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Thesis (Ph. D.)--University of Wisconsin--Madison, 1942. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 47-49).

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Two new general synthetic routes to phosphines were developed. The first method described directly converts phosphonates to phosphine oxides using organometallic nucleophiles. This reaction proceeds through a five-coordinate phosphorus intermediate. The second synthetic method uses a deprotonated secondary phosphine oxide for nucleophilic addition to an alkyl halide to form a tertiary phosphine oxide. This reaction proceeds through a standard SN2 mechanism, however in extreme cases a competitive electron transfer reaction was observed. These syntheses were used to make a new dimethyl phosphine (MeJPhos). This phosphine was used as a ligand for metal complexes and compared against a series of structurally related (JohnPhos) phosphines. MeJPhos was found to be the strongest electron donor in the series MeJPhos, EtJPhos, iPrJPhos, CyJPhos, and tBuJPhos. These ligands were then used to study structural effects of ligands on Buchwald-Hartwig cross-coupling catalysis. It was found that only tBuJPhos performed catalytically. This observation is likely due to the smaller steric profile of the other JohnPhos ligands. Specifically, it is the inability to perform the reductive elimination step of the catalytic cycle that prevents turnover. Ozonolysis was used to oxidize alkenes to aldehydes directly. Typically with ozonolysis, a secondary ozonide is formed as the product that must be chemically reacted in a subsequent step. By trapping out the immediate chemical precursor to the secondary ozonide with water, the formation of secondary ozonides was avoided. This method produced aldehydes directly from aryl alkenes in good to excellent yields. This dissertation includes previously published and unpublished co-authored material.

The reactions of aromatic hydrocarbons represent a major area of uncertainty in urban atmospheric photochemistry. Much effort has been spent studying the simulated atmospheric oxidation chemistry of model aromatics, such as toluene, in order to delineate their reaction mechanisms. These studies are motivated both by interest in fundamental processes and a desire to discover an aromatic's contribution to the formation of ozone in polluted ambient atmospheres. Previous work on toluene includes both product studies and proposed mechanisms. In all previous studies, the combined product yields are half or less of the initially reacted toluene. A major reason for the poor carbon balances found in these studies in the precipitation of intermediate reaction products from the gas phase to the reaction walls. We have studied the oxidation process by blacklight irradiation of 1-10 ppm each of toluene and oxides of nitrogen in 22-liter pyrex flasks, in zero-air at 50% relative humidity. The products were recovered from the walls by exrtraction with methanol or dichloromethane. Some gas-phase products were recovered in the solvent as well. The extracts were analyzed on a Finnigan MAT triple stage quadrupole mass spectrometer/data system by direct probe injection. Once their molecular weights were determined, the products were fragmented by collision-induced-dissociation (CID) in the middle quadrupole to produce characteristic daughter ions. To assist in the spectral interpretation, toluene in three isomeric forms was subjected to simulated atmospheric reaction. In addition to normal (H8) toluene, methyl-deuterated (D3) and per-deuterated (D8) toluene were used. This study confirmed the existence of a number of products identified in past studies, confirmed the formation of some products which have been hypothesized in several proposed mechanisms for toluene oxidation, identified a number of previously unidentified and unproposed products. Detailed mechanistic steps have been outlined for all reaction products' formation and destruction. Other analytical techniques including GC, GC/MS, and HPLC, have supplemented the MS/MS analysis. These results and the further study of the types of compounds identified should make a significant contribution to the understanding of atmospheric aromatic systems.

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The purpose of this study was to compare the effectiveness of ozone treatments on the production of methane from three samples of native cellulose. Ozone has been used to increase hydrolysis of native cellulose but not in conjunction with methane generation studies. One sample was not treated with ozone to serve as a control, while the second sample was treated with 0.1 ppm ozone and third sample was treated with 1.0 ppm ozone. The gas chromatographic measurements of methane from each sample was used to determine the effectiveness of ozone.The difference in methane production between the three sample means was analyzed by the Analysis of Varience test. The analysis of the mean methane data from the three samples were significantly different from each other and based upon this analysis, it was concluded that ozone was effective. However, as the study proceeded the methane production of the treated samples was converging. Thus, it was suggested that further research using ozone concentration levels between 0.1 ppm and 1.0 ppm should be tested to determine the optimal ozone level needed for the enhancement of methane production from a cellulosic source.Ball State UniversityMuncie, IN 47306

Acquiring in depth knowledge of the ozone oxidation of surface-bound fullerenes advances the understanding of fullerene fate in the environment, as well as the reactivity of ozone with carbonaceous nanomaterials. Recent ultrahigh vacuum studies of the reaction of gasphase ozone with surface-bound fullerenes have made it possible to observe the formation and subsequent thermal decomposition of the primary ozonide (PO). As the use of nanomaterials, such as C₆₀, continues to increase, the exposure of these molecules to humans and the environment is of growing concern, especially if they can be chemically altered by common pollutants. These experiments are made possible by combining ultrahigh vacuum surface analysis techniques with precision dosing using a pure O₃ gas source. The experimental setup also provides the capability of monitoring surface-bound reactants and products in situ with reflection-absorption IR spectroscopy, while gas-phase products are detected with a mass spectrometer. Our results indicate that ozone adds across a 6/6 bond on the C₆₀ cage, forming an unstable intermediate, the primary ozonide. The observed initial reaction probability for the PO is γ = 4.1 x 10⁻³. Energies of activation for the formation and decomposition of the PO were obtained via temperature-dependent studies. After formation, the primary ozonide thermally decomposes into the Criegee Intermediate which can rearrange or, upon further exposure to ozone, react with another ozone molecule to form a variety of products such as carbonyls, anhydrides, esters, ethers, and ketenes. Larger fullerenes (C₇₀, C₇₆, C₇₈, and C₈₄) were also exposed to gas-phase ozone, in order to observe the reaction rate for ozonolysis and to propose an initial mechanism for ozone exposure. The results indicate that the structure of the fullerenes has little to no impact on the rate of oxidation via ozone. Lastly, Terbium endohedral were exposed to ozone, in an effort to determine whether ozone was capable of oxidizing both the outer fullerene cage, as well as the Tb atom sequestered inside. The preliminary XPS data suggests ozone oxidizes both within an hour of continuous exposure. Understanding this atmospherically-relevant reaction from both a mechanistic and kinetic standpoint will help predict the environmental fate of fullerenes and their oxides. / Ph. D.

The complexity of the processes whereby organic species are degraded in the atmosphere prevents many of the individual species (intermediates or products) from being unambiguously identified. Laboratory work necessarily focuses therefore on studies of idealised proxies with the aim of increasing general understanding of the physical and chemical processes which occur on particles and the types of species which they produce. Studies of the ubiquitous proxy oleic acid have resulted in the development of complex reaction schemes describing the various products and intermediates. These schemes include a diverse range of reactions and rates, thus highlighting the complications associated even with a relatively simple system. This thesis describes novel experimental studies designed to increase understanding of heterogeneous ozonolysis reactions of organic species in the aerosol phase using infrared spectroscopy as the principal analytical method. Reactions have been studied in solution (supported by off-line mass spectrometry), in thin films and in aerosols. The sensitivity of the infrared technique has also enabled the kinetics of reactions in thin films and aerosols to be followed. These methods were applied to both single- and mixed-component systems. Product studies successfully identified a number of primary and secondary species in the ozonised systems, with the secondary products formed from association reactions of the Criegee Intermediates with other species present (including self-reaction). In the mixed organic system these products were found to have originated from both a single reactant and from cross reactions between moieties from two different reactants. At low relative humidity, the ozonolysis reaction rates were monitored through the loss of the reactant species by infrared spectroscopy in the thin film and aerosol phase to give reactive uptake coefficients (gamma). At high relative humidity, the formation of products was followed. For the single-component thin films, the values obtained were gamma = 7.8 x 10-5 for stilbene and gamma = 2.0 x 10-7 for anthracene. In thin mixed films of oleic acid and stilbene, segregation occurred which prevented the effect of mixing upon the rate to be measured. A reactive uptake of gamma = 6.8 x 10-5 was obtained, identical to that of pure oleic acid. In the particle phase, the functional form of the reaction kinetics was found to be dependent on the type of particle. Pure stilbene and mixed oleic/stilbene aerosols were highly reactive and it proved necessary to treat reactive uptake coefficients under both diffusion-limited and surface-only reaction scenarios. For stilbene, the values obtained were gamma = 1.5 x 10-3 and gamma = 5.3 x 10-3 respectively. Spectral limitations in the mixed system meant that only the reaction of stilbene could be followed, giving gamma = 4.4 x 10-3 and gamma = 10.0 x 10-3 respectively. The enhanced rate in the mixture was attributed to secondary reactions. Anthracene and oleic acid coated particles were treated using a Langmuir-Hinshelwood mechanism from which the parameters KO3 (ozone partitioning coefficient) and kImax (maximum pseudo-first-order rate coefficient) could be extracted. For anthracene ozonolysis KO3 = 1.4 x 10-16 cm3 molecule-1 and kImax = 3.5x10-2 s-1. For oleic acid coated onto ammonium sulfate aerosols, values obtained were KO3 = 2.35 x 10-15 cm3 molecule-1 and kImax = 0.56 s-1 at low RH% and KO3 = 1.71 x 10-16 cm3 molecule-1 and kImax =0.33 s-1 at high RH%. The reduction in reactivity with increased RH% is principally attributed to the effect of surface polarity on ozone absorption.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Chemistry. / Vita. / Includes bibliographical references. / Ph.D.