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Articles 1351 - 1380 of 1398
Full-Text Articles in Chemistry
An Investigation Of Solvent Extraction Techniques In The Determination Of Formation Constants Of Complex Species In Aqueous Silver Chloride Solution, David Martin Bodily
An Investigation Of Solvent Extraction Techniques In The Determination Of Formation Constants Of Complex Species In Aqueous Silver Chloride Solution, David Martin Bodily
Theses and Dissertations
Solvent extraction techniques have been used to determine formation constants for molecular silver chloride and dichloro silver (I) ion in unsaturated aqueous solutions. Nitrobenzene was used to extract the molecular silver chloride from the aqueous silver chloride solution. The total concentration of silver in each phase was determined by radioassay techniques and related by an expression involving the equilibrium constants. The reciprocal of the distribution ratio times the activity of the chloride ion was plotted versus the activity of the chloride ion and portions of the curve were analyzed by the method of least squares to obtain values for the …
An Investigation Of The Formation Constant Of Molecular Silver Chloride Using Ion Exchange Techniques.|Nii.|Pan Investigation Of The Rate Of Precipitation Of Silver Sulfide By Thioacetamide, James W. Pyper
Theses and Dissertations
The first part of this work reports on the investigation of the formation constant of molecular silver chloride using ion exchange techniques. In order to determine the formation constant, it was necessary to develop a method of rinsing the sorbed molecular silver chloride from the resin. It was found that desorption with nitrobenzene would remove the sorbed molecular species. However, the formation constant was not calculated since the nitrobenzene used contained hydrogen ion and chloride ion which removed silver ion as well as the molecular species. In the study of the formation of silver sulfide by the reaction between the …
The Cytochrome Composition Of Bacillus Subtilis And Bacillus Megaterium, John Harvey Mangum
The Cytochrome Composition Of Bacillus Subtilis And Bacillus Megaterium, John Harvey Mangum
Theses and Dissertations
A spectroscopic and enzymatic investigation of the cytochromes of B. megaterium and B. subtilis was conducted. Attempts were made to isolate and characterize the individual cytochromes as well as to determine the locale of such activities as cytochrome c oxidase, DPNH oxidase, succinic dehydrogenase, cytochrome c reductase and diaphorse. Only two methods proved effective in liberating the cytochromes; disruption of the cells with sonic osillations and grinding tlhe cells with alumina. These procedures caused a fragmentation of the cell membrane. It was found that the entire cytochrome complement of these two bacteria was bound intimately to particles which most likely …
An Investigation Of Metallic Rhenium, Rhenium Dioxide And Rhenium Chlorides As Catalysts In The Hydrogenation Of Certain Organic Substrates, Walter William Brown
An Investigation Of Metallic Rhenium, Rhenium Dioxide And Rhenium Chlorides As Catalysts In The Hydrogenation Of Certain Organic Substrates, Walter William Brown
Theses and Dissertations
The purpose of the present investigation was to examine the various analytical methods to ascertain the suitability of the methods for our use in determining the amount of rhenium used in our catalysts, and, if necessary devise a new method. Also, several catalysts were to be prepared and used in hydrogenation or organic compounds. Evaluation of the catalytic activity of each catalyst was to be made by using them with various selected organic substrates.
The Kinetics Of Thermal Decomposition Of 1,1'-Azobutane, 1,1'-Azoisobutane And 2,2'-Azobutane, Norman L. Eatough
The Kinetics Of Thermal Decomposition Of 1,1'-Azobutane, 1,1'-Azoisobutane And 2,2'-Azobutane, Norman L. Eatough
Theses and Dissertations
The following compounds have been prepared and purified and the boiling points, densities, refractive indicies and infrared spectra of each have been determined and recorded: n-butyraldazine, isobutyraldazine, methylethyl ketazine, 1,2-di-n-butylhydrazine, 1,2-diisobutylhydrazine, 1,2-di-sec.-butylhydrazine, 1,1'-azobutane, 1,1'-azoisobutane and 2,2'-azobutane. Vapor pressure curves and freezing points of 1,1'-azobutane, 1,1'-azoisobutane and 2,2'-azobutane have been determined and recorded. The kinetics of thermal decomposition of 1,1'-azobutane, 1,1'-azoisobutane, and 2,2'-azobutane in a flow system using hydrogen and helium as a carrier gases have been investigated. The investigation was carried out for two different concentrations of the azo compounds over a pressure range of 670 to 890 mm. Hg …
An Investigation Of Complex Species In Silver Chloride Solutions I. Solubility Measurements ; Ii. Ion Exchange Methods, Harry G. Hecht
An Investigation Of Complex Species In Silver Chloride Solutions I. Solubility Measurements ; Ii. Ion Exchange Methods, Harry G. Hecht
Theses and Dissertations
The complex species in silver chloride solutions have been investigated by solubility measurements and by ion exchange methods in this work. The solubility of silver chloride in solutions of varying chloride ion concentrations was determined by radioassay techniques. The method of least squares was used to evaluate the constants for the formation of the aqueous silver chloride and the dichloro-complex species; the values being 1.99 x 103 and 2.98 x 104, respectively, at 25.00°C. Aqueous solver chloride has been shown to be sorbed by Amberlite IR-120 from silver chloride solutions which have an ionic strength of 0.2. This sorption has …
Decahydroquinoxaline : Stereoisomers And Derivatives, Lynn Pendleton
Decahydroquinoxaline : Stereoisomers And Derivatives, Lynn Pendleton
Theses and Dissertations
The preparation of decahydroquinoxaline by four different methods, with no determination of geometrical configuration made, was reported in the literature. The purpose of this thesis was to establish the geometrical configurations of the decahydroquinoxalines prepared by these four methods and to determine if, as the work of previous investigators suggested, the two pure isomers of decahydroquinoxaline isomerized, each giving an equilibrium mixture of both isomers. Decahydroquinoxaline was prepared by three of the four previously reported methods of preparation. Comparison of the properties of the decahydroquinoxalines prepared and the preparation, comparison, and analyses of the diacetyl and the dinitroso derivatives of …
Rhenium Trioxide, Rhenium Heptoxide And Rehnium Trichloride As Hydrogenation Catalysts, William J. Bartley
Rhenium Trioxide, Rhenium Heptoxide And Rehnium Trichloride As Hydrogenation Catalysts, William J. Bartley
Theses and Dissertations
The purpose of this study was to characterize the catalytic activity of rhenium trioxide and rhenium trichloride as hydrogenation catalysts. Work was also undertaken to further study the catalytic properties of rhenium heptoxide. The activity of this latter compound had received some study in a previous project. A complete review of the literature has been made on the organic and inorganic chemistry of rhenium trioxide and rhenium trichloride. A survey of the literature on catalytic hydrogenation and the chemistry of rhenium heptoxide has also been included. Rhenium trioxide was prepared by three similar methods. The first two involved the formation …
The Bromination Of 1,1,1-Ethanetriacetic Acid, John A. Gurney
The Bromination Of 1,1,1-Ethanetriacetic Acid, John A. Gurney
Theses and Dissertations
Essential to the entire field of Organic Chemistry is the nature of the carbon to carbon bond. Our current concepts and guiding principles concerning it are almost solely constructed from aliphatic compounds, certain simple ring species, and aromatic systems. Except for special cases, aliphatic and aromatic types are felt to be mildly strained or free from internal tension while the alicylic small and medium ring compounds are the so-called strained molecules. These strained compounds involve bending back or compression of two of the four carbon bonds from an equilibrium position. Distortions of more complex origin occur in the paracyclophanes and …
The Photoreduction Of Indigo Carmine Flavin Mononucleotide And Diphosphopyridine Nucleotide, By Illuminated Chloroplasts, M. Odell Hobbs
The Photoreduction Of Indigo Carmine Flavin Mononucleotide And Diphosphopyridine Nucleotide, By Illuminated Chloroplasts, M. Odell Hobbs
Theses and Dissertations
An investigation was made of the photoreduction of indigo carmine dye and flavin mononucleotide (FMN) by an illuminated sugar beet leaf homogenate in the presence of 2,6-dichlorophenolindophenol dye (DPIP) and ascorbic acid. DPIP and ascorbate were absolutely required for the reaction. Reconstitution experiments indicated a requirement for a heat-labile factor present in the supernatant fluid following centrifugation of the leaf homogenate. This factor activated the photoreduction of indigo carmine more than 20 times. The photoreduction of FMN was activated 2 times by this factor. Studies on the stoichiometry of indigo carmine photoreduction revealed that one mole of ascorbate was photooxidized …
Rhenium Catalysis I. Hydrogenation And Hydroformylation Using Rhenium Carbonyl Compounds ; Ii. Hydrogenation Using Catalysts Obtained From The Reduction Of Perrhenates With Metals In Aqueous Solution, Terry G. Selin
Theses and Dissertations
The purpose of this work was to investigate the catalytic activity in both hydrogenation and hydroformylation reactions of rhenium preparations which have not been previously characterized. Rhenium pentacarbonyl was prepared in good yield from rhenium heptoxide and carbon monoxide. The optimum conditions for preparation were 25 hours per gram of dry rhenium heptoxide at 250° under 3000 psig. (initial) of carbon monoxide. Rhenium chloropentacarbonyl was prepared in 62% yield from potassium chlororhenite and carbon monoxide at high temperatures and pressures. The iodopentacarbonyl was prepared in 29% yield from potassium perrhenate, methyl iodide, and carbon monoxide. The preparation of rhenium hydrocarbonyl …
The Preparation And Catalytic Properties Of Rhenium Blacks Obtained By Reduction Of Re(Vii) In Anhydrous Ammonia And Amines With Alkali Metals, David William Seegmiller
The Preparation And Catalytic Properties Of Rhenium Blacks Obtained By Reduction Of Re(Vii) In Anhydrous Ammonia And Amines With Alkali Metals, David William Seegmiller
Theses and Dissertations
The purpose of the investigation was to determine the catalytic activity of rhenium blacks obtained by reduction of rhenium salts in alkali metal-ammonia or amine systems. A review is presented on the chemical, physical and catalytic properties of rhenium, and on the rhenide ion, on the nature of the alkali metal-liquid ammonia system, and the reduction of metallic salts therein. The first reduction system studied was that obtained by dissolving sodium in liquid ammonia. The salts reduced in this system were KReO_4, Re_2O_7 and NH_4ReO_4. The reduction of KReO_4 was unsuccessful, and the heptoxide was difficult to handle. The product …
The Isomer Distribution In The Sulfonation Of Iodobenzene, Joseph A. Knight
The Isomer Distribution In The Sulfonation Of Iodobenzene, Joseph A. Knight
Theses and Dissertations
Using the isotope dilution technique, the distribution of isomers was determined when iodobenzene was sulfonated with sulfur trioxide in liquid sulfur dioxide. The active isotope was S^35. Before this distribution could be established, it was necessary to prepare the pure isomers of iodobenzenesulfonic acid. These were prepared by diazotization of the corresponding aminobenzenesulfonic acids. Since o-aminobenzenesulfonic acid was not readily available, it was necessary that it be synthesized before the diazo reactions could be carried out. Considerable work has been done on the development of a method whereby the bromobenzenesulfonic acids could be synthesized and obtained in pure form. Some …
The Dehydrocyclization Of Normal Heptane To Toluene With Supported Rhenium, Platinum And Molybdenum Catalysts, Robert R. Beishline
The Dehydrocyclization Of Normal Heptane To Toluene With Supported Rhenium, Platinum And Molybdenum Catalysts, Robert R. Beishline
Theses and Dissertations
The dehydrocyclization activity of supported platinum, molybdenum and rhenium catalysts was studied by determining the toluene yield from n-heptane as a function of temperature and metal concentration in the catalyst. The support was 100 to 200 mesh alumina. Metal concentrations of 0.01% to 1.0% platinum, 0.1% to 2.0% molybdenum and 0.1% to 2.5% rhenium were studied in the temperature range from 500° to 600° C. Platinum was shown to be superior to both molybdenum and rhenium at all temperatures and metal concentrations investigated. The rhenium data were somewhat erratic, but showed rhenium to be a poor dehydrocyclization catalyst. The apparatus, …
Thermal Reaction Of Hydrogen And Oxygen In Small Bore Tubes, Shib Charan Chattoraj
Thermal Reaction Of Hydrogen And Oxygen In Small Bore Tubes, Shib Charan Chattoraj
Theses and Dissertations
The thermal reaction of hydrogen and oxygen has been investigated from the standpoint of the important intermediate hydrogen peroxide in the region between 620-720 degrees centigrade in small bore Pyrex and steel tubes. The minimum explosion-temperatures with different flow rates and compositions of the mixture have been determined. They have been found to vary with the composition and flow rate of the mixture. The minimum explosion temperature is also found to vary with the condition of the reaction tube surface. The yield of hydrogen peroxide has been determined as a function of temperature, contact time, composition of feed stream, and …
The Instability Constant Of The Cobaltous Citrate Complex Ion Using Cobalt-⁶⁰ As A Tracer, Lee T. Cox
The Instability Constant Of The Cobaltous Citrate Complex Ion Using Cobalt-⁶⁰ As A Tracer, Lee T. Cox
Theses and Dissertations
The instability constant of a substance shows the tendency of a substance to dissociate into simple ions. The stability of the substance can be related to stabilities of other substances through the instability constant. Schubert gives a method for the determination of the instability constant which involves measurements of the adsorption of a radiotracer cation on a cation exchange resin. Two different types of resin were employed in this research. It was found that with a resin containing carboxylic acid exchange groups the adsorption of the cobaltous ion changed rapidly with pH but with a resin containing nuclear sulfonic acid …
A Correlation Of The Catalytic Activity Of Various Mixtures Of Rhenium And Molybdenum Sulfides In Liquid-Phase Hydrogenation Of Certain Reducible Organic Groups, Li-Chen Hsu
Theses and Dissertations
The promoter action of mixtures of catalysts has been reported in literature to be valuable in industries. Whether mixtures of rhenium and molybdenum sulfides would have promoter actions in the hydrogenations of certain reducible organic groups was the main object of this research. Mixtures of rhenium and molybdenum sulfides of various compositions were prepared by three different methods, i.e., (a) by saturating perrhenate and molybdate with hydrogen sulfide in hydrochloric acid solutions, (b) in ammonium hydroxide solutions followed by acidification, and (c) by treating perrhenate and molybdate with thiosulfate in dilute sulfuric acids followed by extraction with toluene to remove …
Calorimetric Heats Of Mixing Of Some Nonelectrolytic Binary And Ternary Solutions, James Bevan Ott
Calorimetric Heats Of Mixing Of Some Nonelectrolytic Binary And Ternary Solutions, James Bevan Ott
Theses and Dissertations
The heat of mixing of nonelectrolytic liquids is important in predicting the type of molecular interactions which exist in solutions of nonelectrolyted. The problem was to construct a calorimeter in which these heats of mixing could be measured accurately. Once constructed, the calorimeter was used to measure the heats of mixing of some binary and a ternary solutions. The systems chosen for study were the three liquid pairs formed between benzane, carbon tetrachloride, and cyclohexane, and the ternary mixture of the three. The results of the experimentation are summarized by the following equations. (1) H_12^M = X_1x_2 [103.2 + 13.1(x_1 …
Some Aspects Of The Chemistry Of The Hydroquinoxalines Unsubstituted On The Nitrogen Atoms, Evan L. Allred
Some Aspects Of The Chemistry Of The Hydroquinoxalines Unsubstituted On The Nitrogen Atoms, Evan L. Allred
Theses and Dissertations
A search of the literature revealed that almost nothing is known concerning the class of compounds known as decahydroquinoxalines. Since this posed a problem involving a search for a systematic synthetic method of general application as well as a method for establishing the characteristic class and individual properties, a research project under the guidance of Dr. H. Smith Broadbent was initiated. Of particular interest aside from matters of purely chemical interest was the recognition that the hydroquinoxalines possess obvious structural similarities with atropine and other well-known drugs which have valuable application as hypotensive agents, analgesics, spasmolytic agents, parasympathetic depressants, antihistaminics, …
Acidic Properties Of Clay Minerals And Alumina, Kenneth H. Anderson
Acidic Properties Of Clay Minerals And Alumina, Kenneth H. Anderson
Theses and Dissertations
Acidic properties of dialyzed alumina and representative clay minerals were studied by performing titrations with various bases. For the first group of experiments the titrations were made in a water system using KOH and NaOH. For this study in a water system the experimental data includes individual cationic activities as well as pH values. Adsorption of the cations was adequately described over a pH range of 5-11 by the equation 1-θ/θ ⋅ aNa+ ⋅ aOH- = 1/K'3 [aOH- + KW/K'2 + 1/K'1], in which θ represents the fraction of the total sites that have reacted. Thermodynamic constants K'3 and K0= …
The Effect Of Ferrous And Ferric Ions On The Conversion Of Malate To Pyruvate By A Cell Free Extract Of Pigeon Liver, Keith Erwin Richardson
The Effect Of Ferrous And Ferric Ions On The Conversion Of Malate To Pyruvate By A Cell Free Extract Of Pigeon Liver, Keith Erwin Richardson
Theses and Dissertations
Recent investigations on the crude pigeon liver extracts have shown the presence of an enzyme which catalyzes the oxidative decarboxylation of malate to pyruvate and carbon dioxide. The name malic enzyme has been given to this enzyme to distinguish it from malic dehydrogenase. Under aerobic conditions the addition of ferrous sulfate resulted in inhibition of the action of malic enzyme. Subsequent investigation showed that the inhibition obaerved was not due to ferrous ions, but due to ferric ions which were contaminating the ferrous sulfate. It was also shown that under aerobic conditions ferrous ions were rapidly oxidized to ferric ions. …
Colorimetric Determination Of Rhenium In Ores, Clair Winston Rogers
Colorimetric Determination Of Rhenium In Ores, Clair Winston Rogers
Theses and Dissertations
The problem of colorimetrically determining rhenium in the presence of molybdenum, copper, iron, sulphur, and rare earth elements with the use of dimethylglyoxime as the complexing compound was accomplished by the method reported here-in. The interfering elements were eliminated either as gaseous oxides and sulfides or were precipitated from a highly basic solution by means of a strong alkaline fusion of equal weights of sodium hydroxide and sodium peroxide, and the ore sample containing rhenium. The fusion product was dissolved in water, the solution boiled with a slight excess of sodium peroxide, and the hydroxide of all the interfering ions …
Thermodynamic Properties Of Water Adsorbed On Kaolinite, S. John Bennett
Thermodynamic Properties Of Water Adsorbed On Kaolinite, S. John Bennett
Theses and Dissertations
The object of the work presented in this thesis was to obtain quantitative values of the thermodynamic changes in water upon adsorption by kaolinite. Two methode were used. The first was a determination of the differential heat content and entropy of adsorption. The second method included a thermodynamic evaluation of the B.E.T. "c" constant expressed in terms of the Gibbs standard free energy of adsorption. The experimental data gave satisfactory results in determining the differential and standard thermodynamic functions or free energy, entropy, and heat content of adsorption. The adsorption of water on kaolinite appears to be a van der …
Evaluations Of Two Proposed Mechanisms Of Cation Adsorption By Silicate Minerals, Norman D. Larsen
Evaluations Of Two Proposed Mechanisms Of Cation Adsorption By Silicate Minerals, Norman D. Larsen
Theses and Dissertations
Previous work done at the Brigham Young University by Andelin^1, Roberts^2, and Olsen^3, has established the mechanism by which xanthate collectors are adsorbed on molybdenite ores to produce the hydrophobic surfaces necessary for flotation. This thesis is an attempt to better understand the mechanism by which the silicate minerals, which are found in conjunction with the ores, become hydrophyllic and as a result are not floated when in contact with air bubbles. It has been previously established that silicate minerals do adsorb cations on their surfaces^4. The present study has been undertaken to more fully understand the mechanism by which …
Mechanism Of Adsorption Of Cations By Silicate Minerals, Milton Glen Armstrong
Mechanism Of Adsorption Of Cations By Silicate Minerals, Milton Glen Armstrong
Theses and Dissertations
Adsorption of cations by clays has been a subject of investigation for many years. Many proposals have been advanced to explain this process of adsorption. Two proposals have been prominent in recent years. The Marshall "charged lattice" theory attributes adsorption of cations by clays to an electrostatic attration of the clay particles for cations. This charge on the clay particles is attributed to various isomorphic substitutions in the lattice of the clay which result in an unbalanced charge on the particle. This isomorphic substitution can take place either in the silicon-oxygen tetrahedra of the silicate structure or with the aluminum …
Collector-Depressant Equilibria In The Selective Flotation Of Sulfide Ores, Heber Ross Olson
Collector-Depressant Equilibria In The Selective Flotation Of Sulfide Ores, Heber Ross Olson
Theses and Dissertations
This dissertation presents the results of a collector - depressant equilibria study of the flotation systems potassium n-amyl xanthate - sodium cyanide - molybdenite and ethyl zanthate sodium sulfide - molybdenite and the study of conditions necessary for the selective flotation of covellite, tetra-hedrite, bornite, chalcopyrite, molybdenite, marcasite and pyrite in the system ethyl xanthate and sodium cyanide; the conditions necessary for the selective flotation of pyrite, covellite, bornite, galena, chalcopyrite, active sphalerite, and molybdenite in the system potassium ethyl xanthate and sodium sulfide; the conditions necessary for the selective flotation of molybdenite and pyrite in the system of potassium …
Ultraviolet Absorption Spectra Of Quinoxaline And Some Of Its Derivatives, Fred Dale Huillet
Ultraviolet Absorption Spectra Of Quinoxaline And Some Of Its Derivatives, Fred Dale Huillet
Theses and Dissertations
A long term research program into the chemistry of quinoxalines has been instituted at Brigham Young University with the aim of preparing the vinylquinoxalines so that their 1,4-addition reactions might be studied. The literature of quinoxaline chemistry has been thoroughly reviewed and assembled. Methods of preparing 2-methyl- and 2,3-dimethylquinoxaline have been studied and improved but all attempts to prepare the vinylquinoxalines have been unsuccessful. In the course of these attempts several compounds of unknown structure were prepared. The purpose of this investigation is to study the spectra of various known quinoxaline derivatives and to attempt to identify the unknowns by …
Thermodynamic Properties Of Water Absorbed On Silica, Conrad V. Hatch
Thermodynamic Properties Of Water Absorbed On Silica, Conrad V. Hatch
Theses and Dissertations
The object of the work presented in this thesis was to obtain quantitative values of the thermodynamic changes in water upon adsorption by silica. Two methods were used. The first was a determination of the differential entropy and heat of adsorption independent of any theory of adsorption. The second method included a new interpretation of the "c" constant of the Brunauer, Emmett, and Teller Theory in which c was expressed in terms of the standard free energy of adsorption. The experimental data gave satisfactory results in determining the differential heat and entropy of adsorption. The results obtained in determining the …
Collector-Depressant Equilibria For The Flotation System Potassium Ethyl Xanthate-Potassium Cyanide-Molybdenite, Connell Bolton Roberts
Collector-Depressant Equilibria For The Flotation System Potassium Ethyl Xanthate-Potassium Cyanide-Molybdenite, Connell Bolton Roberts
Theses and Dissertations
This dissertation involves a study of the collector-depressant equilibria of the flotation system potassium ethyl xanthate-potassium cyanide-molybdenite, based upon mineral-air bubble contact measurements made by a modified captive bubble technique. The Cook theory of single site free acid adsorption is used to interpret the data. The standard free energies of adsorption of ethyl xanthic acid and hydrocyanic acid on molybdenite are calculated.
Collector-Depressant Equilibria In The Flotation Of Molybdenite, Robert Létrenne Andelin
Collector-Depressant Equilibria In The Flotation Of Molybdenite, Robert Létrenne Andelin
Theses and Dissertations
This dissertation presents the results of research on the flotation system potassium n-amyl xanthate - sodium sulfide - molybdenite. The purposes of the research were (1) to determine the theoretical collector-depressant equilibria conditions of this system necessary for the flotation or depression of molybdenite, (2) to ascertain the mechanism of adsorption or the collector potassium n-amyl xanthate and the depressant sodium sulfide on molybdenite, and (3) to calculate the standard free energy of adsorption on molybdenite of the collector and depressant in this system. To accomplish these purposes it was necessary to develop a satisfactory experimental method for the controlled …