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A series of imidazolium-based ionic liquids (ILs) were synthesised and used as single component and metal-free homogeneous catalysts to convert a renewable, inexpensive and non-toxic CO2 feedstock into useful products. The cycloaddition of carbon dioxide to epoxides to produce cyclic carbonate was evaluated. A detailed investigation was carried out on a variety of factors that affected the reactivity and selectivity, such as the catalyst structures (nature of cation and anion). The effect of reaction parameters (temperature, reaction time, CO2 uptake and catalyst amount) on the catalytic performance was also investigated in detail. High conversions and selectivities could be achieved under mild pressure condition (5 bar) using 1-n-butyl-3-methylimidazolium bromide. A synergetic effect of the acidic and basic sites as well as suitable hydrogen-bonding strength is considered crucial for the reaction to proceed smoothly. This protocol was found to be applicable to a disubstituted epoxide. Furthermore, the straightforward synthesis of cyclic carbonates by direct oxidative carboxylation from olefins was achieved using only 1-n-butyl-3-methylimidazolium bromide as a catalyst.

Neste trabalho analisou-se a degradação fotoeletroquímica de efluentes de curtume. Os experimentos de fotoeletrodegradação foram realizados por meio da incidência de radiação UV (lâmpada de mercúrio – 125 W), com aplicação de potencial controlado, com eletrodos de Ti/Pt e Ti/(70TiO2/30RuO2), em compartimento contendo o efluente. O tratamento fotoeletroquímico,com a utilização de eletrodos de Ti/(70TiO2/30RuO2), reduziu em 29,5% a coloração do efluente de curtume, e em 48,9% a matéria orgânica (DQO) presente no efluente estudado.Abstract The aim of this work was analyze the photoelectrochemical degradation of tannery wastewater. The photoelectrochemical experiments were accomplished by the incidence of the radiation of an UV lamp (a 125 W mercury lamp was used) under a controlled potential, evaluating the performance of Ti/Pt or a Ti/(70TiO2/30RuO2) electrodes, in a compartment containing the wastewater. In the experiments where the Ti/(70TiO2/30RuO2) electrode was utilized, a reduction of 29.5 % of the color and 48.9 % of the organic matter (DQO) was observed for the wastewater studied.

Neste trabalho foi realizado o estudo da degradação fotoquímica do corante vermelho bordeaux. O estudo objetivou a avaliação de tratamentos alternativos com vistas à aplicação de tecnologias limpas. Os experimentos de fotodegradação foram realizados através da incidência de radiação UV em um compartimento contendo o corante (solução). O tratamento fotoquímico reduziu em 99% a coloração e a concentração da solução contendo o corante vermelho bordeaux.This paper studied the photochemical degradation of food dye (red dye). The investigation aimed at the assessment of alternative treatments, focusing the use of clean technologies. The photochemical degradation experiments were performed in a compartment with UV radiation (mercury lamp - 250W). The photochemical treatment showed a 99% color and concentration reduction in the dye solution.

Green systems able to capture or fix CO(2) are becoming more important specially to reduce environmental impacts. In this work, the mechanism of insertion of CO(2) into styrene oxide (STYO) both in the absence and presence of the catalyst 1-butyl-3-methyl-imidazolium bromide (BMIm Br) was investigated through calculations based on density functional theory in the ωB97X-D level. Two different routes were considered and it was shown they are energetically available and compete against each other. For both routes, the rate-determinant step is the ring opening of STYO resulting from the nucleophilic attack of the Br(-) on the C atom from STYO and is associated mainly to the participation of the cation and the anion from the catalyst in the reaction. Reactive indices and noncovalent interaction analysis were used as a tool to investigate this reason. This work allowed a better comprehension of the underlying mechanism and the supplied data provide valuable support for the design of new more efficient ionic liquid catalyst.

O presente trabalho teve como proposta a construcao e a avaliacao de uma estacao de tratamento de efluentes em escala de bancada que utilizasse apenas processos fisicos, de modo que sua transposicao para uma escala maior nao acarretasse custos elevados. A avaliacao da eficiencia do tratamento foi feita atraves de medidas de parâmetros fisico-quimicos e analise de metais que foram comparados com os estabelecidos pela Legislacao. Verificou-se que a estacao de tratamento proposta mostrou-se eficiente na reducao dos parâmetros estudados, indicando a viabilidade de sua construcao em escala piloto.

Realizou-se um estudo do comportamento eletroquimico do Malathion em meio aquoso utilizando a tecnica de voltametria ciclica e potenciostatica. A corrente de pico apresentou dependencia linear com a concentracao da especie. Este resultado possibilita a aplicacao desta metodologia eletroanalitica na deteccao de Malathion em amostras ambientais. Os experimentos de fotodegradacao com lâmpada de mercurio foram eficientes na degradacao das solucoes de Malathion.

Neste trabalho foi realizado o estudo da degradação fotoquímica do corante vermelho bordeaux. O estudo objetivou a avaliação de tratamentos alternativos com vistas à aplicação de tecnologias limpas. Os experimentos de fotodegradação foram realizados através da incidência de radiação UV em um compartimento contendo o corante (solução). O tratamento fotoquímico reduziu em 99% a coloração e a concentração da solução contendo o corante vermelho bordeaux. This paper studied the photochemical degradation of food dye (red dye). The investigation aimed at the assessment of alternative treatments, focusing the use of clean technologies. The photochemical degradation experiments were performed in a compartment with UV radiation (mercury lamp - 250W). The photochemical treatment showed a 99% color and concentration reduction in the dye solution.