A produção de biodiesel etílico é uma questão estratégica para a política energética nacional, uma vez que o Brasil é um dos maiores produtores de oleaginosas do mundo e o segundo maior produtor de etanol, álcool de origem renovável. Neste sentido, o presente trabalho buscou promover a transesterificação de óleos vegetais por etanol assistido por líquidos Iônicos sob diferentes fontes de aquecimento. O glicerol foi transformado em compostos de valor agregado e de interesse industrial. O mesmo foi modificado in situ após a reação de transesterificação gerando biodiesel aditivado pelos derivados da glicerina, conforme esquema 1. (Ver arquivo) / The production of ethyl biodiesel is a strategic issue for the national energy policy, because Brazil is one of the largest producers of oilseeds and the second largest producer of ethanol, a renewable alcohol. In this way, this work aimed to promote the transesterification of vegetable oils with ethanol assisted by ionic liquids under different heat sources. Glycerol was transformed into valuable compounds of industrial interest. It was also modified in situ after the transesterification reaction generating additive ethyl biodiesel, as shown below. (See file)

A produção de biodiesel etílico é uma questão estratégica para a política energética nacional, uma vez que o Brasil é um dos maiores produtores de oleaginosas do mundo e o segundo maior produtor de etanol, álcool de origem renovável. Neste sentido, o presente trabalho buscou promover a transesterificação de óleos vegetais por etanol assistido por líquidos Iônicos sob diferentes fontes de aquecimento. O glicerol foi transformado em compostos de valor agregado e de interesse industrial. O mesmo foi modificado in situ após a reação de transesterificação gerando biodiesel aditivado pelos derivados da glicerina, conforme esquema 1. (Ver arquivo) / The production of ethyl biodiesel is a strategic issue for the national energy policy, because Brazil is one of the largest producers of oilseeds and the second largest producer of ethanol, a renewable alcohol. In this way, this work aimed to promote the transesterification of vegetable oils with ethanol assisted by ionic liquids under different heat sources. Glycerol was transformed into valuable compounds of industrial interest. It was also modified in situ after the transesterification reaction generating additive ethyl biodiesel, as shown below. (See file)

A reação peroxioxalato está sendo amplamente utilizada para as mais variadas aplicações analíticas e bioanalíticas, porém, esta transformação é pouco estudada em meios aquosos, importantes principalmente para aplicações bioanalíticas. Neste trabalho foi estudada a reação de oxalato de bis(2,4,6-triclorofenila) (TCPO) com peróxido de hidrogênio (H2O2), em 1,2-dimetoxietano e em água, catalisada por 2,6-lutidina (2,6-dimetilpiridina). Observou-se que a reação ocorre com essa base agindo como um catalisador não-nucleofílico. A reação peroxioxalato foi realizada também em tampão borato onde a espécie reativa é a base conjugada do H2O2. A partir da dependência da constante de velocidade de decaimento da intensidade de emissão (kobs) com a concentração de peróxido de hidrogênio e do tampão borato se obtiveram evidências que a reação neste meio ocorre por catálise básica específica. Por último, a reação foi estudada em meio tampão borato contendo os líquidos iônicos (LIs) tetrafluoroborato de 1-butil-3-metilimidazólio (bmimBF4), cloreto de 1-alil-3- metilimidazólio (AmimCl) e acetato de 1-alil-3-metilimidazólio (AmimAc). A presença dos LIs no tampão resulta em um aumento dos rendimentos de formação de estados excitados singlete (Φs). Contrariamente, o aumento da concentração de sais comuns, como cloreto e acetato de tetrabutilamonio e NaCl, causou a diminuição dos valores dos rendimentos quânticos de quimiluminescência. As constantes de velocidade observadas aumentaram tanto com a concentração dos LIs quanto dos sais comuns. Os valores dos rendimentos quânticos de quimiexitação obtidos foram correlacionados com os parâmetros de viscosidade e polaridade das misturas. De maneira geral, foi mostrado neste trabalho que a reação peroxioxalato pode ser conduzida em meios essencialmente aquosos e a presença de LIs leva a um aumento do rendimento quântico de emissão, fatos importantes para potenciais aplicações analíticas. / The peroxyoxalate reaction is being widely used for a variety of analytical and bioanalytical applications, however, this transformation is very little studied in aqueous media, important mainly for bioanalytical applications. In this work was studied the reaction of bis(2,4,6-trichlorophenil) oxalate (TCPO) with hydrogen peroxide (H2O2) in 1,2-dimethoxyethane and water catalyzed by 2,6-lutidine (2,6-dimethylpyridine) was studied and it is observed that it occurs with this base acting as a non-nucleophilic catalyst. The peroxyoxalate reaction was also performed in aqueous borate buffer where the reactive species is the conjugate base of H2O2. Evidence is obtained that this reaction occurs through specific base catalysis from the dependence of the emission decay rate constant (kobs) with the hydrogen peroxide and borate buffer concentration. Finally, the reaction was studied in borate buffer media containing the ionic liquids (ILs) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4), 1-allyl-3-methylimidazolium chloride (AmimCl) and 1-allyl-3-methylimidazolium acetate (AmimAc). The presence of ILs in the buffer results in a concentration dependend increase of the yields of excited state formation (Φs). In contrast, the increase of the concentration of common salts, such as tetrabutylammonium chloride, tetrabutylammonium acetate and NaCl, caused a decrease in the emission quantum yields. The observed rate constants increased with both, the concentration of ILs and common salts. The chemiexcitation quantum yields values obtained were correlated with the viscosity and polarity parameters of the mixtures. In conclusion, it was shown in this work that the peroxyoxalate reaction can be conducted in essentially aqueous media and the presence of ILs leads to an increase in the emission quantum yields, important facts for potential analytical applications.

As zeólitas são amplamente utilizadas pela indústria em diferentes processos. Nos processos relacionados à conversão térmica do carvão, as zeólitas encontram aplicação, por exemplo, como suporte de catalisadores para a Síntese de Fischer-Tropsch, ou mesmo como adsorventes de efluentes líquidos ou de gases poluentes. No entanto, a microporosidade da zeólita limita a difusão dos produtos e dos reagentes ocasionando um transporte de massa lento e um longo tempo de residência, aumentando a possibilidade de reações secundárias, formação de coque e desativação do catalisador. Uma das maneiras de superar essas limitações é a introdução de um sistema secundário de poros, através da reestruturação da rede cristalina com modeladores de estruturas ou ataques químicos básicos e ácidos nas zeólitas de modo a formar materiais hierárquicos ou mesoporosos. Neste trabalho, foram investigadas três rotas para promover a mesoporosidade em zeólitas do tipo Y. Primeiramente foi realizada a síntese da zeólita hierárquica através da modificação com líquidos iônicos. O segundo método empregado foi o processo de dessilicação, utilizando hidróxido de sódio como base e, por último, a desaluminação com ácido oxálico. As zeólitas mesoporosas foram caracterizadas através de análises de área específica (BET), distribuição de tamanho de poros (BJH), difração de raios X (DRX) e redução à temperatura programada (TPR-H2). Dentre os métodos adotados, os resultados para DRX e BET mostraram que o tratamento de dessilicação destruiu a cristalinidade da zeólita, acarretando no abandono dessa rota de investigação. A síntese com líquido iônico se mostrou eficiente para a formação de mesoporos e, conforme a distribuição de tamanho de poros, seu sistema apresentou-se ordenado de maneira hierarquizada. A desaluminação não danificou a estrutura da zeólita, porém foi obtido um aumento pouco expressivo em seu número de mesoporos. A reação de esterificação foi utilizada, como modelo, para avaliar o efeito dos mesoporos sobre a atividade catalítica da reação. A reação de esterificação ocorreu a 70°C por 1 h, utilizando ácido acético e álcoois com diferentes tamanhos de moléculas. Em comparação à zeólita de partida (CBV720 - Zeolyst), a criação da mesoporosidade na zeólita através dos líquidos iônicos resultou em um aumentou na conversão de ácido acético para os álcoois etílico (em 17,65%), isopropílico (em 8,42%) e isobutílico (em 2%). Para a zeólita mesoporosa sintetizada por desaluminação, houve um acréscimo de 10,93% e 2,11% na conversão para os álcoois etílico e isopropílico, respectivamente. Os resultados mostraram que a presença de mesoporosidade influenciou positivamente o desempenho das zeólitas Y na reação modelo de esterificação, mostrando-se um excelente mecanismo a ser aplicado para facilitar o transporte de massa nos poros da zeólita, especialmente para a síntese feita com o emprego de líquidos iônicos. / Zeolites are widely used by industry in different processes. In processes related to the thermal conversion of coal, the zeolites find application, for example, as catalyst support for the Fischer-Tropsch Synthesis, or even as adsorbents of liquid effluents or pollutant gases. However, the small pore diameter of the zeolite limits the diffusion of the products and the reactants causing slow mass transport and a long residence time that increase the possibility of secondary reactions, coke formation and catalyst deactivation. One of the ways to overcome these limitations is the introduction of a secondary pore system by restructuring the crystal lattice with structural modellers or basic chemical and acidic attacks on zeolites to form hierarchical or mesoporous materials. In this work, three routes were investigated to promote mesoporosity in Y type zeolites. First, the hierarchical zeolite was synthesized through the modification with ionic liquids. The second method used was the desilication process, using sodium hydroxide as the base and, finally, the desalumination method with oxalic acid. The mesoporous zeolites were characterized by specific surface area analysis (BET), pore size distribution (BJH), X-ray diffraction (XRD) and temperature programmed reduction (TPR-H2). Among the methods adopted, the results for XRD and BET showed that the desilication treatment destroyed the crystallinity of the zeolite, leading to the abandonment of this research route. The synthesis with ionic liquid was efficient for the formation of mesopores and, according to the pore size distribution, its system was hierarchically ordered. The desalumination did not damage the zeolite structure, but a small increase in its number of mesopores was noted. The esterification reaction was used to evaluate the effect of mesopores on the catalytic activityof the reaction. The esterification reaction occurred at 70°C for 1 h using acetic acid and alcohols with different sizes of molecules. Compared to the starting zeolite (CBV720 - Zeolyst), the creation of mesoporosity in the zeolite through the ionic liquids resulted in an increase in the conversion of acetic acid for the reaction conducted with ethyl (17.65%), isopropyl (8.42%) and isobutyl alcohols (2%). For the mesoporous zeolite synthesized by desalumination, there was an increase of 10.93% and 2.11% in the conversion to the ethyl and isopropyl alcohols, respectively. The results showed that the presence of mesoporosity positively influenced the performance of the zeolites Y in the esterification model reaction, showing an excellent mechanism to be applied to facilitate the mass transport in the zeolite pores, especially for the synthesis made with the use of ionic liquids.

Heat transfer fluids are materials responsible for heat distribution, transfer and storage. Their significance is undeniable - many technological processes cannot be carried out without using heat transfer materials (for example due to overheating). These are usually mixtures of many compounds, for example glycols, silicones or water. Today's technologies constantly require more efficient, environmentally- and economically-friendly solutions for heat transfer applications. It is necessary to know the full physicochemical characteristics to design a new heat transfer fluid (mainly density, heat capacity, viscosity and thermal conductivity). Nanofluids (mixture of a basefluid and nanoparticles) were proposed as a solution for many industrial issues due to their enhanced thermophysical properties (i.e. thermal conductivity) than pure liquids. Moreover, these enhancements exhibit unusual features which make this group of materials interesting from molecular and industrial point of view. Ionic liquids, task specific materials with tuneable properties were repeatedly recommended as heat transfer fluids due to their specific properties (mainly low vapour pressure, wide liquidus range, or non-flammability) caused by the ionic structure. A very interesting material can be obtained by mixing ionic liquids and nanoparticles where specific properties of ionic liquids are preserved, and thermophysical properties are enhanced due to nanoparticles dispersion. In this work, we investigated ionic liquid - based nanofluids from the experimental and theoretical point of view, including imidazolium-, pyrrolidinium- and phosphonium-based ionic liquids with several different anions, and multiwalled carbon nanotubes, graphite, boron nitride and mesoporous carbon as nanoparticles, and also in mixtures with water. As a final result, we assessed the molecular recognition of the thermophysical properties enhancements in ionanofluids, developed the predictive models for physical properties, compared all investigated systems to commercial heat transfer fluids. The project was supported by King Faisal University (Saudi Arabia) through a research fund from the International Cooperation and Knowledge Exchange Administration department at KFU. Cytec are thanked for the generous donation of the trihexyl(tetradecyl)phosphonium chloride sample.

Ionic liquids are organic salts with room temperature melting points. Their unique physicochemical properties make them popular choices in the fields of tribology, energy storage and production, and extractions. Previous studies show that IL’s interfacial volume, extending some nanometers from an adjacent surface, is characterized by the self-assembly of IL molecules into ordered structures. This ordering imparts unique properties which often govern the properties of ILs and affect their application in the aforementioned areas. This thesis describes research conducted to understand the behaviors and interactions of ILs at interfaces, along with investigations of bulk IL structures and transitions in the presence of water. The findings reported will help the scientific community by giving insight into the physical and chemical processes surrounding IL behavior, allowing ILs’ physicochemical properties to be more accurately tailored, via judicious synthesis, to a desired application. Major findings of this work show that the ordered interfacial region may extend up to two orders of magnitude further from the interface than previously thought. Specifically, this thesis shows several examples of reversible IL self-assembly into long-range ordered films that extend up to ~ 2 μm from a surface. This is approximately twelve times the thickness of interfacial region previously reported. Temperature controlled studies on the bulk structure of an IL at its phase transition temperatures aid in understanding the structural arrangement of molecules in the bulk fluid as a function of temperature. Spectroscopic analyses of these bulk studies and the above interfacial systems showed no similarities, indicating that the self-assembled interfacial structures are, in fact, unique. Being hygroscopic in nature, water is the most common impurity found in ILs. Water can affect IL intermolecular forces and the resulting structures in bulk fluids as well as at the interface. One of the chapter of this thesis describes these interactions, and the variably hydrated IL structures for two classes of ILs via spectroscopic and electrochemical techniques. The outcomes of this thesis will aid the community in understanding interfacial and bulk structures of ILs, as well as influences of temperature and water on these structures. The description of extended IL structures provides valuable insights into new design principles for truly task-specific ILs.

This thesis focuses on liquid redox electrolytes in dye-sensitized solar cells (DSCs). A liquid redox electrolyte, as one of the key constituents in DSCs, typically consists of a redox mediator, additives and a solvent. This thesis work concerns all these three aspects of liquid electrolytes, aiming through fundamental insights to enhance the photovoltaic performances of liquid DSCs. Initial attention has been paid to the iodine concentration effects in ionic liquid (IL)-based electrolytes. It has been revealed that the higher iodine concentration required in IL-based electrolytes can be attributed to both triiodide mobility associated with the high viscosity of the IL, and chemical availability of triiodide. The concept of incompletely solvated ionic liquids (ISILs) has been introduced as a new type of electrolyte solvent for DSCs. It has been found that the photovoltaic performance of ISIL-based electrolytes can even rival that of organic solvent-based electrolytes. And most strikingly, ISIL-based electrolytes provide highly stable DSC devices under light-soaking conditions, as a result of the substantially lower vapor pressure of the ISIL system. A significant synergistic effect has been observed when both guanidinium thiocyanate and N-methylbenzimidazole are employed together in an IL-based electrolyte, exhibiting an optimal overall conversion efficiency. Tetrathiafulvalene (TTF) has been investigated as an organic iodine-free redox couple in electrolytes for DSCs. An unexpected worse performance has been observed for the TTF system, albeit it possesses a particularly attractive positive redox potential. An organic, iodine-free thiolate/disulfide system has also been adopted as a redox couple in electrolytes for organic DSCs. An impressive efficiency of 6.0% has successfully been achieved by using this thiolate/disulfide redox couple in combination with a poly (3, 4-ethylenedioxythiophene) (PEDOT) counter electrode material under full sunlight illumination (AM 1.5G, 100 mW/cm2). Such high efficiency can even rival that of its counterpart DSC using a state-of-the-art iodine-based electrolyte in the systems studied.The cation effects of lithium, sodium and guanidinium ions in liquid electrolytes for DSCs have been scrutinized. The selection of the type of cations has been found to exert quite different impacts on the conduction band edge (CB) of the TiO2 and also on the electron recombination kinetics, therefore resulting in different photovoltaic behavior. / QC 20120124

A multidisciplinary approach has been applied to the development of sustainable technologies for three industrially relevant projects. Reversible ionic liquids are novel carbon dioxide capture solvents. These non-aqueous silylamines efficiently capture carbon dioxide through chemical and physical absorption and release carbon dioxide with minimal addition of heat. The development of these capture agents aims to eliminate the need for a co-solvent, while minimizing energy loss and achieving solvent recyclability. Also presented is the use of carbon dioxide for amine protection during chemical syntheses. Amine protection is widely used in almost all sectors of chemical and pharmaceutical industries. The use of carbon dioxide as a reversible protecting group reduces solvent waste during protection and deprotection and improves the atom economy of existing processes. Sustainable chemistry has also been applied to the use of reversible ionic liquids as switchable surfactants for nanoparticle synthesis. The reversible ionic liquid system offers two significant advantages toward a more efficient synthesis and deposition of nanoparticles in that an additional surfactant is not required, and due to the reversible nature of the ionic liquids, a facile and waste-reduced deposition method exists.

A series of hydrophobic ionic liquids (ILs) have been employed to extract acetic acid (AcOH) or formaldehyde (HCHO) from aqueous solutions at atmosphere pressure. The ILs, mainly trihexyl(tetradecyl)phosphonium ([P6,6,6,14]+) carboxylate based ILs, were tested as a function of the anion chain length, which ranges from isobutyrate ([IB]-) to dodecanoate ([D]-). Most of these ILs show a large two-phase region and high extraction efficiency. Furthermore, tetraoctylphosphonium ([P8,8,8,8]+) and trihexyl(tetradecyl)ammonium ([N6,6,6,14]+) based ILs were also investigated to study the effect of the cation on extraction performance. Besides pure IL extraction, the mixture of IL and other chemicals, such as matched carboxylic acid, alkane and ester, were also investigated on extraction. The matched carboxylic acid could enhance the extraction performance and thus could be called ‘enhancer’. A balance point could be found for the ratio IL/enhancer to obtain a better extraction in each {H2O + AcOH + IL/enhancer} system, compared with the corresponding pure IL liquid-liquid equilibrium (LLE). Several ILs, including [P6,6,6,14]+ based ILs and imidazolium based ILs, were investigated on extraction of HCHO. Among these ILs, the imidazolium based ILs performed better than the [P6,6,6,14]+ based ILs in terms of two-phase region, hydrophobicity of IL-rich phase and partition coefficient/relative selectivity. The UNIQUAC method was employed to correlate the LLE data for pure IL systems. Some physical property data, such as density and viscosity, of ILs were correlated. The Joback group contribution method was used to predict the heat capacities of some ILs in this work. These correlations with low deviations made it possible for ILs to be further studied in Aspen process modelling.

As zeólitas são amplamente utilizadas pela indústria em diferentes processos. Nos processos relacionados à conversão térmica do carvão, as zeólitas encontram aplicação, por exemplo, como suporte de catalisadores para a Síntese de Fischer-Tropsch, ou mesmo como adsorventes de efluentes líquidos ou de gases poluentes. No entanto, a microporosidade da zeólita limita a difusão dos produtos e dos reagentes ocasionando um transporte de massa lento e um longo tempo de residência, aumentando a possibilidade de reações secundárias, formação de coque e desativação do catalisador. Uma das maneiras de superar essas limitações é a introdução de um sistema secundário de poros, através da reestruturação da rede cristalina com modeladores de estruturas ou ataques químicos básicos e ácidos nas zeólitas de modo a formar materiais hierárquicos ou mesoporosos. Neste trabalho, foram investigadas três rotas para promover a mesoporosidade em zeólitas do tipo Y. Primeiramente foi realizada a síntese da zeólita hierárquica através da modificação com líquidos iônicos. O segundo método empregado foi o processo de dessilicação, utilizando hidróxido de sódio como base e, por último, a desaluminação com ácido oxálico. As zeólitas mesoporosas foram caracterizadas através de análises de área específica (BET), distribuição de tamanho de poros (BJH), difração de raios X (DRX) e redução à temperatura programada (TPR-H2). Dentre os métodos adotados, os resultados para DRX e BET mostraram que o tratamento de dessilicação destruiu a cristalinidade da zeólita, acarretando no abandono dessa rota de investigação. A síntese com líquido iônico se mostrou eficiente para a formação de mesoporos e, conforme a distribuição de tamanho de poros, seu sistema apresentou-se ordenado de maneira hierarquizada. A desaluminação não danificou a estrutura da zeólita, porém foi obtido um aumento pouco expressivo em seu número de mesoporos. A reação de esterificação foi utilizada, como modelo, para avaliar o efeito dos mesoporos sobre a atividade catalítica da reação. A reação de esterificação ocorreu a 70°C por 1 h, utilizando ácido acético e álcoois com diferentes tamanhos de moléculas. Em comparação à zeólita de partida (CBV720 - Zeolyst), a criação da mesoporosidade na zeólita através dos líquidos iônicos resultou em um aumentou na conversão de ácido acético para os álcoois etílico (em 17,65%), isopropílico (em 8,42%) e isobutílico (em 2%). Para a zeólita mesoporosa sintetizada por desaluminação, houve um acréscimo de 10,93% e 2,11% na conversão para os álcoois etílico e isopropílico, respectivamente. Os resultados mostraram que a presença de mesoporosidade influenciou positivamente o desempenho das zeólitas Y na reação modelo de esterificação, mostrando-se um excelente mecanismo a ser aplicado para facilitar o transporte de massa nos poros da zeólita, especialmente para a síntese feita com o emprego de líquidos iônicos. / Zeolites are widely used by industry in different processes. In processes related to the thermal conversion of coal, the zeolites find application, for example, as catalyst support for the Fischer-Tropsch Synthesis, or even as adsorbents of liquid effluents or pollutant gases. However, the small pore diameter of the zeolite limits the diffusion of the products and the reactants causing slow mass transport and a long residence time that increase the possibility of secondary reactions, coke formation and catalyst deactivation. One of the ways to overcome these limitations is the introduction of a secondary pore system by restructuring the crystal lattice with structural modellers or basic chemical and acidic attacks on zeolites to form hierarchical or mesoporous materials. In this work, three routes were investigated to promote mesoporosity in Y type zeolites. First, the hierarchical zeolite was synthesized through the modification with ionic liquids. The second method used was the desilication process, using sodium hydroxide as the base and, finally, the desalumination method with oxalic acid. The mesoporous zeolites were characterized by specific surface area analysis (BET), pore size distribution (BJH), X-ray diffraction (XRD) and temperature programmed reduction (TPR-H2). Among the methods adopted, the results for XRD and BET showed that the desilication treatment destroyed the crystallinity of the zeolite, leading to the abandonment of this research route. The synthesis with ionic liquid was efficient for the formation of mesopores and, according to the pore size distribution, its system was hierarchically ordered. The desalumination did not damage the zeolite structure, but a small increase in its number of mesopores was noted. The esterification reaction was used to evaluate the effect of mesopores on the catalytic activityof the reaction. The esterification reaction occurred at 70°C for 1 h using acetic acid and alcohols with different sizes of molecules. Compared to the starting zeolite (CBV720 - Zeolyst), the creation of mesoporosity in the zeolite through the ionic liquids resulted in an increase in the conversion of acetic acid for the reaction conducted with ethyl (17.65%), isopropyl (8.42%) and isobutyl alcohols (2%). For the mesoporous zeolite synthesized by desalumination, there was an increase of 10.93% and 2.11% in the conversion to the ethyl and isopropyl alcohols, respectively. The results showed that the presence of mesoporosity positively influenced the performance of the zeolites Y in the esterification model reaction, showing an excellent mechanism to be applied to facilitate the mass transport in the zeolite pores, especially for the synthesis made with the use of ionic liquids.