Ph.d.

Azobenzene derivatives have been shown to act as a molecular switch when ex- posed to an applied electric field. Many applications require the switching molecule to be adsorbed on a surface. The behavior of chemisorbed N-(2-mercaptoethyl)-4- phenylazobenzamide on a Au(111) surface has been investigated using a mean-field theoretical approach for azobenzene in alkylthiol monolayers and density functional theory calculations at the zero-density limit. Azobenzene switching in monolayers was found to be dependent on surface coverage, as well as the strength and polarity of an electric field. In the zero-density regime, azobenzene derivatives adopted paral- lel and upright geometries for both trans and cis isomers. Charged states for upright, adsorbed structures were also analyzed and were found to lower the isomerization energy barrier. / Graduate / 0485

Ph.d.

Como conseqüência do aumento da produção de cana nos últimos anos, ocorreu o aumento da quantidade de resíduos agroindustriais gerados a partir deste processo, sendo os principais a palha e o bagaço da cana-de-açúcar. O potencial de produção desses resíduos representa em média 14% da massa da cana processada. A celulose é o principal constituinte desses materiais e pode dar origem a outros materiais por meio de reações de derivatização. Entre os derivados de celulose mais importantes, estão os éteres e os ésteres de celulose. A celulose também pode ser fragmentada, a fim de se utilizar seu monômero formador, a glicose. O presente trabalho teve como objetivo extrair a celulose da palha e do bagaço de cana para utilizá-la na produção de dois derivados, o acetato de celulose e a carboximetilcelulose, além de fragmentá-la a glicose, visando a estudar a hidrólise enzimática necessária para produção de etanol celulósico. Para isso, foram testadas duas vias de obtenção da celulose, uma via denominada ácida e outra, denominada alcalina. Ao término de cada etapa das vias, os materiais produzidos foram caracterizados quimicamente com a finalidade de se elucidar o que acontecia em cada etapa. Ao final dos dois processos, o material obtido foi submetido às reações de acetilação e de carboximetilação. Os derivados de celulose foram caracterizados quanto aos seus graus de substituição e por FTIR. Com o acetato de celulose, foram produzidas membranas através de dois métodos distintos, a evaporação de solvente e a inversão de fases. Essas membranas foram caracterizadas fisicamente por MEV, DMA e teste de permeabilidade. Elas também foram testadas quanto à remoção de íons cobre em solução em estado estacionário. Todos os materiais obtidos nas duas vias testadas foram hidrolisados enzimaticamente utilizando-se as enzimas Celluclast 1.5L e ?-glicosidase. Em todas as vias estudadas e para os dois materiais analisados, foram obtidos como produtos finais, materiais com alto teor de celulose (em torno de 90%) e baixo de teor de lignina (menor que 4%), sendo a via alcalina considerada a de melhor desempenho, pois ocorreu menor perda de celulose nessa via do que na via ácida. Foram produzidos acetatos de celulose com grau de substituição 3, ou seja, triacetatos, ideais para a produção de membranas. Contudo, a presença da lignina, mesmo em pequena quantidade, não permitiu que fossem produzidas membranas com alta resistência mecânica. Em geral as membranas foram capazes de remover cerca de 15,0% dos íons cobres em uma solução aquosa. Dos dois métodos estudados, o de inversão de fases foi o que produziu as melhores membranas. Quanto à carboximetilcelulose, foram produzidas CMCs de diferentes características e mais uma vez a lignina interferiu no processo, quanto mais lignina possuía o material antes da produção de CMC, menor foi o grau de substituição obtido. Nas reações de hidrólise enzimática, quanto mais puro era o material em relação ao teor de celulose, maior foi a concentração de glicose no hidrolisado, sendo alcançadas concentrações em torno de 85,00%. / As a consequence of sugarcane increased production in recent years, there was an increased of residues generation from this process, being the straw and bagasse the main ones. The production potential of these wastes represents around 14% of the processed sugarcane mass. Cellulose is the main constituent of these materials and may give rise to other materials by derivatization reactions. Among the most important derivatives of cellulose, are ethers and esters of cellulose. Cellulose can also be fragmented in order to use its monomer, the glucose. The present work aims at extracting the cellulose from sugarcane straw and bagasse to use it in the production of two derivatives, cellulose acetate and carboxymethylcellulose and to fragment it into glucose for studying the enzymatic hydrolysis, which is a required step for ethanol cellulosic production. For this, it was tested two pathways of cellulose obtaining, the acid route and the alkaline route. At the end of each stage of the process, the materials were characterized chemically in order to elucidate what occurred in each step. After finishing both processes, the material was subjected to reactions of acetylation and carboxymethylation. The cellulose derivates were characterized physically for its degree of substitution and for FTIR. The cellulose acetate was utilized to produce membranes through two different methods, the solvent evaporation and the phase inversion. The membranes were characterized for MEV, DMA and permeability test. They were also tested for cooper ions removal. All materials produced at both pathways were hydrolyzed enzymatically for the enzymes Celluclast 1.5L and ?-glucosidase. In all cases, the final material presented high level of cellulose (about 90,0%) and low level of lignin (low than 4,0%). The alkaline route can be considered the one which achieved the best results, since it was in this pathway that the lowest cellulose lost occurred. The cellulose acetates presented a degree of substitution 3, in other words, they are triacetates, ideal for membrane production. Nevertheless, the presence of lignin, even in low amount, did not allow producing membranes with high mechanic resistance. In general, the membranes were able to remove about 15,0% of cooper ions in a aqueous solution. Between the methods carried out, the phase inversion was the one which produced membranes with the best properties. In relation to carboxymethylcellulose, it was obtained CMCs with different characteristics and, once more, the lignin interfered in the process. The more lignin content before CMC production, the less degree of substitution obtained. In the reactions of enzymatic hydrolysis, the highest cellulose purity proportioned the highest glucose concentrations in the hidrolysates, and it was reached conversion values around 85,00%.

Como conseqüência do aumento da produção de cana nos últimos anos, ocorreu o aumento da quantidade de resíduos agroindustriais gerados a partir deste processo, sendo os principais a palha e o bagaço da cana-de-açúcar. O potencial de produção desses resíduos representa em média 14% da massa da cana processada. A celulose é o principal constituinte desses materiais e pode dar origem a outros materiais por meio de reações de derivatização. Entre os derivados de celulose mais importantes, estão os éteres e os ésteres de celulose. A celulose também pode ser fragmentada, a fim de se utilizar seu monômero formador, a glicose. O presente trabalho teve como objetivo extrair a celulose da palha e do bagaço de cana para utilizá-la na produção de dois derivados, o acetato de celulose e a carboximetilcelulose, além de fragmentá-la a glicose, visando a estudar a hidrólise enzimática necessária para produção de etanol celulósico. Para isso, foram testadas duas vias de obtenção da celulose, uma via denominada ácida e outra, denominada alcalina. Ao término de cada etapa das vias, os materiais produzidos foram caracterizados quimicamente com a finalidade de se elucidar o que acontecia em cada etapa. Ao final dos dois processos, o material obtido foi submetido às reações de acetilação e de carboximetilação. Os derivados de celulose foram caracterizados quanto aos seus graus de substituição e por FTIR. Com o acetato de celulose, foram produzidas membranas através de dois métodos distintos, a evaporação de solvente e a inversão de fases. Essas membranas foram caracterizadas fisicamente por MEV, DMA e teste de permeabilidade. Elas também foram testadas quanto à remoção de íons cobre em solução em estado estacionário. Todos os materiais obtidos nas duas vias testadas foram hidrolisados enzimaticamente utilizando-se as enzimas Celluclast 1.5L e ?-glicosidase. Em todas as vias estudadas e para os dois materiais analisados, foram obtidos como produtos finais, materiais com alto teor de celulose (em torno de 90%) e baixo de teor de lignina (menor que 4%), sendo a via alcalina considerada a de melhor desempenho, pois ocorreu menor perda de celulose nessa via do que na via ácida. Foram produzidos acetatos de celulose com grau de substituição 3, ou seja, triacetatos, ideais para a produção de membranas. Contudo, a presença da lignina, mesmo em pequena quantidade, não permitiu que fossem produzidas membranas com alta resistência mecânica. Em geral as membranas foram capazes de remover cerca de 15,0% dos íons cobres em uma solução aquosa. Dos dois métodos estudados, o de inversão de fases foi o que produziu as melhores membranas. Quanto à carboximetilcelulose, foram produzidas CMCs de diferentes características e mais uma vez a lignina interferiu no processo, quanto mais lignina possuía o material antes da produção de CMC, menor foi o grau de substituição obtido. Nas reações de hidrólise enzimática, quanto mais puro era o material em relação ao teor de celulose, maior foi a concentração de glicose no hidrolisado, sendo alcançadas concentrações em torno de 85,00%. / As a consequence of sugarcane increased production in recent years, there was an increased of residues generation from this process, being the straw and bagasse the main ones. The production potential of these wastes represents around 14% of the processed sugarcane mass. Cellulose is the main constituent of these materials and may give rise to other materials by derivatization reactions. Among the most important derivatives of cellulose, are ethers and esters of cellulose. Cellulose can also be fragmented in order to use its monomer, the glucose. The present work aims at extracting the cellulose from sugarcane straw and bagasse to use it in the production of two derivatives, cellulose acetate and carboxymethylcellulose and to fragment it into glucose for studying the enzymatic hydrolysis, which is a required step for ethanol cellulosic production. For this, it was tested two pathways of cellulose obtaining, the acid route and the alkaline route. At the end of each stage of the process, the materials were characterized chemically in order to elucidate what occurred in each step. After finishing both processes, the material was subjected to reactions of acetylation and carboxymethylation. The cellulose derivates were characterized physically for its degree of substitution and for FTIR. The cellulose acetate was utilized to produce membranes through two different methods, the solvent evaporation and the phase inversion. The membranes were characterized for MEV, DMA and permeability test. They were also tested for cooper ions removal. All materials produced at both pathways were hydrolyzed enzymatically for the enzymes Celluclast 1.5L and ?-glucosidase. In all cases, the final material presented high level of cellulose (about 90,0%) and low level of lignin (low than 4,0%). The alkaline route can be considered the one which achieved the best results, since it was in this pathway that the lowest cellulose lost occurred. The cellulose acetates presented a degree of substitution 3, in other words, they are triacetates, ideal for membrane production. Nevertheless, the presence of lignin, even in low amount, did not allow producing membranes with high mechanic resistance. In general, the membranes were able to remove about 15,0% of cooper ions in a aqueous solution. Between the methods carried out, the phase inversion was the one which produced membranes with the best properties. In relation to carboxymethylcellulose, it was obtained CMCs with different characteristics and, once more, the lignin interfered in the process. The more lignin content before CMC production, the less degree of substitution obtained. In the reactions of enzymatic hydrolysis, the highest cellulose purity proportioned the highest glucose concentrations in the hidrolysates, and it was reached conversion values around 85,00%.

Different kinds of options and the possibilities of their use in international environment is the subject of this final thesis. At the beginning of thesis, history of options, their classification according to different kinds, and situation on the stock exchange market and OTC market are discussed. In the next part, the thesis speaks about the main option positions, more complicated option positions, warrants and interest rate option. Every single option is characterized in more detailed way along with the different examples of their use for financial risk management in the international trade or their use for more and more evolving speculation on the financial markets.

Various synthetic schemes were used to prepare a number of new amino-thio- and sulfonyladamantane compounds. By a nucleophilic substitution on 1-bromoadamantane, 1-(p-nitrophenylthio)adamantane was prepared from p-nitrothiophenol; the amino- and sulfonyl- derivatives of this compound were also prepared. Silver tosylate was used to generate the 1-adamantyl carbonium ion from 1-bromoadamantane in a synthetically useful procedure for preparing 1-adamantylamides from nitriles. Three 1-(1-adamantylcarbinyl)-2,5-dialkylpyrroles were prepared by Knorr-Paal reactions and reduced to the corresponding pyrrolidines. Thio- and aminomethyl 1-adamantyl ketones were prepared from methyl and bromomethyl 1-adamantyl ketones, respectively. Aliphatic and aromatic oxiranes were reacted with 1-aminoadamantane in a bomb at elevated temperatures to give several new 2-(1-adamantylamino)ethanol derivatives.

This thesis deals with investing into commodity assets through financial and commodity derivates. In the first section there are introduced single commodities and their historical price trends. There are further analysed relevant financial products, their positives and negatives. Practical section carries out an analyse of current state of the commodity market and makes the prediction of the future development. Finally there are mentioned different sorts of risk investors recommendations.

Given ongoing advocacy for the institutionalisation of derivatives trading in sub- Saharan Africa (SSA) as a convenient way for enhancing regional countries’ growth prospects, this study examines the impact of derivatives trading on the economy of South Africa, with reference to output growth and growth volatility, in order to illustrate the likely developmental impact that derivatives markets could ensue for SSA countries. The literature of the study essentially explores the possible ways of derivatives markets’ influence on economic growth, alongside the infrastructural requirements for ensuring well-functioning derivatives markets. While accounting for implied capital market development, the GMM estimation could not evidence a significant relationship between the existing derivatives exchange and real GDP growth using South Africa’s data. Similarly, a causal relationship from SAFEX’s trading volumes to GDP growth could not be inferred. However, the study shows evidence of the reducing effect of derivatives trading on growth volatility. / Business Management / M. Com. ( Business Management)

Given ongoing advocacy for the institutionalisation of derivatives trading in sub- Saharan Africa (SSA) as a convenient way for enhancing regional countries’ growth prospects, this study examines the impact of derivatives trading on the economy of South Africa, with reference to output growth and growth volatility, in order to illustrate the likely developmental impact that derivatives markets could ensue for SSA countries. The literature of the study essentially explores the possible ways of derivatives markets’ influence on economic growth, alongside the infrastructural requirements for ensuring well-functioning derivatives markets. While accounting for implied capital market development, the GMM estimation could not evidence a significant relationship between the existing derivatives exchange and real GDP growth using South Africa’s data. Similarly, a causal relationship from SAFEX’s trading volumes to GDP growth could not be inferred. However, the study shows evidence of the reducing effect of derivatives trading on growth volatility. / Business Management / M. Com. ( Business Management)