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Articles 4441 - 4470 of 4499

Full-Text Articles in Physical Chemistry

Analysis Of The A3(X3)3 Nuclear Spin System And -Electron Coupled Hyperfine Splitting Constants In Aromatic Hydrocarbons, Juana Acrivos Jan 1961

Analysis Of The A3(X3)3 Nuclear Spin System And -Electron Coupled Hyperfine Splitting Constants In Aromatic Hydrocarbons, Juana Acrivos

Faculty Publications, Chemistry

The nuclear spin functions for the A3(X3)3 system have been developed and used to analyse the NMR spectra of (CH3)3C6H3 and (CF3)3C6H3. The π-electron coupled hyperfine splitting constants, obtained from the Ramsey theory with simple Hückel M.O.'s for benzene and without the assumption of an average energy of excitation for the virtual processes which give rise to the coupling, are in agreement with the hyperfine constants observed between the methyl groups and the ring protons in the above compounds.

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The Dilute Solution Chemistry Of Antimony, Kent H. Jones Jun 1960

The Dilute Solution Chemistry Of Antimony, Kent H. Jones

Chemistry and Chemical Biology ETDs

Investigation of the chemistry of the elements by conventional methods is generally limited to concentrations on the order of 10-5 M or higher. The discovery of radio-activity opened new fields in chemistry among which is the obtaining of information concerning chemical behavior of elements at very low concentrations. For many years after the initial discovery of radioactivity in 1896 by Becquerel, the study of low-concentration chemistry was limited to about ten naturally occurring radioactive elements. A renewed interest in this field was generated after 1934 when it was discovered by Curie and Joliot that radioactive elements could be artificially …

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A Study Of The Kinetics Of The Oxidation Of Uranium(Iv) By Cerium(Iv), Floyd Beatty Baker Mar 1960

A Study Of The Kinetics Of The Oxidation Of Uranium(Iv) By Cerium(Iv), Floyd Beatty Baker

Chemistry and Chemical Biology ETDs

The kinetics of a number of oxidation-reduction reactions and exchange reactions involving cations of the transition and inner transition elements have been extensively reviewed by T. W. Newton and S. W. Rabideau. These workers represent the formation of the activated complex by an equation which includes only the principal species in solution as reactants.

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Spectroscopic Studies Of Metal-Cyanide Complexes: Part 1: Infrared And Visible Absorption Studies Of Cyanide Complexes Of Ni(Ii) In Aqueous Solution, Part 2: An Analysis Of The Infrared Vibrational Spectra Of The Tetracyanonickelate(Ii) Ion In The Solid State, Roy L. Mccullough Dec 1959

Spectroscopic Studies Of Metal-Cyanide Complexes: Part 1: Infrared And Visible Absorption Studies Of Cyanide Complexes Of Ni(Ii) In Aqueous Solution, Part 2: An Analysis Of The Infrared Vibrational Spectra Of The Tetracyanonickelate(Ii) Ion In The Solid State, Roy L. Mccullough

Chemistry and Chemical Biology ETDs

In this work, further evidence has been collected establishing the existence of a new ionic species in solutions of sodium tetracyanonickelate(II) and sodium cyanide. Contrary to the literature, however, this work shows that the species is [Ni(CN)5]-3 rather than [Ni(CN)6]-4.

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Liquid Scintillators. Some Aryl Substituted Phenanthrenes And Dihydrophenanthrenes, And Related P-Terphenyls And P-Quaterphenyls, Stephen Paul Birkeland May 1959

Liquid Scintillators. Some Aryl Substituted Phenanthrenes And Dihydrophenanthrenes, And Related P-Terphenyls And P-Quaterphenyls, Stephen Paul Birkeland

Chemistry and Chemical Biology ETDs

With the advent of good commercially available photomultiplier tubes, scintillation counters have become increasingly popular for laboratory use. Although there are a number of materials such as ionic crystals, covalent crystals, plastics, and liquid organic solutions, which are used in scintillation counters, liquid organic solutions offer distinct advantages. Because the organic solutes used in liquid scintillation systems have decay times of the order of 10-8 second, systems with resolving times of the order of 5x10-10 second may be obtained. This represents an improvement by a factor of 104 over gas counters and 102 over scintillation systems …

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A Spectrophotometric Study Of The Analytical Chemistry Of Vanadium, Kenton E. Bentley Nov 1958

A Spectrophotometric Study Of The Analytical Chemistry Of Vanadium, Kenton E. Bentley

Chemistry and Chemical Biology ETDs

Vanadium is most frequently encountered in analytical chemistry in the volumetric determination of vanadium by oxidation-reduction titration. Vanadium is rarely determined gravimetrically and finds little use as a reagent in gravimetric analysis. The simple ionic forms of the valence states of vanadium and the colors of acidic, aqueous solutions of these ions, as reported in the literature, are listed in Table 1. There is some confusion in the nomenclature of the ionic forms; that given in Table 1 is by analogy to chromium.

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The Synthesis Of Some Triazole Derivatives, John M. Collier Nov 1958

The Synthesis Of Some Triazole Derivatives, John M. Collier

Chemistry and Chemical Biology ETDs

The triazoles have been known since the late 1800's when von Pechmann discovered the ring system during the course of his work with osazones. He first assigned the name "osotriazone" to the parent ring; this was later changed to "osotriazole", a name which is still retained for certain derivatives obtained from the sugar osazones.

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The Synthesis Of Some Fluorine Derivatives As Potential Scintillation Solutes, Martin Dennis Barnett Oct 1958

The Synthesis Of Some Fluorine Derivatives As Potential Scintillation Solutes, Martin Dennis Barnett

Chemistry and Chemical Biology ETDs

In connection with work being carried out, in part, by the Biomedical Research Group, Los Alamos Scientific Laboratory, on the evaluation of organic compounds as solutes in liquid scintillation detector systems, it seemed of interest to investigate the liquid scintillation properties of fluorine analogues of p-terphenyl and p-quaterphenyl. These compounds have been shown to possess remarkable scintillation properties; however, the use of p-quaterphenyl has been severely curtailed by its low solubility in toluene. Accordingly, the synthesis of a number of 2- and 2,7-substituted fluorines was carried out in an effort to obtain a more soluble, completely conjugated aromatic system and …

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Thermodynamic Properties Of The System Pucl3-Kcl, Robert Benz Aug 1958

Thermodynamic Properties Of The System Pucl3-Kcl, Robert Benz

Chemistry and Chemical Biology ETDs

It is a general experimental result that as the temperature of a chemical system is increased the thermodynamic parameters of state become more important while the diffusion controlled and other activation type parameters become less important in controlling the net chemical reaction. The growing intereats in chemical processing of plutonium materials at elevated temperatures has emphasied the importance of an accurate knowledge of the thermodynamic data tor plutonium compounds as an aid to the prediction and the study of possible economically feasible processes.

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Synthesis Of 4, 7-Disubstituted Derivatives Of Imidazo-[4, 5-D]-Pyridazine And Related Compounds, William Seese Jul 1958

Synthesis Of 4, 7-Disubstituted Derivatives Of Imidazo-[4, 5-D]-Pyridazine And Related Compounds, William Seese

Chemistry and Chemical Biology ETDs

The antitumor activity of 8-azaguanine (5-amino-7-hydroxy-v-triasolo([d] pyrimidine) (A) prompted the preparation of the imidazo-[4, 5-d] pyridazine ring system (B). In this ring the two nitrogen atoms are adjacent in the six-membered ring with the five-membered imidazole ring remaining the same as in the parent purine ring (C).

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Some Aspects Of The Non-Aqueous Chemistry Of The Uranium Chlorides, Richard E. Panzer Jul 1958

Some Aspects Of The Non-Aqueous Chemistry Of The Uranium Chlorides, Richard E. Panzer

Chemistry and Chemical Biology ETDs

Uranium, discovered by Klaproth in 1789, has been the object of greatly intensified chemical and physical studies since the establishment of the Manhattan Project. An event such as the discovery of the hexachloride of uranium in 1943 points up the relatively unknown status of the chemistry of this element at a fairly recent date. It is not, therefore, surprising that the chemistry of many compounds of greater complexity than the hexachloride had not been investigated. However, with the search intensified for methods of separation of the naturally occurring isotopes for subsequent use in nuclear weapons and reactors, the years since …

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The Magnesium-Hydrogen System, J. Frederick Stampfer Jr. Jun 1958

The Magnesium-Hydrogen System, J. Frederick Stampfer Jr.

Chemistry and Chemical Biology ETDs

The motivating factor for this investigation of the magnesium-hydrogen system was the recent interest in the hydride of beryllium. Although beryllium hydride has been prepared by the pyrolysis of di-t-butylberyllium, no evidence for the direct union of beryllium and hydrogen has been reported. It was thought that an examination of the reaction between magnesium and hydrogen and determination of the thermodynamic relations involved might have a bearing on this phenomenon. Also, the properties of magnesium hydride are interesting from an over-all periodic table viewpoint. The hydrides of beryllium and magnesium are usually considered to be intermediary between the saline, or …

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The Extraction Of Scandium, Yttrium, And Lanthanum Using Various Monoalkyl Orthophosphoric Acids, Clarence Gerald Warren May 1958

The Extraction Of Scandium, Yttrium, And Lanthanum Using Various Monoalkyl Orthophosphoric Acids, Clarence Gerald Warren

Chemistry and Chemical Biology ETDs

The separation of lanthanum, yttrium, and the rare earth elements from their ores has been a challenge to the chemist for many years. The similarity in chemical properties has made their separation a problem of extraordinary difficulty. Fractional crystallization has been the classical method utilized in the past, although individual elements have been isolated by oxidation or reduction to other than the tripositive oxidation state (1). Recently ion exchange and solvent extraction methods have become more important as a means of separation of these elements. Both of these techniques depend upon fractional differences in the distribution of compounds or ions …

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Absorption Of Antimony(Iii) And Indium From Anhydrous Acetic Acid By Ion Exchange Resins, Robert Tor Lofberg May 1958

Absorption Of Antimony(Iii) And Indium From Anhydrous Acetic Acid By Ion Exchange Resins, Robert Tor Lofberg

Chemistry and Chemical Biology ETDs

Organic ion exchange resins are a comparatively recent development. In 1935 Adams and Holmes prepared the first ion exchange resin by polymerizing polyhydric phenols with formaldehyde. The condensation product exhibited definite reversible cation exchange properties. The success of this experiment led them to the development of the first anion exchange resin which was prepared by the polymerization of phenylenediamine with formaldehyde. The publication of these experiments inspired many similar investigations leading directly to the manufacture of the numerous ion exchange resins now commercially available.

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The Synthesis Of Some Methyl Substituted 3,4-Benzpyrenes, Jules L. Adelfang Oct 1957

The Synthesis Of Some Methyl Substituted 3,4-Benzpyrenes, Jules L. Adelfang

Chemistry and Chemical Biology ETDs

3,4-Benzpyrene (I), a highly carcinogenic hydrocarbon was first isolated from coal tar in 1933 by Cook, Hewett, and Hieger. Interest in the relationship of structure to carcinogenic activity and correlation of physical properties with carcinogenic potency led to the synthesis of several monomethyl 3,4-benzpyrenes during the decade following the isolation of the parent hydrocarbon. Detailed reviews concerned with the various phases of this research have been prepared. Recently the synthesis of the 1-^2, 7-^3, 8-^(2,5), and 10-^4 methyl-3,4-benzpyrenes completed the series of reported monomethyl derivaives.

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The Chemical Behavior Of Iodine At Tracer Concentrations, Henry Morris Eiland Jun 1957

The Chemical Behavior Of Iodine At Tracer Concentrations, Henry Morris Eiland

Chemistry and Chemical Biology ETDs

Radiochemistry was introduced as a separate branch of chemistry by Pierre and Marie Curie in 1898. The first radiochemical process consisted of the separation and identification of the new element Polonium from the uranium ores pitchblende and chalcalite. It is significant that this process involved an amount of material so small that it could be detected only by its intense radioactivity. In the last half-century radiochemistry has developed into a field of ever increasing diversification.

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A Study Of The Density And Molecular Species Of Polonium And Tellurium Vapor, Angelo L. Giorgi May 1957

A Study Of The Density And Molecular Species Of Polonium And Tellurium Vapor, Angelo L. Giorgi

Chemistry and Chemical Biology ETDs

The purpose of this investigation was to determine the nature of the species of polonium and tellurium in equilibrium in the vapor phase at temperatures ranging from 422 degrees to 1013 degrees C. for polonium and from 512 degrees to 880 degrees C. for tellurium. Such information was based on measurements of the variation of vapor pressure and vapor density with temperature. The results of this investigation suggest that both polonium and tellurium exist as diatomic molecules in the vapor phase over the aforementioned temperature ranges.

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Studies Of The Chemistry Of Systems Involving Water, Hydrogen Peroxide And Plutonium (Iv) Nitrate In Tri-N-Butyl Phosphate, Lawrence J. Mullins Jr. May 1957

Studies Of The Chemistry Of Systems Involving Water, Hydrogen Peroxide And Plutonium (Iv) Nitrate In Tri-N-Butyl Phosphate, Lawrence J. Mullins Jr.

Chemistry and Chemical Biology ETDs

The reaction of tri-n-butyl phosphate (TBP), with water and hydrogen peroxide is studied by means of distribution experiments. The solubility of water in TBP-hexane, at low TBP concentrations, is consistent with the premise that H2O•TBP is the principal solvate species formed at low hydrogen peroxide concentrations. The distribution data at high hydrogen peroxide concentrations indicate that another species such as H2O2•TBP is also present. The reaction of hydrogen peroxide with plutonium(IV) nitrate in TBP is studied by a spectrophotometric method. A complex is formed which contains one plutonium atom and two peroxy-oxygen atoms. The …

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A Radiochemical Investigation Of Short-Lived Selenium And Bromine Fission Products, James Edward Sattizahn Jr. May 1957

A Radiochemical Investigation Of Short-Lived Selenium And Bromine Fission Products, James Edward Sattizahn Jr.

Chemistry and Chemical Biology ETDs

From a sample of uranium bombarded with neutrons, Hahn and Strassmann, in 1939, separated four radioactive products which followed alkaline earth chemistry and were therefore tentatively attributed to isotope of radium. Each of these products decayed to a daughter activity which could be precipitated along with lanthanum; the daughter activities were then assumed to be isotopes of actinium. Subsequently, by accepted methods of fractional crystallization and precipitation, the "radium" and "actinium" isotopes were identified unequivocally as isotopes of barium and lanthanum, respectively. Within a relatively short time there were found more such radioactive products, which were identified as isotopes of …

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Behavior Of Indium At Tracer Concentrations, Katheryn L. Lawson May 1957

Behavior Of Indium At Tracer Concentrations, Katheryn L. Lawson

Chemistry and Chemical Biology ETDs

The increase in number and availability of radioisotopes that can be produced in the carrier-free state has offered practical means of investigating the chemical behavior of substances at extremely low concentrations. The working region of concentrations, which may extend to less than 10-14 molar, is generally fixed only by the half-life of the radio-element and the nature of the radiation.

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The Exchange Of Chlorine Between Hydrogen Chloride And Acetyl Chloride In The Vapor Phase, Warren J. Niell Apr 1957

The Exchange Of Chlorine Between Hydrogen Chloride And Acetyl Chloride In The Vapor Phase, Warren J. Niell

Chemistry and Chemical Biology ETDs

The aim of chemical kinetics is to predict the rates of chemical reactions, to determine the factors influencing the reaction rate, and to postulate a suitable reaction mechanism.

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The Chemical Effects Of Gamma Radiation On Halogenated Methanes, Clifford G. Shultz Feb 1957

The Chemical Effects Of Gamma Radiation On Halogenated Methanes, Clifford G. Shultz

Chemistry and Chemical Biology ETDs

The fundamental processes of radiation chemistry and photochemistry are quite parallel, and any consideration of one must include the theory of the other as well. Probably the first work done in photochemistry was that of Stephen Hales on photosynthesis, between 1677 and 1721. This was followed by descriptions of the action of light on silver salts by Schultz, Beccarius, and Scheele. The latter also demonstrated that the action of light on silver chloride varied with the waveleneth of the light. Grotthus, in 1817, stated the first law of photochemistry: Only that light which is absorbed can give rise to a …

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The Synthesis Of 7-Methyl-3,4-Benzpyrene, 6,7-Dimethyl-3,4-Benzpyrene, 10-Methyl-3,4-Benzpyrene And 7,10-Dimethyl-3,4-Benzpyrene, Joseph Leonard Comp Jr. Dec 1956

The Synthesis Of 7-Methyl-3,4-Benzpyrene, 6,7-Dimethyl-3,4-Benzpyrene, 10-Methyl-3,4-Benzpyrene And 7,10-Dimethyl-3,4-Benzpyrene, Joseph Leonard Comp Jr.

Chemistry and Chemical Biology ETDs

Interest in carcinogenic compounds began to develop when a form of cancer was found occurring in chimney sweeps in 1775. Skin cancer was found among workers in tar industries in 1875, and in 1887 workers in cotton spinning industries were known to have cancer which was attributed to contact with lubricating oils. Girls who painted the luminous dials of watches contracted cancer from exposure to the radioactive paint, and men who worked with B-naphthylamine developed bladder cancer. Many other cases of occupational cancer were reported before a systematic study of carcinogenic substances was begun. Early attempts to produce cancer in …

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A Study Of Isotopic Exchange Between Potassium Iodide And Benzyl Iodide. Solvent Effects, Joseph A. Leary May 1956

A Study Of Isotopic Exchange Between Potassium Iodide And Benzyl Iodide. Solvent Effects, Joseph A. Leary

Chemistry and Chemical Biology ETDs

The kinetics of nucleophilic aliphatic substitution reactions has been studied by numerous investigators during the past fifteen years. Included in this type of reaction are well-known general reactions such us (1) the Finkelstein reaction, (2) the Menschutkin reaction, (3) the alcoholysis of alkyl halides, and (4) various isotopic exchange reactions.

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Coprecipitation Of The Transuranium Elements With The Rare Earths Coprecipitation Of Americium With Lanthanum Oxalate, John A. Hermann Jan 1956

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.

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The Synthesis Of 1-Methyl-3,4-Benzpyrene, 8-Methyl-3,4-Benzpyrene And 1,8-Dimethyl-3,4-Benzpyrene, William Carter Doyle Dec 1955

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.

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The Decomposition Of Solid Barium Nitrate By Gamma Rays, Lawrence E. Lamar May 1955

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.

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The Synthesis Of 2-Methyl-3, 4-Benzpyrene And 2, 8-Dimethyl-3, 4-Benzpyrene, James W. Patton Aug 1954

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).

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The Exchange Of Antimony Between Antimony Trichloride And Antimony Pentachloride In Carbon Tetrachloride Solution, Franklin Brett Barker Jun 1954

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 …

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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 Jan 1954

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.

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