Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 100-101). Also available on the Internet.

Thesis (Ph. D.)--University of Michigan, 1931. / "Reprinted from Physical review, vol. 44, no. 5, September 1, 1933."

Universiẗat, Diss., 2003--München.

Thesis (Ph. D.)--University of Michigan, 1931. / "Reprinted from Physical review, vol. 44, no. 5, September 1, 1933."

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 100-101). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 1981. / Vita. Bibliography: leaves [135]-149.

Chlorination of 2-methyl-2-aryloxypropanoic acids with aqueous hypochlorous acid gives spiro chloro adducts in moderate to high yields. In chlorination of 2-methyl-2-(2-methylphenoxy)propanoic acids, 1,2-adducts are formed, while in the case of 2-methyl-2-(4-methylphenoxy)propanoic acids, 1,4-adducts are obtained. In addition to the spiro adducts, 2-methyl-2-(4-chlorophenoxy)propanoic acids in the former case, and 2-methyl-2-(2-chlorophenoxy)propanoic acids in the latter case are formed, respectively. No 6-chlorosubstituted products are detected on chlorination of any of the substrates. Chlorination of 2-methyl-2-(2,4-dimethylphenoxy)propanoic acid affords only the 1,4-adduct. However, chlorination of 2-methyl-2-(5-chloro-2,4-dimethylphenoxy)propanoic acid gives both the 1,2- and the 1,4-adduct. 2-Methyl-2-(3,5-di-t-butylphenoxyl)propanoic acid on chlorination yields the diastereomeric secondary chloro adduct, 8-chloro-7,9-di-t-butyl-3,3-dimethyl-1,4-dioxaspiro (4,5) deca-6,9-dien-2-one. Under neutral and non-polar conditions, most of the 1,2-adducts undergo a thermal rearrangement of the chlorine which is shown to be a (1,5) sigmatropic chlorine shift. The rearrangement rates are highly dependent on the nature of the substituents in the diene systems. Under acidic and non-nucleophilic conditions, most of the 1,4-adducts undergo an intramolecular 1,2 chlorine shift followed by aromatization to give the 3-chloro-substituted products. For the dienes in which the 3-position is originally substituted, successive 1,2 chlorine migrations and/or side chain substitution are observed. On the other hand, the 1,2-adducts under similar reaction conditions undergo an intermolecular 1,4 chlorine shift to give the 5-chlorosubstituted products. In the case that the 5-position is substituted by a methyl group, side chain substitution at the 5-methyl takes place. In the presence of added base, solvolyses of the 1,4-adducts in methanol affords simple solvolysis products and/or 1,2 carboxyl rearranged products. The kinetic studies of the solvolyses of the 1,4-adducts have been carried out. The results reveal the substituent effects on both the simple solvolysis displacement and the rearrangement reactions. / Graduate

Orientador: Ricardo de Lima Isaac / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-12T16:05:09Z (GMT). No. of bitstreams: 1 Siqueira_SidneiLima_M.pdf: 1474737 bytes, checksum: 071f5399e0fae4354b4e3c3bccc930ba (MD5) Previous issue date: 2008 / Resumo: Este trabalho consistiu em avaliar a capacidade de remoção da toxina Microcistina-Lr utilizando oxidação por cloro, dióxido de cloro e permanganato de potássio. Os ensaios foram realizados em escala de bancada em jar test simulando o processo de tratamento de água nas ETA's 3 e 4 da SANASA de Campinas. Foram realizados estudos com concentrações de 2.5, 5.0 e 10 µg/L de Mc-Lr quando se utilizou oxidação com cloro e dióxido de cloro e com concentrações de 2.5 e 5.0 µg/ L quando foi utilizado permanganato de potássio como oxidante. Foram feitos testes para verificação da influência da aplicação do oxidante antes e depois do alcalinizante com dosagens de 10µg/L de Mc-Lr. As utilizações do cloro e do permanganato se mostraram eficientes para a remoção da Mc-Lr, enquanto que com a utilização do dióxido de cloro, nenhuma remoção foi alcançada dentro das três horas de testes. Nos testes com aplicação do oxidante antes e depois do alcalinizante, não houve alterações significativas. Quando os testes foram feitos utilizando o tempo, os resultados foram similares para o cloro e permanganato de potássio, com a oxidação ocorrendo durante a primeira hora. Com o dióxido de cloro, a oxidação aconteceu somente durante a sexta hora. / Abstract: This work consisted in evaluate the capacity of removal of Microcystin-Lr toxin using oxidation with chlorine, chlorine dioxide and potassium permanganate. The tests were did using bench -scale tests in jar test equipment to simulated water treatment process of 3 and 4 WTP of SANASA Campinas. Study were did using 2.5, 5.0 and 10 µg/L Mc-Lr concentration when were used chlorine and chlorine dioxide oxidation and 2.5 and 5.0 µg/L Mc-Lr concentration when was used potassium permanganate oxidation. Were did tests to verify the influence of before and after alkali oxidant dosing with 10µg/L Mc-Lr. The chlorine and permanganate uses were efficient to Mc-Lr removal while chlorine dioxide no one removal was obtained with normal quantity used in Convencional Water Drinking Treatment Plant. When the tests were did using time, the results were silimary to chlorine and permanganate with the oxidation happened during the first hour. With chlorine dioxide oxidation, the oxidation happened only during the sixth hour. When the tests were did dosing. / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil

Orientadores: Christiane de Arruda Rodrigues, Rodnei Bertazzoli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-13T04:07:37Z (GMT). No. of bitstreams: 1 Figueiredo_RaulSebastiao_M.pdf: 1948808 bytes, checksum: acfbf0288c329a83e88728677892f09c (MD5) Previous issue date: 2009 / Resumo: Neste trabalho investiga-se o desempenho de eletrodos de difusão gasosa modificado com partículas de Cu, para a redução do oxigênio no processo de produção de cloro durante a eletrólise da salmoura. Para a realização dos experimentos voltamétricos foi inicialmente estudada, a reação anódica relativa à oxidação do íon cloreto. Utilizada uma célula de compartimento único, com anodo do tipo DSA com área de 1,5 cm2, contra eletrodo de EDG e eletrodo de referência de calomelano saturado (solução de KCl saturada) em solução de NaClO4 0,05 mol L-1 para a identificação do potencial de desprendimento do oxigênio. Posteriormente adicionou-se 20g/L de NaCl à solução de NaClO4 para observar o potencial de desprendimento do gás cloro na superfície do DSA. Nesses ensaios duas temperaturas foram analisadas: 25 °C e 70 °C. Na preparação dos catodos de difusão de oxigênio, foi usada uma massa precursora, composta pelo pigmento carbonoso Printex e suspensão de pó de PTFE. O catalisador introduzido foi o Cu metálico na forma de pó. O Cu foi introduzido na massa precursora utilizando diferentes métodos, na proporção de 10% m/m. Para que fosse possível chegar na porcentagem ótima de catalisador, estudos foram realizados com diferentes porcentagens de Cu (5%, 10%, 15%, 20%, 25%, 30%) sendo que a melhor foi de 10% m/m. Após as massas terem sido preparadas, os eletrodos de difusão gasosa foram sinterizados. Para a sinterização dos eletrodos de difusão gasosa (EDG) foi pesada 0,2 g da massa precursora e colocada no molde. O molde foi aquecido a uma temperatura de 340 °C para a sinterização do eletrodo, sob pressão de 146 kgf/cm2, durante 2 horas. Após a sinterização, os eletrodos foram submetidos a ensaios de permeabilidade. Em etapa subseqüente, os eletrodos de difusão gasosa foram usados nos estudos voltamétricos tendo sido submetidos a varreduras lineares de potencial de 0 a -2 V vs. ECS. Para analisar a reação de redução do oxigênio no EDG, a solução de trabalho foi 320g/L de NaOH pH 13,6. A seguir, foram realizados ensaios de eletrólise a corrente constante usando o EDG ou grafite pirolítico como catodos e o DSA como anodo. Nestes ensaios, utilizou-se uma célula com dois compartimentos, separados por uma membrana catiônica NafionÒ N242. Cada compartimento possuía um volume de 40 ml. Os eletrodos tinham área de 3,14 cm2. O anólito foi uma solução de 250 g/L NaCl com pH 3 ajustado com HCl concentrado e o católito 320 g/L NaOH. Durante as eletrólises o cloro dissolvido na forma de hipoclorito e o gás cloro foram quantificados por meio de iodometria. Nos ensaios de voltametria linear o eletrodo que obteve um melhor desempenho, foi o EDG modificado com 10 % Cu tendo mostrado uma redução de 1.95 V na diferença de potencial da célula quando comparado ao carbono pirolítico. Já com temperatura de 70°C o potencial diminuiu cerca de 1.2 V. / Abstarct: This work is investigating the performance of electrodes modified with gaseous diffusion of particles of Cu, for reduction of oxygen in the production of chlorine during the electrolysis of brine. Initially, the reaction was studied on the anodic oxidation of chloride ion. Using a single cell compartment, with the type DSA anode with an area of 1.5 cm2 as work of reference and the calomel electrode in KCl solution saturated cyclic voltammetries were performed using the NaClO4 solution of 0.05 mol L-1 for identifying the potential for evolution of oxygen. By adding 20g / L of NaCl in the solution of NaClO4 to see the potential for evolution of chlorine gas on the surface of the DSA. In these two tests were analyzed temperature: 25 °C and 70 °C. In preparing the cathodes of diffusion of oxygen, was used a mass precursor, composed of carbonaceous pigment Printex and suspension of the PTFE powder. The catalyst was introduced in the form of Cu metal powder. The Cu was introduced in the mass precursor using different methods, the proportion of 10% m / m. What could be reached in the great percentage of catalyst, studies were made with different percentages of Cu (5%, 10%, 15%, 20%, 25%, 30%) and the best was 10% m / m. After the bodies were prepared, the electrodes of gaseous diffusion were synthesized. For the sintering of the electrodes of gaseous diffusion (GDS) was weighed 0.2 g of mass precursor and placed on the mold. The mold was heated to a temperature of 340 ° C for the sintering of the electrode, under pressure of 146 kgf/cm2 for 2 hours. After sintering, the electrodes were being tested for permeability. In subsequent stage, the electrodes of gaseous diffusion were used in voltammetric studies and submitted to linear potential sweeps from 0 to-2V vs. ECS. To examine the reactions of reduction of oxygen in the GDS, the solution of work was 320g / L NaOH pH 13.6. Then, tests were performed using constant current electrolysis to the GDS or pyrolytic graphite as cathode and DSA as anode. In these tests, using a cell with two compartments, separated by a membrane cationic Nafion N242. Each compartment has a volume of 40mL. The electrodes were area of 3.14 cm2. The anolyte was a solution of 250g / L NaCl at pH 3 adjusted with concentrated HCl and the catholyte was a solution of 320g / L NaOH. During the electrolyses the chlorine dissolved in the form of hypochlorite and chlorine gas were quantified by iodometry titration. The electrode that had a better performance as a cathode, the GDS was modified with 10% Cu having shown a reduction of 1.95 V difference in potential in the cell when compared to pyrolytic carbon. Already with a temperature of 70 °C decreased the potential 1.2 V. / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Abstract Washing during kraft pulping can be divided into two separate areas each with its own distinct features: namely brownstock washing and washing in bleaching. Research interest has so far concentrated mostly on investigating brownstock washing and factors affecting its efficiency. Pulp washing in bleaching, however, has been practically neglected. The basic phenomena are the same as in brownstock washing, but there are differences which have not been taken into consideration to a sufficient extent. This less explored area is the focus of this research. In this thesis, it is shown that brownstock washing and pulp washing between bleaching stages are distinct areas with their own specific features. They differ for example in terms of the composition and molecular size of the impurities in the pulp suspension. Various process conditions, pH, temperature and so on cause further differences between washing in bleaching and brownstock washing. The removal of specific compounds can be clearly affected by the appropriate selection of wash liquor. It is shown that the dynamic behaviour during washing is different for different compounds and depends on the properties of the wash water. The key element is to find the most harmful compounds in specific positions in bleaching and on the basis of that finding, to determine the most suitable wash liquor system. Chemical oxygen demand (COD) is a widely used method for evaluating the washing result, but as a collective measurement variable it does not describe the actual compounds that cause the "loss" of bleaching chemicals. Studies have shown that many compounds contribute to COD load but ultimately most of them have no real effect on the bleaching result. A suggestion for more precise definition of wash loss is offered than COD.