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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

A Quantitative study of the effects produced by salts by salts of sodium, potassium, rubidium, and calcium on motor nerve of frog /

Greisheimer, Esther Maud, January 1900 (has links)
Thesis (Ph. D.)--University of Chicago, 1919. / Caption title. Reprinted from the American journal of physiology, Vol. 49, No. 4, September, 1919. Includes bibliographical references (p. 522).
92

Iron tannage,

Hou, Te-Pang, January 1921 (has links)
Thesis (Ph. D.)--Columbia university, 1921. / Vita. "Reprinted from Journal of American leather chemists association, February, March, April, May, 1921." Bibliography: p. 74-76. Also available in digital form on the Internet Archive Web site.
93

Design of poorly soluble drug salts : pharmaceutical chemical characterization of organic salts /

Parshad, Henrik. January 2003 (has links)
Ph.D.
94

Synthesis of substances related to rubrementinum salts

Thackray, David January 1961 (has links)
In 9152, the evidence available was still insufficient to decide between various structures proposed for the rubrementinium salts. The author has therefore attempted to gather further evidence. The evidence available in the literature is discussed in Part II, and the author's work in Parts III and IV of this thesis. The substances which the present author has termed rubremetinium salts have more than one name in the literature. Karrer uses the name “dehydroemetin”. Pyman, who discovered the salts, at first used “rubremetine”. It was later found, however, that the salts are quaternary, so Pyman applied to the quaternary ion the name “rubremetinium”. This name will be used throughout the present thesis.
95

The reduction of cupric salts in aqueous solutions by carbon monoxide.

Byerley, John Joseph January 1963 (has links)
The kinetics of the carbon monoxide reduction of Cu(II) to Cu(I) in aqueous solutions were studied at 120°C and carbon monoxide pressures up to 1360 atm. The reduction was followed spectrophoto-metrically in a high pressure titanium cell specifically developed for studying reactions between transition metal ions and gaseous reducing agents. The observed kinetics in acetate-buffered solutions yield a rate law of the form [ Formula omitted ] The rate law describes a reaction that occurs by two parallel paths, one of which is effectively independent of pressure and is accounted for by a stable carbon monoxide complex, described by Cu(CO)+. The pressure-dependent path contains both a pH-dependent and pH-independent reaction. The observed kinetics are consistent with the following mechanism which includes the insertion of a carbon monoxide molecule between a copper ion and a co-ordinated water molecule. [ Formulas omitted ] The effect of complexing was found to be quite minor. This was further verified by studies in sulphate and perchlorate solutions. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate
96

The reduction of cupric salts in aqueous solution by molecular hydrogen

Macgregor, Edwin Robert January 1956 (has links)
The thesis describes a kinetic study of the reactions between cupric salts and hydrogen in aqueous solution. The first part is concerned with the homogeneous activation of hydrogen in solution by cupric perchlorate, as evidenced by its catalytic effect on the reaction between dichromate and hydrogen. These studies, which were conducted on solutions of higher acidity than previously investigated, provide further support for the mechanism proposed for this reaction, i.e., Cu⁺⁺ + H₂[formula omitted] CuH⁺+ H⁺ CuH⁺ + Cu"⁺⁺" □(→┬(k₂) ) 2Cu⁺ + H⁺ 2Cu⁺ + substrate □(→┬fast ) 2Cu⁺⁺ + products and the corresponding rate equation: (d[H^2])/dt = (k^₁ [Cu^(++) ]^2 [H^2])/((k^(-1)/(k^2 [H^+ ] )+[Cu^(++)]) The second part deals with the thermodynamics and kinetics of the precipitation of metallic copper from aqueous solution by H₂. The reduction reactions were studied in both cupric perchlorate and cupric sulphate solutions and the effects of a number of variables on the reaction rate in both systems are compared. The rate, which was initially fast, decreased gradually until an apparent steady-state condition was approached. This behavior was common to both systems, although the rates were much higher and the. residual copper concentration lower in the sulphate system. This apparent steady-state is not predicted by thermodynamics and is considered to result from kinetic factors. The dependence of the reaction rate on a number of variables can be predicted from the mechanism Cu⁺⁺ + H₂[formula omitted]CuH^++H⁺ CuH⁺ + Cu⁺⁺□(→┬(K₂) ) 2Cu⁺ + H⁺+ + 2Cu² □(→┬fast ) Cu° + Cu⁺⁺ which corresponds to an overall reaction of Cu⁺⁺ + H₂ → Cu° + 2H⁺ Reasonably good quantitative agreement between the predicted and measured kinetic dependence on Cu⁺⁺, H⁺ and H₂ concentration suggests that the rate of reduction of cupric salts is determined by the homogeneous activation of H₂ by Cu⁺⁺+ or a cupric complex. Although the initial decrease in rate can be predicted by this mechanism, the apparent steady-state condition approached cannot be fully explained. The equilibrium constant for the reaction 2Cu⁺ ⇌ Cu⁺⁺ + Cu° was also determined experimentally at several temperatures and compared with calculated values. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate
97

A theoretical study of ammonia-salt mixtures in bulk solutions and interfacial regions

Perkyns, John Stephen January 1990 (has links)
Five models, ranging from a full molecular polar/polarizable model with C₃v symmetry, to the primitive model of ions in a dielectric continuum, have been used to study the properties of ammonia both as a pure liquid and as a solvent. Ammonia is modelled as a multipolar polaxizable hard sphere and ions as charged hard spheres. Using these models, in conduction with the Reference Hypernetted-chain integral equation theory, ammonia has been studied as a pure liquid, as a solvent near charged and uncharged surfaces, and in electrolyte solutions of finite concentration. The formalism of Kirkwood and Buff was used to obtain thermodynamic quantities of ionic solutions from calculated distribution functions. Structural, thermodynamic and. dielectric properties were calculated for pure ammonia and were compared with experiments where possible. Values for the dielectric constant and the configurational energy were found to compare favorably with experiment. Ammonia formed a relatively dense, highly structured layer within two solvent diameters of an uncharged surface. This structure was analyzed in terms of angular probability distributions of the molecular dipole vector and the NH-bond direction, and was found to be similar to that of frozen ammonia. The extreme asymmetry of solvation of unlike charges in ammonia was also investigated. Small cations were found to be more favorably solvated than small anions, but as the ion size was increased, the situation reversed. Estimates of the number of ion pairs in liquid ammonia and their effects on the behavior of mean molar activity coefficients were examined. Large differences between experimental activity coefficients and the Debye-Hückel hmiting law could not be explained by the usual ideas of ion pairing. It was found that the integral equation theories appear to have no solution between ionic concentrations of about 2 x 10⁻⁴M and 2 x 10⁻²M for either molecular or continuum models. Using rigorous stability criteria, this behavior was shown to be consistent with the onset of a phase change. It is proposed that such phase separation phenomena might explain the unusual behavior of the experimental activity coefficients. / Science, Faculty of / Chemistry, Department of / Graduate
98

Reduction mechanisms in fused salt-alloy systems

John, Thomas Grant January 1966 (has links)
Reactions between ions in LiCl-KCl eutectic melt and lead alloys have been studied kinetically between 370 and 450°C. Diffusion of the reducing ionic species across the salt-phase boundary layer was shown to be the rate controlling step for the reductions of Pb⁺⁺ , Cd⁺⁺ , Ag⁺ and In⁺⁺⁺ by lithium and of Cr⁺⁺⁺ by lead. Values of the salt-phase boundary layer thickness were estimated. Limited solubility of the reduced metal in the molten alloy resulted in metal deposition at the phase boundary during the reductions of Co⁺⁺, Cr⁺⁺⁺and Ti⁺⁺⁺by lithium. An apparent homogeneous reaction in the salt occurred during the reductions of Ni⁺⁺ and Pt⁺⁺ by lithium. The mechanisms have not been established but may involve solubility of either lithium or a Li-Pb intermetallic compound in the salt. The interfacial reactions were primarily electrochemical in nature, and never rate controlling. The diffusion coefficients of a number of ions in LiCl-KCl at 400 C were determined. The values showed that ionic diffusion in this eutectic was influenced primarily by the ionic charge of the diffusing species. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate
99

Synthesis of Diazonium (Perfluoroalkyl) Benzenesulfonylimide Zwitterions

Mei, Hua, Vanderveer, Don, Desmarteau, Darryl D. 01 January 2013 (has links)
The synthesis and properties of diazonium (perfluoroalkyl) benzenesulfonylimide (PFSI) zwitterions are described. The general procedures for the diazonium PFSI zwitterions involve three steps: (1) a coupling reaction, (2) a reduction reaction and (3) a diazotization reaction. These novel diazonium PFSI zwitterions represent a new versatile class of remarkably stable diazonium materials with potential for modification of carbon supports for electrodes in proton exchange membrane (PEM) fuel cells.
100

Synthesis of Diazonium (Perfluoroalkyl) Benzenesulfonylimide Zwitterions

Mei, Hua, Vanderveer, Don, Desmarteau, Darryl D. 01 January 2013 (has links)
The synthesis and properties of diazonium (perfluoroalkyl) benzenesulfonylimide (PFSI) zwitterions are described. The general procedures for the diazonium PFSI zwitterions involve three steps: (1) a coupling reaction, (2) a reduction reaction and (3) a diazotization reaction. These novel diazonium PFSI zwitterions represent a new versatile class of remarkably stable diazonium materials with potential for modification of carbon supports for electrodes in proton exchange membrane (PEM) fuel cells.

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