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Articles 151 - 180 of 186
Full-Text Articles in Physical Sciences and Mathematics
A Study Of Isotopic Exchange Between Potassium Iodide And Benzyl Iodide. Solvent Effects, Joseph A. Leary
A Study Of Isotopic Exchange Between Potassium Iodide And Benzyl Iodide. Solvent Effects, Joseph A. Leary
Chemistry and Chemical Biology ETDs
The kinetics of the isotopic exchange reaction between potassium iodide and benzyl iodide in alcoholic solution has been studied thoroughly by Stillson. It was reported that the reaction was much faster in ethanol-acetone mixtures than in absolute ethanol. However, it was not possible to determine whether this was due to acceleration of the reaction by acetone, or to inhibition by ethanol.
The purpose of this investigation was to elucidate further the effect of various solvents on the same exchange reaction. The isotopic exchange reaction between potassium iodide and p-nitrobenzyl iodide was also studied, because it had been investigated in alcoholic …
Coprecipitation Of The Transuranium Elements With The Rare Earths Coprecipitation Of Americium With Lanthanum Oxalate, John A. Hermann
Coprecipitation Of The Transuranium Elements With The Rare Earths Coprecipitation Of Americium With Lanthanum Oxalate, John A. Hermann
Chemistry and Chemical Biology ETDs
Coprecipitation is a process whereby a substance soluble by itself is "carried" with an insoluble crystalline precipitate. As used here, coprecipitation applies to the "carrying" of a tracer by a precipitate formed in the presence of the tracer. The phenomenon is important in analytical chemistry1, in the problem of impurities in precipitates; in radiochemistry2,3, in the separation of radioactive tracers originally present in very low concentrations; and in general, whenever a solid is separated from its mother liquid by precipitation.
The Synthesis Of 1-Methyl-3,4-Benzpyrene, 8-Methyl-3,4-Benzpyrene And 1,8-Dimethyl-3,4-Benzpyrene, William Carter Doyle
The Synthesis Of 1-Methyl-3,4-Benzpyrene, 8-Methyl-3,4-Benzpyrene And 1,8-Dimethyl-3,4-Benzpyrene, William Carter Doyle
Chemistry and Chemical Biology ETDs
The search for the carcinogenic factor present in crude oil tar fractions was begun around 1915. With the observation that the high-boiling, most carcinogenic fractions exhibited fluorescence spectra similar to those of many polycyclic aromatic hydrocarbons, several synthetic hydrocarbons were tested (1) on mice by skin painting techniques. Tumors were produced by 1,2,5,6-dibenzanthracene (I), 3'-methyl-1,2,5,6-dibenzanthracene (II) and 6-isopropyl-1,2-benzanthracene (III). One of the most widely used synthetic hydrocarbon carcinogens at the present is 1,2,5,6-dibenzanthracene.
The Decomposition Of Solid Barium Nitrate By Gamma Rays, Lawrence E. Lamar
The Decomposition Of Solid Barium Nitrate By Gamma Rays, Lawrence E. Lamar
Chemistry and Chemical Biology ETDs
Very little work has been done on the chemical effects produced during the irradiation of solid materials. Although some research has been reported concerning the action of ultraviolet light on solid nitrates, most of the information in the literature is based upon the use of nuclear radiations.
Two types of reaction mechanisms have been proposed by previous authors. The direct decomposition of the metal nitrate to give the nitrate and oxygen was concluded from measurements of optical absorption. The ionization of nitrate ion to yield mononitrogen trioxide which could disassociate after capture of an electron was also suggested. The mononitrogen …
The Synthesis Of 2-Methyl-3, 4-Benzpyrene And 2, 8-Dimethyl-3, 4-Benzpyrene., James W. Patton
The Synthesis Of 2-Methyl-3, 4-Benzpyrene And 2, 8-Dimethyl-3, 4-Benzpyrene., James W. Patton
Chemistry and Chemical Biology ETDs
In 1933 Cook, Hewett and Hieger (1) isolated a carcinogenic hydrocarbon from coal tar thought to be 3,4-benzpyrene (I).
The Exchange Of Antimony Between Antimony Trichloride And Antimony Pentachloride In Carbon Tetrachloride Solution, Franklin Brett Barker
The Exchange Of Antimony Between Antimony Trichloride And Antimony Pentachloride In Carbon Tetrachloride Solution, Franklin Brett Barker
Chemistry and Chemical Biology ETDs
In the investigation of any chemical reaction, the main points of interest are the conditions of equilibrium, the rate at which equilibrium is approached, and the mechanisms by which the reaction occurs. The first of these is determined by the standard free energy change, a thermodynamic quantity which depends only upon the initial and final states of the system. However, two reactions having the same value of the standard free energy change may approach equilibrium at radically different rates, one being practically instantaneous and the other almost infinitely slow. The field of chemical kinetics is concerned with the study of …
Exchange Reactions Of The Transuranium Elements Section 1. Am(Iii)-Am(V)-Am(Vi), Am(Iii)-Am(V), And Am(V)-Am(Vi), Thomas K. Keenan
Exchange Reactions Of The Transuranium Elements Section 1. Am(Iii)-Am(V)-Am(Vi), Am(Iii)-Am(V), And Am(V)-Am(Vi), Thomas K. Keenan
Chemistry and Chemical Biology ETDs
No exchange work prior to this dissertation has been reported on the Americium system. Neptunium exchange is presently being studied by J. C. Hindman and co-workers at the Argonne National Laboratory, but has not been completely reported. Study of uranium exchange, which is still in an unsatisfactory state, has been limited to the U(IV)-(VI) exchange.
The Synthesis Of 10-Methyl-3, 4-Benzpyrene And 8,10-Dimethyl-3, 4-Benzpyrene, Jules Adelfang
The Synthesis Of 10-Methyl-3, 4-Benzpyrene And 8,10-Dimethyl-3, 4-Benzpyrene, Jules Adelfang
Chemistry and Chemical Biology ETDs
In 1953 Cook, Hewett, and Rieger found a highly carcinogenic hydrocarbon in coal tar. By a variety of solvent extraction methods, fractional distillation, and crystallization several pure hydrocarbons were isolated from the crude pitch. Two new pentacyclic aromatic hydrocarbons were isolated and since only small quantities of them were available it was decided to ascertain their structures by synthesis instead of degradetive experiments. The hydrocarbon samples were obtained with great difficulty from two tons of crude pitch. The problem was simplified since ten of the possible fifteen pentacyclic hydrocarbons were known. From certain similarities of these hydrocarbons to perylene its …
An Investigation Of Some Changes In The Chemical Composition Of Arterial Tissue Which Correlate With The Development Of Arteriosclerosis, Richard Dee Strickland
An Investigation Of Some Changes In The Chemical Composition Of Arterial Tissue Which Correlate With The Development Of Arteriosclerosis, Richard Dee Strickland
Chemistry and Chemical Biology ETDs
Arteriosclerosis is one of the major health problems confronting people of middle and advanced age. The disorder, commonly called "hardening of the arteries", is a contributing factor in more deaths than any other ailment.
The profound alteration in the physical properties of arteries which comes about as a result of the sclerotic process suggests that equally important changes may take place in the chemical composition of the arterial tissue.
Studies In The Cinnoline Series, David B. Cox
Studies In The Cinnoline Series, David B. Cox
Chemistry and Chemical Biology ETDs
Recent work by Castle and Kruse (16) has partially elucidated the range of reactivity of the chlorine atom in the compounds 4-chlorocinnoline and 4-chloro-6,7-dimethoxycinnoline. Condensations between the chlorinated cinnolines and certain phenylacetonitriles were found to proceed readily; however, condensations with compounds of the malonic ester type were unsuccessful. It was found that hydrolysis of the condensation product obtained from 4-chlorocinnoline and phenylacetontrile by hot 60% sulfuric acid caused decarboxylation of the intermediate acid, the final product being 4-benzylcinnoline. This compound has a formal resemblance to the basic ring structure of papaverine.
Chelation Of The Rare Earth Elements As A Function Of Ph Using Thenoyltrifluoroacetone, Hugh James Bronaugh
Chelation Of The Rare Earth Elements As A Function Of Ph Using Thenoyltrifluoroacetone, Hugh James Bronaugh
Chemistry and Chemical Biology ETDs
The rare Earth elements, or lanthanides, having atomic numbers 57 through 71 occupy only one space in the periodic chart of the elements. These fifteen elements, which have extraordinarily similar chemical and physical properties, are placed in group three of the periodic table, between barium of group two and hafnium of group four. This series of elements has been the subject of extensive study in the past. The development of atomic energy has significantly increased the interest in the rare earths in the past ten years.
A Study Of The Kinetics And The Free Radicals Involved In The Low-Pressure, Vapor-Phase Pyrolysis Of Toluene, Robert E. Williams
A Study Of The Kinetics And The Free Radicals Involved In The Low-Pressure, Vapor-Phase Pyrolysis Of Toluene, Robert E. Williams
Chemistry and Chemical Biology ETDs
This research was undertaken to study the pyrolysis of toluene in the vapor phase.
Many pyrolytic reactions of toluene have been studied by others, but the difficulty of controlling the reactions and the complexity of the products have not allowed much successful application of the results. The present work was an endeavor to better understand the reaction mechanisms and the intermediates involved in pyrolysis.
Specifically, the problem was to study the discrepancies between the results reported by M. Szwarc and by Hein and Mesee.
The Separation Of Antimony 125 From Solutions Of Neutron Irradiated Tin Salts, Joseph D. Robinson
The Separation Of Antimony 125 From Solutions Of Neutron Irradiated Tin Salts, Joseph D. Robinson
Chemistry and Chemical Biology ETDs
Because of the importance of high specific activities of radioactive species considerable experimental work has been done on the preparation of "carrier-free" tracers. In surveying the literature on the preparation of carrier-free antimony only one method was found. The method reported involves the deuteron bombardment of tin; solution of the target in agua regia; addition of cadmium carrier; precipitation of the cadmium as the sulfide which carries antimony, using oxalate ion to complex the tin; solution to the sulfides of cadmium and antimony in concentrated hydrochloric acid; distillation of tin from cadmium and antimony contained in in perchloric acid with …
Polargraphic Measurement Of Reaction Rates Of Diazonium Salts, Gregory W. Daues
Polargraphic Measurement Of Reaction Rates Of Diazonium Salts, Gregory W. Daues
Chemistry and Chemical Biology ETDs
If a colorimetric method is used for following the reactions by tracing the increase in dye concentration, only reactions which form soluble dyes can be studied. Gasometric techniques are limited in that a sample must be removed from the reaction vessel and the diazonium salt decomposed by means of a catalyst in order to measure the liberated nitrogen. The latter method of analysis lends itself more readily to studies of the rate of decomposition of diazonium salts under various conditions, such as, the presence of ultra-violet light or exposure to high temperatures.
The Kinetics Of The Exchange Between Diiodotyrosine And Iodine, Alfred H. Zeltzmann
The Kinetics Of The Exchange Between Diiodotyrosine And Iodine, Alfred H. Zeltzmann
Chemistry and Chemical Biology ETDs
The rate of exchange of iodine with diiodotyrosine in squamous solution was studied as a function of the concentrations of both reactants, of the pH, and of the temperature. The concentration of diiodotyrosine was varied from 0.0000475 to 0.01251 moles per liter and that of the iodine from 0.0000103 to 0.000395 moles per liter. The upper limits of concentration studied were determined by the solubilities of both the iodine and diiodotyrosine. The ratio of concentration of diiodotyrosine to that of iodine was varied from 227 to 0.5. the temperature was varied from 25.1 degrees C to 42.1 degrees C, and …
A Study Of The Exchange Between P-Nitrobenzyl Iodide And Iodide Ion In Alcoholic Solutions., E. Lee Purlee
A Study Of The Exchange Between P-Nitrobenzyl Iodide And Iodide Ion In Alcoholic Solutions., E. Lee Purlee
Chemistry and Chemical Biology ETDs
The realm of this study embraces observation of the exchange of iodine and potassium iodide in absolute methanol, absolute ethanol and absolute n-propanol at temperatures of 30.9 °, 20.3 ° and 0.0 ° centigrade. The primary aims were to observe the effects of the p-nitro group upon the exchange rates in effects of the p-nitro group upon the exchange rates in the various solvents and to compare the results with those obtained for the benzyl iodide-iodide exchange.
Enrichment Of Tin Activity Through The Szilard-Chalmers Separation, Herta W. Spano
Enrichment Of Tin Activity Through The Szilard-Chalmers Separation, Herta W. Spano
Chemistry and Chemical Biology ETDs
It was the purpose of this investigation to utilize the Szilard-Chalmers reaction in order to prepare tin solutions of high specific activity.
Tetraphenyl tin was chosen for the target compound. It is a white, crystalline solid of excellent thermal stability. No data have been reported in the literature on the rate of exchange between inorganic forms of tin and tetraphenyl tin but it seemed highly probable that this exchange would be very slow. Tetraphenyl tin is soluble in various organic solvents but insoluble in water, and this suggested solvent extraction as a possible means of separation of the activated tin …
Derivatives Of M-Xylene, Henry J. Muller
Derivatives Of M-Xylene, Henry J. Muller
Chemistry and Chemical Biology ETDs
Since m-xylene of 95-98% purity has recently become available from petroleum, this is an appropriate time to prepare an examine its derivatives. Isophtalic and m-toluic acids can be prepared from the hydrocarbon. The purpose of this work was to prepare imidazolines from these acids
The Chemical Characteristics Of 8.0-Day I^131 Produced By The Beta Decay Of 25-Minute Te^131 In Organic Liquids, Francis J. Keneshea Jr.
The Chemical Characteristics Of 8.0-Day I^131 Produced By The Beta Decay Of 25-Minute Te^131 In Organic Liquids, Francis J. Keneshea Jr.
Chemistry and Chemical Biology ETDs
In 1934 Szilard and Chalmers found that a large fraction of the radioactive iodine produced in the thermal neutron irradiation of ethyl iodide could be extracted from the irradiated material. The procedure followed was to add a trace of carrier iodine to the irradiated liquid, extract the iodine with an aqueous solution of a reducing agent and precipitate the iodide as silver iodide. The silver iodide precipitate obtained in this manner contained a large fraction of the iodine activity (25-minute I128), at a high specific activity. Since ethyl iodide is not soluble in water and hence is not …
The Kinetics Of The Exchange Between Benzyl Iodide And Iodide Ion, Paul Stillson
The Kinetics Of The Exchange Between Benzyl Iodide And Iodide Ion, Paul Stillson
Chemistry and Chemical Biology ETDs
In the investigation to be described here, the exchange reaction was carried out in methyl alcohol, ethyl alcohol, and acetone-alcohol mixtures. Radioactive I131 was used as a tracer throughout the investigation. A mechanism was postulated for this reaction in each solvent and activation energies were determined.
The Kinetics Of The Exchange Between Sn(Ii) And Sn(Iv) In Absolute Alcohol, E. Gerald Meyer
The Kinetics Of The Exchange Between Sn(Ii) And Sn(Iv) In Absolute Alcohol, E. Gerald Meyer
Chemistry and Chemical Biology ETDs
In the present work use was made of the radiochemical exchange reaction to study the kinetics of the reaction
SnCl2 + Sn*Cl4 = Sn*Cl2 + SnCl4
in an absolute alcohol medium. A rate equation was established as a function of concentration and temperature, and some predictions were made regarding the mechanism.
Some Reactions Of 4-Chlorocinnoline, F. H. Kruse
Some Reactions Of 4-Chlorocinnoline, F. H. Kruse
Chemistry and Chemical Biology ETDs
This problem involves the preparation of 4-chlorocinnoline by the method of Borshe and Herbert and Busch and Rast,, and the study of further replacement reactions of the chlorine atom in the 4-position. The problem can be subdivided into two sections: (1) the preparation of the 4-cinnolyl Grignard reagent and the corresponding lithium compound and (2) the study of some condensation reactions of 4-chlorocinnoline.
An Analytical Study Of Berberine, W. Riley Mcgaughran
An Analytical Study Of Berberine, W. Riley Mcgaughran
Chemistry and Chemical Biology ETDs
Berberine, an alkaloid, has unique pharmacological properties as well as unusual chemical and physical characteristics. This compound has been used for many years as a remedy for eye diseases. In contrast to most alkaloids, berberine hydroxide is more soluble than its salts. Its chemical structure has been established, but a correlations of many of its properties and its structures has not been made.
The purpose of this work was to undertake an analytical study of berberine, hoping to collect data which would make possible the correlation of certain properties of the compound with its structure. The study was planned to …
A Study Of The Use Of The Dicyanatodipyridine (Ii) Complex For The Determination Of Cyanate, Jean Mcclelland
A Study Of The Use Of The Dicyanatodipyridine (Ii) Complex For The Determination Of Cyanate, Jean Mcclelland
Chemistry and Chemical Biology ETDs
Treadwell states in his text, Analytical Chemistry, Volume II, that "the only method for examining cyanates consists in determining the amount of carbon and nitrogen present by combustion." A review of the available literature shows that, although this is not literally true, a procedure for this quantitative determination of small amounts of cyanates in the presence of interfering substances is lacking.
A survey of the literature yielded few references for instrumental methods for the quantitative determination of cyanates. Ripan-Tilici published a method for the determination of cyanates poteniometrically, but attempts to duplicate her work have failed. Madame Tilici, in …
The Syntheses And Ultraviolet Absorption Spectra Of 2-Imidazolines, 2-Imidazolidones And Imidazolidines, Robert J. Ferm
The Syntheses And Ultraviolet Absorption Spectra Of 2-Imidazolines, 2-Imidazolidones And Imidazolidines, Robert J. Ferm
Chemistry and Chemical Biology ETDs
The first method used to prepare 2-imidazolines was through the reaction of aromatic aldehydes with ammonia. Amarin, which is known as 2,4,5-triphenyl-2-imidazoline, was the first compound reported to be prepared in this manner. This type of reaction has since been widely studied 2,3,4,5,6 in connection with the preparation of 2,4,5-triarylimidazolines. Furfural and ammonia have also been reported to react in a similar manner. Amarin has also been obtained from the reaction of a mixture of benzil, ammonia, and benzaldehyde.
The Preparation And Properties Of Aromatic Ditellurides, Roger Sanftner
The Preparation And Properties Of Aromatic Ditellurides, Roger Sanftner
Chemistry and Chemical Biology ETDs
All attempts to arrive at a conclusion as to the structure of the ditellurides by chemical means were unsuccessful. It was found that the ditelluride either failed to enter into reaction, or it reacted with the elimination of tellrium. It is thought, however, that a spectrophotometric analysis of the bromine addition would furnish some information concerning the ditelluride structure.
The Chelation Of Praseodymium As A Function Of Ph Using Thenolytrifluoroacetone, Thomas K. Keenan
The Chelation Of Praseodymium As A Function Of Ph Using Thenolytrifluoroacetone, Thomas K. Keenan
Chemistry and Chemical Biology ETDs
The rare earth elements, including elements 57 through 71, provide many diverse series of studies through their chemical reactions. In as much as these elements are all in Group III of the periodic table, they are markedly similar in their properties. The separation, insulation and purification of the various rare earths from one another has long been a problem of great interest to the chemist.
A Study Of The Intermediary Products Formed During The Life Of A Copper Cyanide Plating Bath, Matthew E. Carlisle
A Study Of The Intermediary Products Formed During The Life Of A Copper Cyanide Plating Bath, Matthew E. Carlisle
Chemistry and Chemical Biology ETDs
Four aims of a study of cyanide baths were:
1. To study the intermediate products formed during the operation of plating and stripping baths under various conditions.
2. To identify these intermediate products or complexes and to determine whether or not they caused the failure of the bath.
3. To consider the conditions that caused a bath to fail, and to be able thereby to increase the life of the bath.
4. To develop a fast, accurate method for controlling the baths, preferably by means of the cyanide content.
The Use Of Ethyl 4,4-Dimethyl-1-Isopropyl-2-Imidazolinyl-2-Acetate In The Synthesis Of Some 2-Imidazolines, Jacob Shapira
The Use Of Ethyl 4,4-Dimethyl-1-Isopropyl-2-Imidazolinyl-2-Acetate In The Synthesis Of Some 2-Imidazolines, Jacob Shapira
Chemistry and Chemical Biology ETDs
One equivalent of N-(2-aminoisobutyl)-isopropyl-amine (I) was allowed to react with diethyl malonate to produce ethyl 4,4-dimethyl-1-isopropyl-2-imidazolinyl-2-acetate (II) in various yields which depended mainly on the temperature, time allowed for the reaction, and the method of isolation from the reaction mixture.
A Study Of Magnesium Silicate As A Base Matrix Material For Fluorescent Materials, John D. Hopperton
A Study Of Magnesium Silicate As A Base Matrix Material For Fluorescent Materials, John D. Hopperton
Chemistry and Chemical Biology ETDs
The purpose of the work herein described and discussed was to study the phosphor system built upon magnesium silicate as a base matrix material.
The particular phase of this study undertaken was a comprehensive survey of the activator materials, and an exhaustive study of one or two of these activator materials.