpose of the work presented here was to synthesize structural analogs of the biological intermediates and study their mechanism of breakdown in water. -Hydroxyhippuric acid, a substrate for the enzymatic system, provides an easily modified template for the study of …

Cellulose-Based Doped Carbon Materials For Removal Of Nitrophenols From Water, Ambar Bahadur Rangu Magar

Theses and Dissertations

Nitrophenols (NPs) and their derivatives are highly toxic, mutagenic, and bio-refractory pollutants commonly present in natural water resources and industrial wastewater. Various types of materials and methods have been practiced removing the NPs from polluted water. In this research, we are focusing on synthesizing of inexpensive doped carbon-based materials using renewable and biodegradable polymers such as microcrystalline cellulose and nanocrystalline cellulose. Current work has been undertaken to develop doped carbon-based materials using a low-cost and straightforward method and characterized using different analytical techniques. The synthesized materials were used for the sustainable and efficient removal of NPs from an aqueous environment …

Non-Canonical Targets, Reaction Kinetics, And Cellular Potency Of Amino Acid-Linked Platinum(Ii) Compounds, Bett Kimutai

Wayne State University Dissertations

DNA serve as an ideal target where drugs such as cisplatin (cisPt) bind and exert their anticancer activities. CisPt is known to preferentially coordinate with DNA leading to formation of cisPt-deoxyguanosine (dGuo) adducts. The adducts distort the DNA structure and contribute to inhibition of DNA-mediated cellular functions and ultimately cancer cell death. Despite its utilization as an anticancer drug, cisPt has a number of drawbacks, which include toxic side effects and cellular resistance. Resistance occurs through processes such as repair of damaged DNA and inactivation of cisPt present in the cell. To overcome these challenges, the aim of this thesis …

Leaving Ligand Effects On Reactivity And Solubility Of Monofunctional Platinum(Ii) Anticancer Complexes, Heidi Linn Hruska Millay

Masters Theses & Specialist Projects

Monofunctional platinum(II) complexes, such as phenanthriplatin and pyriplatin, have notably different characteristics from the bifunctional anticancer complexes, such as cisplatin and oxaliplatin, which have detrimental toxicities and resistance associated with them. The unique properties of the monofunctional complexes may be exploited to target cancer cells without producing the toxic side effects associated with the current FDA-approved platinum-based anticancer drugs. To advance the understanding of these monofunctional platinum(II) complexes, this study replaced the chloride leaving ligand with an acetate group, which should increase solubility and alter the rate of reactivity with key amino acid and nucleotide targets. Phenanthriplatin and pyriplatin compounds …

State-To-State Inelastic Rotational Cross Sections In Five-Atom Systems With The Multiconfiguration Time Dependent Hartree Method, Steve Ndengue, Yohann Scribano, Fabien Gatti, Richard Dawes

Chemistry Faculty Research & Creative Works

We present a MultiConfiguration Time Dependent Hartree (MCTDH) method as an attractive alternative approach to the usual quantum close-coupling method that approaches some computational limits in the calculation of rotational excitation (and de-excitation) between polyatomic molecules (here collisions between triatomic and diatomic rigid molecules). We have performed a computational investigation of the rotational (de-)excitation of the benchmark rigid rotor H₂O-H₂ system on a recently developed Potential Energy Surface of the complex using the MCTDH method. We focus here on excitations and de-excitations from the 0₀₀, 1₁₁, and 1₁₀ states of H_{2 …}

Designing, Constructing, And Employing Two-Dimensional Ultrafast Spectroscopy To Resolve Complex Kinetics, Jason R. Darvin

Theses and Dissertations

Multiple population-period transient spectroscopy (MUPPETS) is a two dimensional ultrafast time resolved spectroscopy technique. MUPPETS uses three pairs of optical pulses over two time periods to separate homogeneous and heterogeneous causes of rate dispersion. This dissertation details improvements to the MUPPETS optical assembly enabling measurements on systems that previously fell outside of the MUPPETS 2-ns time window. In addition, the theoretical groundwork is laid to unveil the hidden coordinate controlling rate exchange using 2D and 3D correlation functions.

The first project details improvements made to the MUPPETS assembly. A detailed method was developed to eliminate astigmatism, coma, and spherical aberration …

Sorption Of Copper (Ii), Nickel (Ii) And Cobalt (Ii) Ions Into The Ionite Modified By Polyphinylchloride And Polyethylene Polyamine, Kh Ismoilova, D Bekchanov, Sh Khasanov, M Baltaeva

Scientific journal of the Fergana State University

IPolyphinylchloride was modified by polyethylene polyamine, and the ionites were studied in static conditions by the artificial solution of copper (II), nickel (II) and cobalt (II) ions. In static conditions, factors affecting the sorption process, such as time, temperature and concentration dependence were investigated. The results of the inquiry process were studied by IR analysis

Sorption Of Copper (Ii), Nickel (Ii) And Cobalt (Ii) Ions Into The Ionite Modified By Polyphinylchloride And Polyethylene Polyamine, Kh Ismoilova, D Bekchanov, Sh Khasanov, M Baltaeva

Scientific journal of the Fergana State University

IPolyphinylchloride was modified by polyethylene polyamine, and the ionites were studied in static conditions by the artificial solution of copper (II), nickel (II) and cobalt (II) ions. In static conditions, factors affecting the sorption process, such as time, temperature and concentration dependence were investigated. The results of the inquiry process were studied by IR analysis

Kinetic Study Of Silver Nanoparticle Formation, Steven A. Diaz

Ursidae: The Undergraduate Research Journal at the University of Northern Colorado

With the increased use of silver nanoparticles in modern day applications, kinetic information on the mechanism of their formation is useful for further studies on its reactivity in a biological environment. Silver nanoparticles were synthesized using a modified Turkevich method. The synthesized nanoparticles were characterized using UV-Visible spectroscopy. The data obtained were plotted as a function of time, and rate constants for the nucleation (k₁) and autocatalytic surface growth (k₂) were extracted. Comparing the k₁ (~10^-3) and k₂ (~10^-1) values supports a two-step mechanism of slow nucleation and fast autocatalytic …

An Evaluation Of The Adsorption Dynamics Of Phosphate Ions Onto Fe(Ii)-Montmorillonites, Dawei Qin, Shuhua Chang, Min Qiao, Xiaotong Yuan, Wei Liu, Gang Liu

Turkish Journal of Chemistry

Fe(II)-montmorillonites (Fe(II)-MMTs) were prepared by mixing solutions of Fe(II) and montmorillonite at pH 3.5. Two different Fe(II)-MMTs were prepared and the ferrous iron contents were 40 mg/L and 80 mg/L. All samples were characterized by XRD, FT-IR, TGA, DSC, and nitrogen adsorption. By nitrogen adsorption, the pore size can be obtained in the pore diameter curve with average pore widths of 6.67 nm, 9.96 nm, and 17.07 nm, respectively. The removal rate of phosphate increased rapidly during the first 40 min, in which Fe(II)-MMT (1) and Fe(II)-MMT (2) were stronger adsorption systems than MMT. The maximum adsorption was 48.38 mg/g …

Experimental And Modeling Investigation Of The Oh-Initiated Oxidation Of Semi-Solid And Aqueous Saccharide Aerosols, Hanyu Fan

Graduate Theses, Dissertations, and Problem Reports (ETD)

My research focuses on investigating the impact of moisture-induced and oligomer-induced viscosity changes on OH-initiated oxidation of semi-solid aerosols,and the role of gas-liquid interfaces in regulating aqueous aerosol chemistry. Saccharides, which are a major constituent of aqueous atmospheric aerosols, are chosen as model molecules to form highly oxygenated organic aerosols. The experiments are performed using an atmospheric pressure flow-tube reactor with both online VUV-AMS (Vacuum-Ultraviolet Aerosol Mass Spectrometer) and offline GC-MS analysis techniques. The decay rates of saccharide are determined by measuring the loss signal of saccharide in the particle phase as a function of OH exposure (time-integrated total concentration …

Non-Covalent And Covalent Interactions Between Phenylacetylene And Quinoline Radical Cations With Polar And Non-Polar Molecules In The Gas Phase, Adam C. Pearcy

Theses and Dissertations

Gas phase molecular clusters present an ideal medium for observing factors that drive chemical reactions without outside interferences from excessive solvent molecules. Introducing an ion into the cluster promotes ion-molecule interactions that may manifest in a variety of non-covalent or even covalent binding motifs and are of significant importance in many fields including atmospheric and astronomical sciences. For instance, in outer space, molecules are subject to ionizing radiation where ion-molecule reactions become increasingly competitive to molecule-molecule interactions. To elucidate individual ion-molecule interaction information, mass spectrometry was used in conjunction with appropriate theoretical calculations.

Three main categories of experiment were conducted …

H2 Oxidation Over Supported Au Nanoparticle Catalysts: Evidence For Heterolytic H2 Activation At The Metal-Support Interface, Todd N. Whittaker, K. B. Sravan Kumar, Christine Peterson, Meagan N. Pollock, L. C. Grabow, Bert D. Chandler

Chemistry Faculty Research

Water adsorbed at the metal-support interface (MSI) plays an important role in multiple reactions. Due to its importance in CO preferential oxidation (PrOx), we examined H₂ oxidation kinetics in the presence of water over Au/TiO₂ and Au/Al₂O₃ catalysts, reaching the following mechanistic conclusions: (i) O₂ activation follows a similar mechanism to that proposed in CO oxidation catalysis; (ii) weakly adsorbed H₂O is a strong reaction inhibitor; (iii) fast H₂ activation occurs at the MSI, and (iv) H₂ activation kinetics are inconsistent with traditional dissociative H₂ chemisorption on metals. Density …

Development Of Rapid, Homogeneous Assay For Investigating Isopeptide Bond Formation Using Fluorescence Polarization/Depolarization Measurements, Samuel Patricc Kasson

Graduate Theses/Dissertations

Autocatalytic intramolecular isopeptide bonds have been found in nature in certain gram-positive bacterial pilus structures. Recently, splitting of these domains that are capable of autocatalytic intramolecular isopeptide bond formation have been applied to create stable, selective, bio-orthogonal Catcher/Tag systems. The CnaB2 domain found in the FbaB pilus structure of Streptococcus pyogenes, has yielded the Catcher/Tag, Protein/Peptide systems termed SpyCatchter and SpyTag. Recent study has focused on tag optimization, stability and bio-orthogonality evaluation, along with applications in bioconjugation. I have recombinantly expressed SpyCatcher and SpyTag-fused proteins in E.coli, and conjugated them to fluorescent probes in order for use in fluorescence polarization/depolarization …

Kinetics And Activation Energy Parameters For Hydrolysis Of Acetic Anhydride In A Water-Acetone Cosolvent System, Samson Olowoyo

Electronic Theses and Dissertations

The hydrolysis of acetic anhydride is a widely-studied liquid phase reaction studied since 1906. Different approaches have been used to study the kinetics of this reaction. Approaches used by researchers have involved the use of sophisticated experimental set-ups. In this work, the pH technique has been adopted which involves the use of a pH meter to monitor the hydrolysis reaction. Analysis of the hydrolysis reaction has been performed for water/acetone cosolvent systems over a range of temperatures and mole fractions. Eyring analysis was performed under isomole fraction conditions and activation enthalpy, entropy, and Gibbs free energy for hydrolysis of acetic …

Removal Of Chromium(Vi) And Chromium(Iii) Ions From Aqueous Solution Using Bio-Char Generated From Agricultural Waste Products, Diego Fernando Gonzalez

Theses and Dissertations

Heavy metals are one of the most persistent and prevalent contaminants in the aquatic environment. The removal of chromium from aqueous solution, especially in the hexavalent form is difficult. New technologies, techniques and/or new materials have been designed in order to effectively and efficiently remove chromium from the aqueous environment. The project focuses on the comparison of the effects of pH, time, temperature, binding capacity on bio-char’ generated from agricultural waste produces vs an amino modified derivative of the bio-char. Pineapple skins were dried, ground, sieved, and pyrolyzed to produce a bio-char material. The bio-char was analyzed using FTIR to …

Kinetics Of Silver(I)-Catalyzed Oxidation Of Allyl Alcohol By Peroxodiphosphate Inacetate Buffers, Priyamvada Sharma, Riya Sailani, Deepmala Pareek, Chandra Lata Khandelwal

Turkish Journal of Chemistry

The kinetics and mechanism of silver(I)-catalyzed oxidation of allyl alcohol with peroxodiphosphate in acetate buffers have been studied. The rate is independent of allyl alcohol concentration. The effect of other reaction parameters such as hydrogen and acetate ions has also been studied. The rate law accounting for all experimental observations corresponds to the proposed mechanism. The energy and entropy of activation have also been evaluated by employing Eyring plots.

Experimental And Theoretical Study Of Nh$_{3}$ Adsorption And Desorption Over A Cu-Chabazite Nh$_{3}$-Scr Catalyst, Selmi̇ Eri̇m Bozbağ, Mutlu Şi̇mşek, Onur Demi̇r, Deni̇z Şanli Yildiz, Hüseyi̇n Barkin Özener, Gökhan Hi̇sar, Can Erkey

Turkish Journal of Chemistry

NH$_{3}$ adsorption and desorption behavior of a commercial Cu-chabazite (CHA) NH$_{3}$ selective catalytic reduction (NH$_{3}$-SCR) catalyst was studied in the presence and absence of H$_{2}$O. NH$_{3}$ uptake values at various adsorption temperatures were obtained during various steps of the adsorption and temperature-programmed desorption (TPD) experiments. Total NH$_{3}$ uptake decreased from 4.6 to 1.6 g NH$_{3}$/L catalyst when the adsorption temperature was increased from 50 to 300 $^{\circ}$C. Three major adsorption sites for NH$_{3}$ adsorption could be identified and quantified using TPD experiments, namely loosely, moderately, and strongly bound NH$_{3}$ with peak centers at around 147, 266, and 447 $^{\circ}$C. The …