No description available.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 125-132). Available also in a digital version from Dissertation Abstracts.

In this thesis the electrochemical reduction of nitrobenzene in a methanol / sulphuric acid electrolyte is studied. Major products are shown to be para-anisidine, ortho-anisidine, para-aminophenol and aniline. A simple reaction model is derived, based on the well accepted mechanism for nitrobenzene reduction. Kinetic constants are determined from experimental results using a laboratory scale glass cell. Predictions as to potential - current behaviour and product formation as a function of mass transport and current density are made. It is shown that the rate of mass transport and the current density are crucial parameters in determining the chemical yields of the products formed. High rates of mass transfer and low current densities favour para-anisidine formation, whilst aniline is preferred under poor mass transfer conditions and high current densities. Results from a bench scale parallel plate cell fit the model predictions for the conditions used. The use of packed and fluidised bed electrodes is also investigated for the production of para-anisidine. Using copper particles, serious dissolution is shown to occur which leads to an increased yield of aniline. The copper dissolution is shown to have an electro-catalytic effect for the reduction of nitrobenzene to aniline. Results using Monel as an electrode material showed an improvement over copper, but preferential dissolution of nickel occurred. On the basis of the work in this thesis, copper or Monel packed and fluidised bed electrodes are not suitable for the production of para-anisidine.

Thesis (Ph. D.) -- California Institute of Technology, 2010. / Title from home page (viewed 03/22/2010). Advisor and committee chair names found in the thesis' metadata record in the digital repository. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xiv, 139 p.; also includes graphics (some col.) Includes bibliographical references (p. 132-139). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Nathan L. Bauld. Vita. Includes bibliographical references.

Using a combination of solid-state NMR techniques including Tip measurements, dynamic line shape analyses and 2D EXSY data, a variety of intramolecular motions including rotations of methyl, t-butyl, t-amyl, phenyl, trimethylammonium and trimethylphosphonium groups in a series of quaternary ammonium and phosphonium salts have been investigated. Where possible, activation parameters Ea, △G+/-, △H+/- and △S+/- have been derived. A range of values was recorded, especially for △S+/- which ranged from +75 JK−1 mol−1 for a phenyl group to -57 JK−1 mol−1for a t-butyl group. It was shown that 13p and 31p T1p measurements from CP/MAS spectra can give quantitative information on the kinetics of intramolecular motions that agree with line shape analysis. Recent work using X-ray crystallography has suggested that some derivatives of bicycle [3.3.1] nonane show evidence of conformational equilibria in the solid state. Using 13CP/MAS NMR, 22 derivatives of bicycle [3.3.1] nonane were studied, some at variable temperature. No evidence of conformational equilibria was observed in the chosen compounds. Solid-state NMR has been used to follow the kinetics of ring- chain tautomerism in a bicyclic tetrahydro-1,3-oxazine derivative. This was found to form initially the metastable chain on crystallisation, which then cyclises. The kinetics of the cyclisation were followed and the activation energy for the solid-state reaction was derived. In contrast to this, a related pyrimidine derivative has been found to form initially the metastable ring on cyclisation which quickly ring opens to the chain.

Not available / text

No description available.

No description available.