No description available.

Yes / Reverse Osmosis (RO) is widely used for separating organic and inorganic pollutants in wastewater. In this research, the one-dimensional steady state model of a spiral wound RO for the removal of phenol from wastewater, was simulated using gPROMS software to identify optimal design and operating parameters. The design parameters included the membrane length, width and feed spacer channel and operating conditions included temperature and pressure of the RO process. The optimal design parameters were able to maximise the removal of phenol from wastewater. The simulation results showed that the removal of phenol from wastewater was significantly influenced by the combination of membrane width, operating pressure, and feed temperature. The four main parameters (permeate concentration, solute flow, solute rejection, and water flux) that govern the performance of a reverse osmosis membrane were found to be influenced by the design and operating conditions.

Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior. The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.

Ziel dieser Arbeit war die Entwicklung von Methoden zur Synthese von auf Phenol basierenden Naturstoffen. Insbesondere wurde bei der Methodenentwicklung die Nachhaltigkeit in den Vordergrund gerückt. Dies bedeutet, dass durch die Zusammenfassung mehrerer Syntheseschritte zu einem (Tandem-Reaktion) beispielsweise unnötige Reaktionsschritte vermieden werden sollten. Ferner sollten im Sinne der Nachhaltigkeit möglichst ungiftige Reagenzien und Lösungmittel verwendet werden, ebenso wie mehrfach wiederverwertbare Katalysatoren zum Einsatz kommen. Im Rahmen dieser Arbeit wurden Methoden zum Aufbau von Biphenolen mittels Pd/C-katalysierten Suzuki-Miyaura-Kupplungen entwickelt. Diese Methoden sind insofern äuÿerst ezient, da der ansonsten gebräuchliche Syntheseweg über drei Reaktionsschritte somit auf lediglich eine Reaktionsstufe reduziert wurde. Weiterhin wurden die Reaktionsbedingungen so gestaltet, dass einfaches Wasser als vollkommen ungiftiges Lösungsmittel verwendet werden konnte. Des Weiteren wurde für diese Reaktionen ein Katalysator gewählt, der einfach durch Filtration vom Reaktionsgemisch abgetrennt und für weitere Reaktionen mehrfach wiederverwendet werden konnte. Darüber hinaus konnte durch die Synthese von mehr als 100 Verbindungen die breite Anwendbarkeit der Methoden aufgezeigt werden. Mit den entwickelten Methoden konnten 14 Naturstoffe - z. T. erstmals - synthetisiert werden. Derartige Stoffe werden u. a. von den ökonomisch bedeutenden Kernobstgewächsen (Äpfeln, Birnen) als Abwehrmittel gegenüber Schädlingen erzeugt. Folglich konnte mit Hilfe dieser Methoden ein Syntheseweg für potentielle Pflanzenschutzmittel entwickelt werden. Im zweiten Teil dieser Arbeit wurde ein Zugang zu den sich ebenfalls vom Phenol ableitenden Chromanonen, Chromonen und Cumarinen untersucht. Bei diesen Untersuchungen konnte durch die Entwicklung zweier neuer Tandem-Reaktionen ein nachhaltiger und stufenökonomischer Syntheseweg zur Darstellung substituierter Benzo(dihydro)pyrone aufgezeigt werden. Durch die erstmalige Kombination der Claisen-Umlagerung mit einer Oxa-Michael-Addition bzw. konjugierten-Addition wurden zwei vollkommen atomökonomische Reaktionen miteinander verknüpft und somit eine überaus effiente Synthese von allyl- bzw. prenylsubstituierten Chromanonen und Chromonen ermöglicht. Ferner konnten durch die Anwendung einer Claisen-Umlagerung-Wittig-Laktonisierungs-Reaktion allyl- bzw. prenylsubstituierte Cumarine erhalten werden. Herausragendes Merkmal dieser Methoden war, dass in nur einem Schritt der jeweilige Naturstoffgrundkörper aufgebaut und eine lipophile Seitenkette generiert werden konnte. Die Entwicklung dieser Methoden ist von hohem pharmazeutischem Stellenwert, da auf diesen Wegen Verbindungen synthetisiert werden können, die zum einem über das notwendige pharmakologische Grundgerüst verfügen und zum anderen über eine Seitenkette, welche die Aufnahmefähigkeit und damit die Wirksamkeit im Organismus beträchtlich erhöht. Insgesamt konnten mittels der entwickelten Methoden 15 Chromanon-, Chromon- und Cumarin-Naturstoffe z. T. erstmals synthetisiert werden. / The aim of this work was the development of methods for the synthesis of natural products based on phenol. In particular, in developing methods, sustainability has been brought to the fore. This means that, for example, unnecessary reaction steps should be avoided by the combination of several synthetic steps to a (tandem reaction). Furthermore, non-toxic as possible in terms of sustainability reagents and solvents should be used, as well as multiple reusable catalysts are used. In this work, methods have been developed for the synthesis of bisphenols using Pd / C-catalyzed Suzuki-Miyaura coupling reactions. These methods are so far äuÿerst e? Cient, since the otherwise common synthetic route was thus reduced to merely a reaction stage, three reaction steps. Furthermore, the reaction conditions were designed to plain water could be used as a completely non-toxic solvent. It was also elected a catalyst for these reactions, which could be easily separated by filtration from the reaction mixture and reused several times for further reactions. In addition, it could be demonstrated through the synthesis of more than 100 compounds, the broad applicability of the methods. ., For the first time T. - - Using the methods developed 14 natural compounds could be synthesized. Such substances are among others generated by the economically important pome fruit crops (apples, pears) as a defense against pests. Consequently, it could be developed using these methods, a synthetic route for potential plant protection products. In the second part of this work, access to the likewise derived from phenol chromanones, chromones and coumarins was investigated. In these studies, a sustainable and economical route in stages to represent substituted benzo (dihydro) pyrones could be demonstrated by the development of two new tandem reactions. The initial combination of the Claisen rearrangement with an oxa-Michael addition or conjugated addition of two perfectly atom-economical reactions were interlinked and thus allows a very effiente synthesis of allyl or prenylsubstituierten chromanones and chromones. Furthermore or prenylsubstituierte coumarins could be obtained by the application of a Claisen rearrangement Wittig lactonization reaction allyl. The outstanding feature of these methods was that built up in only one step of the respective natural product base and a lipophilic side chain could be generated. The development of these methods is of great pharmaceutical importance, since these paths compounds can be synthesized on a the necessary pharmacological Backbone and on the other hand have a side chain, which increases the absorption and thus the effectiveness in the body considerably. Overall, z. T. were synthesized using the methods developed Chromanon- 15, chromone and coumarin-natural products for the first time.

<p> High molecular weight poly(ethylene oxide) (PEO) is used in conjunction with a cofactor such as phenol formaldehyde resin (PFR) as flocculants for newsprint manufacture. The objectives of the work described in this thesis were to prepare flocculants superior to PEO and to determine the flocculation mechanism. A series of novel comb copolymers consisting of a polyacrylamide backbone with short pendant poly(ethylene glycol) (PEG) chains was prepared and characterized. Additionally, polymerization conversion curves and reactivity ratios were measured. An interesting finding was that the reactivity of the macromonomer in free radical copolymerization decreased with PEG chain length. </p> <p> Flocculation results with both model latex dispersions and commercial wood pulp suspensions showed that copolymer chain length was the most important variable ; molecular weights greater than 3 million were required for good flocculation. On the other hand, the PEG pendant chains could be as short as 9 ether repeat units. Also, only 1 to 2 PEG chains for every 100 acrylamide backbone moieties were required. </p> <p> No published flocculation mechanisms could predict all the behaviors of the PEO or copolymer system. A new mechanism called complex bridging was proposed. According to this mechanism PEO or copolymer chains aggregate in the presence of cofactor to form colloidally dispersed polymer complex which heteroflocculates with the colloidal particles. </p> <p> Given in this work is the first explanation of the requirement for extremely high PEO or copolymer molecular weights for flocculation. It is proposed that polymer chains with molecular weights less than 106 collapse in the presence of PFR to an inactive precipitate before flocculation can occur whereas complexes based on very high molecular weight PEO collapse slowly enough to permit flocculation. </p> <p> Published mechanistic studies are hindered by the fact that PFR has poorly defined structures. It is shown for the first time in this work that welldefined, linear, poly(p-vinyl phenol) (PVPh) is an effective cofactor. </p> / Thesis / Doctor of Philosophy (PhD)

published_or_final_version / abstract / Civil Engineering / Doctoral / Doctor of Philosophy

The present work verified the efficiency of electro-Fenton to destroy phenolic compounds present in Stripping Aircraft Wastewater. This research aimed to elucidate the influence of the catalyst nature, its concentration and of electric current density in efficiency of electro-Fenton process using an indivisible cell with a carbon felt cathode and platinum or borod doped diamond anodes. The experiments compared the effect of these variables to destroy phenol, cresols and their intermediates. The compounds and many intermediates formed were identified in High Perfomance Liquid Chromatograph and allowed obtaining apparent and/or absolute constants and simplified degradation mechanisms. In optimum conditions, measures of Total Organic Carbon showed high mineralization rates. At the end, the application of electro-Fenton process to high organics loads of real Stripping Aircraft wastewater allowed obtaining almost complete mineralization replacing Pt anode by Boron Doped Diamond.

A biomassa lignicelul&oacute;sica tem sua estrutura composta por celulose, hemicelulose e lignina. Dentre essas, a lignina tem se mostrado interessante por ser uma fonte precursora sustent&aacute;vel de fragmentos arom&aacute;ticos antes obtidos apenas de combust&iacute;veis f&oacute;sseis. Sua estrutura &eacute; composta por res&iacute;duos de fenilpropan&oacute;ides p-hidroxibenzeno (H), guaiacil (G) e siringil (S) unidas por liga&ccedil;&otilde;es C&ndash;C e C&ndash;O&ndash;C em que a liga&ccedil;&atilde;o &#946;&ndash;O&ndash;4 &eacute; a predominante (mais de 50%). Devido &agrave; sua complexidade estrutural e conformacional, a clivagem de suas liga&ccedil;&otilde;es &eacute; pouco seletiva e a caracteriza&ccedil;&atilde;o dos fragmentos resultantes &eacute; complexa. Uma estrat&eacute;gia comumente empregada para evitar esses desafios &eacute; o uso de modelos mais simples. Entretanto, poucas metodologias s&atilde;o reportadas na literatura para a sua s&iacute;ntese e a maioria delas envolve o emprego de halocetonas. O presente trabalho desenvolveu duas novas metodologias promissoras para s&iacute;ntese desses olig&ocirc;meros, contendo liga&ccedil;&atilde;o &#946;&ndash;O&ndash;4 por meio da qu&iacute;mica de diazo: (a) rea&ccedil;&atilde;o de inser&ccedil;&atilde;o O&ndash;H entre fenol e &#945;&ndash;aril diazocetonas, e (b) compostos &#945;&ndash;diazo &#946;-ceto&eacute;ster. Ademais, a utiliza&ccedil;&atilde;o de mon&ocirc;meros contendo a fun&ccedil;&atilde;o fenol e diazocetona no mesmo anel permitiria a s&iacute;ntese de cadeias de diversos tamanhos em uma &uacute;nica etapa. Como ponto de partida para o estudo, limitou-se &agrave; s&iacute;ntese de d&iacute;meros, visando entender a rea&ccedil;&atilde;o de inser&ccedil;&atilde;o O&ndash;H. Os produtos desejados foram obtidos em rendimentos de 27&ndash;51% ap&oacute;s cat&aacute;lise com Cu(hfac)2. Por fim, os modelos de lignina propriamente ditos foram sintetizados ap&oacute;s simples adi&ccedil;&atilde;o ald&oacute;lica e redu&ccedil;&atilde;o em rendimentos globais de 51&ndash;78%. Os estudos envolvendo a inser&ccedil;&atilde;o de fenol em &#945;&ndash;diazo &#946;-ceto&eacute;ster mostraram resultados promissores, corroborando para uma nova estrat&eacute;gia sint&eacute;tica para a obten&ccedil;&atilde;o de modelos de lignina. Novos estudos em nosso laborat&oacute;rio est&atilde;o sendo desenvolvidos para se obter resultados mais conclusivos. / Lignocellulosic biomass is composed of cellulose, hemicellulose and lignin. Among these, the macromolecule lignin has widely received attention as an interesting source of aromatic building blocks to replace those currently obtained from fossil&ndash;based fuels. Lignin is composed by units of phenylpropanoids p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) linked by C&ndash;C and C&ndash;O bonds which &#946;&ndash;O&ndash;4 linkages are dominant by more than 50%. Unfortunately, due to the complex structure and 3D arrangement of lignin, it is difficult to control selectivity during its degradation as well as characterize the resulting fragment. A common strategy to avoid these challenges is the use of model substrates; however, few methods exist for the synthesis of these models oligomers. The present work developed two promising routes towards the synthesis of these oligomers containing &#946;&ndash;O&ndash;4 linkages through use of diazo chemistry: (a) O&ndash;H insertion with a phenol and &#945;&ndash;aryldiazoketones, and (b) &#945;&ndash;diazo &#946;&ndash;ketoether compounds. Additionally, monomers containing a phenol and diazoketone unit on the same aromatic ring could allow for the synthesis of a variety of side chains in a single step. We began our studies on the synthesis of dimers via O&ndash;H insertion and obtained 27&ndash;51% yield of the desired products using catalytic Cu(hfac)2. The mimetic lignin models were synthesized after simple Aldol addition and reduction in 51&ndash;78% overall yield. Our work involving this O&ndash;H insertion into &#945;&ndash;diazo &#946;&ndash;ketoether is a promising strategy to rapidly synthesize lignin model oligomers and is an active area of research within our lab.

Os compostos fenólicos, quando em altas concentrações na água, são poluentes de alta periculosidade, difíceis de serem eliminados até mesmo por métodos convencionais, como por exemplo, a biorremediação microbiológica dos lodos ativados e os métodos físico-químicos. Sabendo da presença dos fenóis em muitos efluentes industriais se faz necessário o estudo de novos processos para o tratamento desses efluentes que possuam aplicações eficazes e, sobretudo, ecologicamente corretas. A presente pesquisa visou a degradação de poluentes fenólicos em soluções aquosas através da oxidação enzimática com tirosinase imobilizada em quitosana. A contribuição tecnológica relaciona-se com a possibilidade de aplicação do estudo em escala industrial em processos de tratamento de efluentes industriais que contenham poluentes fenólicos. Fenóis como o 4-clorofenol, 4-cresol, 4-nitrofenol e o próprio fenol, foram utilizados em ensaios de oxidação enzimática em vaso agitado, em regime dinâmico, em processo de batelada, temperatura de 45°C e três faixas de concentração enzimática (40, 60 e 80 U/ml). Além disso, foram testadas três formas de quitosana utilizadas na imobilização enzimática e aplicadas nos processos de oxidação de fenol: esferas, flocos e micro partículas de quitosana. A enzima tirosinase foi eficiente na degradação de fenol, 4-cresol e 4-clorofenol, diminuindo consideravelmente a concentração destes poluentes nas soluções aquosas. Porém, a tirosinase não oxidou significativamente o 4-nitrofenol. Verificou-se que o efeito de alguns substituintes do anel aromático do fenol e a posição desse substituinte no anel aromático, exerce influência direta na atividade da enzima durante as reações oxidativas envolvendo os compostos fenólicos. Embora o presente estudo tenha apresentado bons resultados na remoção de alguns compostos fenólicos em soluções aquosas por meio da oxidação de tais poluentes pela enzima tirosinase imobilizada em quitosana, o complexo enzima-suporte não apresentou a mesma eficiência nos ensaios subseqüentes, nos quais foi estudada a reutilização da enzima imobilizada. / The phenolic compounds when in high concentrations in water are extremely dangerous pollutants and difficult to be eliminated even by conventional methods such as the microbiological bioremediation with activated sludge and physico-chemical methods. Phenols are present in many industrial effluents and is necessary to develop new and effective processes for the treatment of that effluents and, if possible, environmentally friendly. This research aimed the degradation of phenolic pollutants in aqueous solutions by enzymatic oxidation with tyrosinase immobilized in chitosan. Phenols such as 4-chlorophenol, 4-cresol, 4-nitrophenol and phenol, had been used in assays of enzymatic oxidation in an agitated reactor, in dynamic regime, in a batch process, temperature of 45°C and three values of enzymatic concentration ( 40, 60 and 80 U/ml). In addition, three forms of chitosan had been used in enzymatic immobilization and applied in the processes of oxidation of phenol: pellets, flakes and small particles of chitosan. Tyrosinase was efficient in the degradation of phenol, 4-cresol and 4-chlorophenol, reducing significantly the concentration of these pollutants in aqueous solutions. However, tyrosinase did not oxidized 4-nitrophenol. It was verified that the effect of some substitutes and their position in the aromatic ring has a direct influence on the activity of the enzyme during the oxidative reactions involving phenolic compounds. Although this study has shown good results in the removal of some phenolic compounds in aqueous solutions through the oxidation of such pollutants by the tyrosinase immobilized on chitosan, the enzyme-support did not present the same efficiency in subsequent assays, in which we studied the reuse of the immobilized enzyme.

A biomassa lignicelul&oacute;sica tem sua estrutura composta por celulose, hemicelulose e lignina. Dentre essas, a lignina tem se mostrado interessante por ser uma fonte precursora sustent&aacute;vel de fragmentos arom&aacute;ticos antes obtidos apenas de combust&iacute;veis f&oacute;sseis. Sua estrutura &eacute; composta por res&iacute;duos de fenilpropan&oacute;ides p-hidroxibenzeno (H), guaiacil (G) e siringil (S) unidas por liga&ccedil;&otilde;es C&ndash;C e C&ndash;O&ndash;C em que a liga&ccedil;&atilde;o &#946;&ndash;O&ndash;4 &eacute; a predominante (mais de 50%). Devido &agrave; sua complexidade estrutural e conformacional, a clivagem de suas liga&ccedil;&otilde;es &eacute; pouco seletiva e a caracteriza&ccedil;&atilde;o dos fragmentos resultantes &eacute; complexa. Uma estrat&eacute;gia comumente empregada para evitar esses desafios &eacute; o uso de modelos mais simples. Entretanto, poucas metodologias s&atilde;o reportadas na literatura para a sua s&iacute;ntese e a maioria delas envolve o emprego de halocetonas. O presente trabalho desenvolveu duas novas metodologias promissoras para s&iacute;ntese desses olig&ocirc;meros, contendo liga&ccedil;&atilde;o &#946;&ndash;O&ndash;4 por meio da qu&iacute;mica de diazo: (a) rea&ccedil;&atilde;o de inser&ccedil;&atilde;o O&ndash;H entre fenol e &#945;&ndash;aril diazocetonas, e (b) compostos &#945;&ndash;diazo &#946;-ceto&eacute;ster. Ademais, a utiliza&ccedil;&atilde;o de mon&ocirc;meros contendo a fun&ccedil;&atilde;o fenol e diazocetona no mesmo anel permitiria a s&iacute;ntese de cadeias de diversos tamanhos em uma &uacute;nica etapa. Como ponto de partida para o estudo, limitou-se &agrave; s&iacute;ntese de d&iacute;meros, visando entender a rea&ccedil;&atilde;o de inser&ccedil;&atilde;o O&ndash;H. Os produtos desejados foram obtidos em rendimentos de 27&ndash;51% ap&oacute;s cat&aacute;lise com Cu(hfac)2. Por fim, os modelos de lignina propriamente ditos foram sintetizados ap&oacute;s simples adi&ccedil;&atilde;o ald&oacute;lica e redu&ccedil;&atilde;o em rendimentos globais de 51&ndash;78%. Os estudos envolvendo a inser&ccedil;&atilde;o de fenol em &#945;&ndash;diazo &#946;-ceto&eacute;ster mostraram resultados promissores, corroborando para uma nova estrat&eacute;gia sint&eacute;tica para a obten&ccedil;&atilde;o de modelos de lignina. Novos estudos em nosso laborat&oacute;rio est&atilde;o sendo desenvolvidos para se obter resultados mais conclusivos. / Lignocellulosic biomass is composed of cellulose, hemicellulose and lignin. Among these, the macromolecule lignin has widely received attention as an interesting source of aromatic building blocks to replace those currently obtained from fossil&ndash;based fuels. Lignin is composed by units of phenylpropanoids p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) linked by C&ndash;C and C&ndash;O bonds which &#946;&ndash;O&ndash;4 linkages are dominant by more than 50%. Unfortunately, due to the complex structure and 3D arrangement of lignin, it is difficult to control selectivity during its degradation as well as characterize the resulting fragment. A common strategy to avoid these challenges is the use of model substrates; however, few methods exist for the synthesis of these models oligomers. The present work developed two promising routes towards the synthesis of these oligomers containing &#946;&ndash;O&ndash;4 linkages through use of diazo chemistry: (a) O&ndash;H insertion with a phenol and &#945;&ndash;aryldiazoketones, and (b) &#945;&ndash;diazo &#946;&ndash;ketoether compounds. Additionally, monomers containing a phenol and diazoketone unit on the same aromatic ring could allow for the synthesis of a variety of side chains in a single step. We began our studies on the synthesis of dimers via O&ndash;H insertion and obtained 27&ndash;51% yield of the desired products using catalytic Cu(hfac)2. The mimetic lignin models were synthesized after simple Aldol addition and reduction in 51&ndash;78% overall yield. Our work involving this O&ndash;H insertion into &#945;&ndash;diazo &#946;&ndash;ketoether is a promising strategy to rapidly synthesize lignin model oligomers and is an active area of research within our lab.