Thesis (Ph. D.)--University of Virginia, 1928.

Inaug-diss.--Stockholm högskola. / Bibliography: p. 101-103.

Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Thesis (M.E.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (p. 108-112). Also available via the World Wide Web.

The reduction of osmium tetroxide by a series of alcohols was studied spectrophotometrically. The reaction was observed to occur in two steps, unlike previously reported studies on this reaction. The identities of both reactants and products were established via a range of techniques. Equilibrium and kinetic data were gathered and reaction models were evaluated using equilibrium and kinetic modelling software. The following complexation reaction model emerged that simulates both the equilibrium and kinetic data. Os(VIII) + RCH2OHOs(VI) + RCHO2 Os(VIII) + Os(VI)k+2k1Complexk-2 Conditional rate constants and equilibrium constants were generated. Rate constants for the alcohol reactions were correlated with the Taft σ* constant. The ρ* value obtained (-1.4) is consistent with a hydride transfer mechanism coupled with synchronous removal of the hydroxyl proton. The identity of the osmium(VIII)-osmium(VI) complex has been suggested. Thermodynamic parameters were also reported. The rate constants for benzyl alcohol and 2-chloroethanol deviated from those predicted by the Taft plot. An explanation of enhanced resonance effects is offered for benzyl alcohol and an alternative reaction mechanism, involving proton abstraction, is offered for 2-chloroethanol. The reaction of the oxidation products of alcohols, namely ketones, with osmium tetroxide produced rate constants that were, perhaps surprisingly, far larger than those of the alcohols. A reaction mechanism for the oxidation of the ketones is suggested, which involves the enolate ion as the reactive starting reagent.

A general algorithm for the computation of chemical equilibria in complex systems containing non-ideal solutions has been developed. The method is a G-minimization based on repeated linear and nonlinear programming steps. A computer program (THERIAK) based on this algorithm has been written and was used to solve a great variety of problems, ranging from a simple blast furnace calculation to liquid-liquid unmixing in a four component silicate melt. The computing times are in the magnitude of 1/2 to 2 seconds for each calculation. The method can also be used to test the consequences of thermodynamic models and data in systems of interest to many fields, including chemistry, geochemistry and metallurgy. Integrated powder diffraction intensities can be used to measure Mn-Mg and Fe-Mg site occupancies in olivines because of the difference in scattering factors between Mg and Mn or Fe. Theoretically calculated intensity ratios are subject to uncertainties from positional parameters (less than 3.5 % for peaks with a relative intensity greater than 25 %) and unknown charge distribution (up to 30 %). Several peak ratios are less subject to this last uncertainty and may be used to measure the site occupancies in olivines. 27 synthetic Fe-Mn-Mg olivines (800 °C, vacuum, with graphite) were investigated with Mossbauer spectroscopy and XRD intensity evaluation, producing occupancies accurate to approximately 0.03 per site. A thermodynamic speciation model represents the data very well. Preliminary Fe-Mn-Mg exchange experiments involving olivine and garnet place some limits on element distributions between these two minerals. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 1977 / Includes bibliographical references. / Ph. D. / Ph. D. Massachusetts Institute of Technology, Department of Chemistry

Thermodynamic equilibrium constants were obtained potentiometrically using a Beckman pH meter for metal-serine and metal-thioglycolloc acid complexes to study the thermodynamic properties of the complexes and the effect of dπ - dπ bonding on the equilibrium constants. The following calculations were made: 1. The stepwise dissociation of protons from serine at 10, 20, 30, and 40°C and the stepwise dissociation of protons from thioglycollic acid at 20, 30, and 40°C. 2. The thermodynamic formation constants for Zn(II), Cd(II), Hg(II), and Ag(I) with serine at 10, 20, 30, and 40°C and at two ionic strengths. 3. The thermodynamic formation constants for Zn(II), Cd(II), Hg(II), and In(III) with thioglycollic acid at 20 and 30°C and at two ionic strengths. 4. The entropy, enthalpy, and free energy change for each of the metal-serine complexes. The order of increaseing stability of log K_1 for the metal-serine systems was as follows: Hg(II) > > Zn(II) > Cd(II) > Ag(I), and for log K_2 the order: Hg(II) > > Zn(II) > Cd(II) ≈ Ag(I). The stability of the Hg(II)-serine was high becasue of the high electronegativity of Hg(II) and an abundance of 4f and 5d electrons that can be polarized by the ligand donor atoms. Values for log K_1 of Zn(II), Cd(II), and Ag(I) with serine decreased in the order of decreasing electronegativity of the metal ions. All log K_2 values were smaller than log K_1 values and followed the same order of stability as log K_1 with the exception of the Ag(I)-serine complex. Linear bonding is more stable for Ag(I) than any other spatial configuration. The second formation constant is this higher than the first because the second ligand completes this stable linear complex. In(III) precipitated as a hydroxide, making it impossible to measure a formation constant for In(II) with serine. The order of increasing stability of log K_1 for the metal-thiogly-colloc acid system was as follows: Hg(II) In(III) Cd(II) Zn(II) and for log K_2 the order: Hg(II) Zn(II) In(III) Cd(II). Log K_1 values for Hg(II) In(III), and Cd(II) were above 10 indicating that these metal ions form an extremely stable bond with sulfur. This enhanced stability is due to the formation of a second bond or a d - d bond between the metal ion and the sulfur atom. The d bonding with Zn(II) is not as great as with the other metal ions. The order is somewhat reversed for log K_2 and follows the order of decreasing electronegativities of the metal ion. This would indicate that the d bonding is not as pronounced in the second formation constant. Hg(II) again has a high log K_2 value because of the electronegativity of Hg(II) and the 4f and 5d polarizable electrons. The Ag(I)-thioglyeollic acid complex could not be calculated because Ag(I) precipitated with thioglycollic acid.

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