Les fortes tensions liées à l'approvisionnement en ressources minérales ont motivé de nombreuses recherches sur les substitutions innovantes et le recyclage. La biomasse riche en métaux produite par les techniques de phytoextraction s'est récemment avérée être une ressource pour la Chimie Verte. Cette biomasse permet de produire de nouveaux catalyseurs appelés « écocatalyseurs ». Ceux-ci permettent la production de nouvelles molécules, des meilleurs rendements en synthèse, une régio- et une chimio-sélectivité accrues… Ceci donne une valeur ajoutée potentielle et donc le possible développement d'une filière économique. Cette nouvelle approche pourrait motiver le développement de la phytoextraction, une technique considérée comme prometteuse, mais qui après 20 années de recherches n'a toujours pas trouvé de débouché crédible. Dans ce cadre, les haut lieux de la biodiversité « métallophyte », tels que la Nouvelle-Calédonie, ont leur importance pour évaluer l'approvisionnement en biomasse. En Nouvelle-Calédonie, l'ambitieuse et coûteuse restauration écologique de ces écosystèmes miniers très dégradés est mise en doute. Dans ce cas, le développement de la phytoextraction sur les carrières et verses à stériles pourrait apporter des revenus, tout en assurant une forme de réhabilitation. Cette thèse s'intéresse à la possibilité d'une filière en Nouvelle-Calédonie, de la plante au produit chimique en passant par le catalyseur. / Increasing pressure on mineral resources has drawn research efforts into innovative supply and recycling. Metal-rich biomass produced in phytoextraction proved an interesting starting-material for Green Chemistry. It allows the production of new catalysts, referred to as ‘ecocatalysts'. They provide the following benefits: access to new molecules, increased yields in chemicals production, increased regio- and chemo-selectivity… This results in potentially high added-value and possible development of a new economic outlet. This new approach to using metal-rich biomass could spur the development of phytoextraction, a technique considered promising for long, yet without credible economic applications. In this regard metallophyte biodiversity hotspots, such as New Caledonia are of particular interest to assess biomass supply. Ambitious and costly ecological restoration of the mining environment in New Caledonia is increasingly questioned. The development of phytoextraction on most degraded areas, e.g. quarries and wastes piles, to produce biomass for Ecocatalysis could provide revenues, while ensuring reclamation. This thesis looks into a possible outlet in New Caledonia, from plants to catalysts and final chemical products.

Orientador: Prof. Dr. Dalmo Mandelli / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2015. / Reações envolvendo a oxidação parcial de compostos organicos são importantes para um grande numero de processos industriais, incluindo a sintese de produtos de quimica fina. Com o objetivo de se obter rotas sustentaveis, e fundamental o desenvolvimento de catalisadores que sejam capazes de promover a sintese dos produtos desejados de forma eficiente, minimizando-se a geracao de substancias toxicas. Nesse contexto, o uso de H2O2 como agente oxidante tem ganhado importancia, pois sua decomposicao leva a formacao de agua e O2 como subprodutos. Recentemente tem surgido na literatura novas rotas sinteticas para a transformacao do glicerol (subproduto da industria do biodiesel) em outros produtos de maior valor agregado. O glicerol, por exemplo, pode ser facilmente desidratado para acetol (¿¿-hidroxiacetona), e este oxidado a outros produtos de interesse industrial. Assim, neste projeto foi estudada a oxidacao de acetol por catalise homogenea, usando o sistema FeCl3/H2O2, sendo encontrado acido acetico e acido formico como produtos principais, com formacao de 0,25 e 0,35 mol.L-1, respectivamente, a partir de 0,5 mol.L-1 de acetol apos 6h de reacao. Tambem foi estudada a evolucao de CO2 do meio reacional. Para tanto foi desenvolvida uma metodologia inedita, que faz uso do monitoramento por GC-MS dos sinais produzidos pelo CO2 e pelo argonio (usado como padrao interno) presentes no headspace da reacao. Essa metodologia permitiu determinar a formacao de 0,028 mol.L-1 de CO2 apos 4h em uma reacao tipica. Foi realizado um estudo cinetico da reacao avaliando-se o efeito das concentracao dos reagentes na velocidade inicial da reacao. Tambem foi estudada a participacao do O2 atmosferico na reacao por meio de testes utilizando 18O2 que indicam que o O2 participa da reacao desde seu inicio e que sua participacao inclui a incorporacao nos produtos formados. / Reactions involving the partial oxidation of organic compounds are important for a number of industrial processes, including the synthesis of fine chemicals. In order to achieve sustainable routes, it¿s essencial the development of basic catalysts that are capable of promoting the synthesis of the desired products efficiently, thus minimizing the generation of toxic substances. In this context, the use of H2O2 as an oxidizing agent has gained importance because its decomposition leads to the formation of water and O2 as byproducts. Recently it has appeared in the literature new synthetic routes for the transformation of glycerol (by-product of the biodiesel industry) in other products of higher value. Glycerol, for instance, may be readily dehydrated to acetol (á-hydroxyacetone), that can be oxidized to other products of industrial interest. Thus, in this project it was studied the acetol oxidation by homogeneous catalysis, using FeCl3/H2O2 system, being found that acetic acid and formic acid are the main products, forming 0.25 and 0.35 mol.L-1, respectively, from 0,5 mol.L-1 of acetol after 6h of reaction. It was also studied the evolution of CO2 from the reaction medium. For this purpose a novel method has been developed, which uses GC-MS for monitoring the signals produced by the CO2 and argon (used as internal standard) present in the headspace of the reaction. With this methodology it was possible to determine the formation of 0.028 mol.L-1 of CO2 after 4h on a reaction under typical conditions. A kinetic study of the reaction evaluating the effect of the reactants concentration on the initial rate of the reaction was carried out. It was also studied the participation of atmospheric O2 in the reaction by performing tests using 18O2, indicating that O2 participates in the reaction since its begining and that its participation includes the incorporation into the products formed.

Dans le contexte actuel du développement durable, l'industrie chimique, souvent montrée du doigt par les institutions et le grand public pour son impact négatif sur l'Homme et l'environnement, doit développer des voies de synthèse compétitives et plus éco-compatibles. La préparation d'époxydes à partir d'oléfines représente aujourd'hui un enjeu essentiel du point de vue de la production d'intermédiaires clés pour l'industrie chimique. Basé sur les nombreuses études publiées dans la littérature, ce travail de thèse a eu pour objectif d'étudier le potentiel des liquides ioniques, solvants novateurs aux propriétés uniques, et des ultrasons de puissance, méthode non conventionnelle d'activation, pour l'époxydation d'oléfines catalysée par des porphyrines métallées. Les protocoles expérimentaux de synthèse des liquides ioniques sélectionnés ont été améliorés au regard des principes de la chimie verte et évalués par des indicateurs spécifiques. Ensuite, les mécanismes des réactions d'époxydation ont été mis en évidence grâce à l'utilisation de porphyrines chirales et à l'étude des paramètres sonochimiques en milieu liquide ionique. Finalement, la stabilité des liquides ioniques sous irradiation ultrasonore a été étudiée ; ainsi, leurs produits de dégradation et leurs mécanismes de formation ont été identifiés. / In the current context of sustainable development, the chemical industry, often pointed at by the institutions and the general public for its negative impact on humans and the environment, needs to develop more competitive and more eco-friendly synthetic routes. The preparation of epoxides from olefins is today a critical issue in terms of production of key intermediates for the chemical industry. Based on numerous studies published in the literature, this PhD thesis has aimed at investigating the potential of ionic liquids, innovative solvents with unique properties, and power ultrasound, unconventional method of activation, for the epoxidation of olefins catalyzed by metalloporphyrins. The experimental protocols used for the synthesis of the selected ionic liquids have been improved according to the principles of green chemistry and evaluated by specific indicators. Then, the mechanisms of epoxidation reactions have been evidenced thanks to the use of chiral porphyrins and the study of sonochemical parameters in ionic liquids medium. Finally, the stability of ionic liquids under ultrasonic irradiation has been studied. Their degradation products and their formation mechanisms have been identified.

Submitted by ARIADNE MAGALHÃES CARNEIRO (ariadnemagcar@hotmail.com) on 2018-06-17T22:48:50Z No. of bitstreams: 1 Dissertação Ariadne Magalhães Carneiro Versão Corrigida 4.pdf: 2192618 bytes, checksum: 14dd0c6daab475134d8c57af4f4d517f (MD5) / Approved for entry into archive by Sulamita Selma C Colnago null (sulamita@btu.unesp.br) on 2018-06-18T20:32:00Z (GMT) No. of bitstreams: 1 carneiro_am_me_bot.pdf: 2192618 bytes, checksum: 14dd0c6daab475134d8c57af4f4d517f (MD5) / Made available in DSpace on 2018-06-18T20:32:00Z (GMT). No. of bitstreams: 1 carneiro_am_me_bot.pdf: 2192618 bytes, checksum: 14dd0c6daab475134d8c57af4f4d517f (MD5) Previous issue date: 2018-04-19 / Aproximadamente 3,7 x 109 toneladas de resíduos agrícolas são produzidos anualmente no mundo. Por ser uma das grandes potências agrícolas atualmente, grandes quantidades de resíduos agrícolas são geradas constantemente no Brasil. Uma das principais culturas produzidas no país é a soja. Além de seu uso na pecuária, utilizada na alimentação animal, assim como para alimentação humana, a soja desperta grande interesse do ponto de vista farmacológico, por ser uma das principais fontes de isoflavonas, uma forma de fitoestrogênio, sendo umas das espécies listadas na RENISUS. Este trabalho teve como objetivo investigar o perfil químico dos resíduos provenientes da cultura da soja (caules, folhas e vagens) por meio de uma abordagem analítica verde. Os extratos foram obtidos em triplicata por maceração dinâmica a 30 °C, com acetona e etanol, com e sem adição de ácido. O solvente acetonitrila foi utilizado como solvente de referência, pois é comumente empregado tanto para a extração como para a separação de isoflavonas presentes em grãos de soja. Os extratos foram analisados por cromatografia líquida de alta eficiência acoplada a um espectrofotômetro de untravioleta/visível (HPLC-PAD/UV) e a comparação da eficiência de extração entre os solventes testados foi feita com base em número total de picos, área total sob os picos e rendimento da extração. Os solventes verdes etanol e acetona mostraram-se mais eficientes do que o solvente de referência acetonitrila. Posteriormente, uma estratégia de identificação de compostos em mistura, baseada em dados obtidos por cromatografia líquida de alta eficiência acoplada a espectrometria de massas de alta resolução (HPLC-PDA/UV-ESI/TOF/MS) e em dados quimiotaxonômicos foi empregada. Foram identificadas as isoflavonas não glicosiladas daidzeína, genisteína e gliciteína, além da flavona apigenina, em resíduos de cultura de soja. Este trabalho sugere que isoflavonas e outros flavonóides poderiam ser obtidos de resíduos agrícolas da cultura de soja, amplamente disponíveis mundialmente, por meio de tecnologias verdes de extração e de análise. / Approximately 3.7 x 109 tonnes of agricultural waste is produced annually in the world. Because it is one of the great agricultural powers today, large amounts of agricultural residues are constantly generated in Brazil. One of the main crops produced in the country is soy. In addition to its use in livestock and human nutrition, the soybean awakes great interest from the pharmacological point of view, being one of the main sources of isoflavones, a form of phytoestrogen, being one of the species listed in RENISUS. The objective of this work was to investigate the chemical profile of residues from soybean (shoots, leaves and pods) using a green analytical approach. The extracts were obtained in triplicate by dynamic maceration at 30 ° C, with acetone and ethanol, with and without acid addition. The solvent acetonitrile was used as reference solvent, since it is commonly used both for the extraction and the separation of isoflavones present in soybean grains. The extracts were analyzed by high performance liquid chromatography coupled to an untraviolet/visible spectrophotometer (HPLC-PAD/UV) and the comparison of the extraction efficiency among the solvents tested was done based on total number of peaks, total area under peaks and extraction yield. The green solvents ethanol and acetone were more efficient than the reference solvent acetonitrile. Subsequently, a strategy for the identification of compounds in mixture, based on data obtained by high performance liquid chromatography coupled to high resolution mass spectrometry (HPLC-PDA/UV-ESI/TOF/MS) and chemotaxonomic data was used. The non-glycosylated isoflavones daidzein, genistein and glycitein, as well as flavone apigenin, were identified in soybean residue. This work suggests that isoflavones and other flavonoids could be obtained from soybean crop residues widely available worldwide through green extraction and analysis technologies.

Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-08T13:23:10Z No. of bitstreams: 1 arquivototal.pdf: 4925565 bytes, checksum: dc2866ffe0379ef9207b7bf8ed6689fa (MD5) / Made available in DSpace on 2017-06-08T13:23:10Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4925565 bytes, checksum: dc2866ffe0379ef9207b7bf8ed6689fa (MD5) Previous issue date: 2016-08-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In the current scientific scenario is increasing the need for new methodologies that meet both their main goal, which was developed as the expectations of a green chemistry, concerned about the environment and reducing impacts on it. Faced with such a need to adapt, have been developing alternative means to provide it. Recyclable catalysts; exchange of substrates; use of less toxic reagents; reactions without catalysts and/or free of solvents, are being proposed and boasting good results to your goals. Glimpsing a new reaction system for the Knoevenagel condensation, was developed a system without catalyst in a standard reaction between benzaldehyde and malononitrile, in order to meet your requirements best, and their conditions of operation. Among the tests of the solvent, which most outstanding in terms of increased speed of reaction by incidence of the solvent effect was a binary mixture of ethanol: water (3:7). It was apparent the need for heating, showing better reaction time in the range of 75-80° C, and 0,4 mL of binary mixture for each mole of substrates. Seen such conditions, the system was applied to a series of compounds with active methylene, aldehydes and ketones, in order to understand its Among the tests, the system has proven feasible to use malononitrile, cyanoesters, Meldrum's acid and Indandione with active methylene compounds as the Knoevenagel condensation; Malonitrile being the most reactive. The binary mixture was effectively applied in the Knoevenagel condensation reaction to a variety of structurally different aldehydes, where we observed a quick conversion with products of the 60 min to 1 min of time reactional and satisfactory income of 55 to 100%. For aliphatic ketones, the optimized system afforded reaction times of 5 to 6 hours, with satisfactory yields 74-75%. / No cenário científico atual é crescente a necessidade de novas metodologias que satisfaçam tanto seu objetivo principal, ao qual foi desenvolvido, quanto às expectativas de uma química verde, preocupada com o meio ambiente e redução dos impactos no mesmo. Frente a tal necessidade de adequação, vêm se desenvolvendo meios alternativos para supri-la. Catalisadores recicláveis; troca de substratos; utilização de reagentes menos tóxicos; reações sem catalisadores e/ou livres de solventes, vêm sendo propostos e ostentando bons resultados aos seus objetivos. Vislumbrando um novo sistema reacional para a Condensação de Knoevenagel, foi desenvolvido um sistema sem catalisador, em uma reação padrão entre benzaldeído e malononitrila, a fim de conhecer suas melhores condições de atuação. Dentre os testes do solvente, o que mais se destacou, em termos de aumento de velocidade de reação, por incidência de efeito do solvente, foi uma mistura binária de etanol:água (3:7). Foi perceptível a necessidade de aquecimento, apresentando melhor tempo reacional na faixa de 75-80°C, e de 0,4mL da mistura binária para cada mol de substratos. Visto tais condições, o sistema foi aplicado em uma série de compostos com metileno ativo, aldeídos e cetonas, a fim de compreender a extensão de sua aplicabilidade. Dentre os testes, o sistema se mostrou viável para a utilização de malononitrila, cianoésteres, ácido de meldrum e Indandiona como compostos com metileno ativo na condensação de Knoevenagel; sendo a Malonitrila a mais reativa. A mistura binária foi eficientemente aplicada na reação Knoevenagel para uma variedade de aldeídos estruturalmente distintos, onde observamos uma rápida conversão nos produtos com tempos reacionais de 1 a 60 min e rendimentos satisfatórios de 55 a 100%. Para as cetonas alifáticas, o sistema otimizado proporcionou tempos reacionais de 5 a 6 horas, com rendimentos satisfatórios de 74 a 75%.

Made available in DSpace on 2016-08-12T18:48:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-06-03. Added 1 bitstream(s) on 2016-08-12T18:50:58Z : No. of bitstreams: 1 000849809_20170603.pdf: 493191 bytes, checksum: e340cbcbe60c8fef82cacf91f8bf233b (MD5) Bitstreams deleted on 2017-06-09T11:52:05Z: 000849809_20170603.pdf,. Added 1 bitstream(s) on 2017-06-09T11:52:51Z : No. of bitstreams: 1 000849809.pdf: 1388233 bytes, checksum: f95f4c940c5c446bcf99c249e1ccbf5f (MD5) / A presença de elevadas concentrações de íons cobre(II) na aguardente a torna prejudicial à saúde humana e também é uma das causas que têm impedido o Brasil de atingir níveis maiores de exportação do produto. No Brasil, o limite máximo de cobre permitido em aguardente pelo MAPA (Ministério da Agricultura, Pecuária e Abastecimento) é de 5,00 mg.L-1, sendo que em países da União Européia e Estados Unidos esses limites são mais rigorosos, não permitindo mais que 1,00 e 2,00 mg.L-1, respectivamente. Assim, o presente trabalho propõe um novo método analítico simples, rápido, seguro, sensível, econômico, portátil, com baixo consumo de reagentes, geração de mínima quantidade de resíduos e ambientalmente mais amigável para determinação de íons cobre(II) em aguardente de cana-de-açúcar. Para processar a reação utilizou-se o agente cromogênico 1-(2-piridilazo)-2-naftol (PAN) e detecção por espectroscopia de reflectância difusa combinada com spot test. A reação de formação do complexo bis[1-(2-piridilazo)-2-naftalato]cobre(II) (Cu(PAN)2) foi realizada em papel de filtro, por meio da adição de 30 μL da solução do reagente cromogênico, com posterior secagem do papel e em seguida a adição de 30 μL da solução do analito. A máxima formação do produto ocorreu com concentração do agente cromogênico PAN de 0,12% m/v em etanol, concentração alcoólica de 40,0% v/v em pH 5,00 e 5 minutos de tempo de reação com detecção a 559 nm. Verificou-se que íons cádmio(II), cobalto(II), chumbo(II), ferro(III), manganês(II), níquel(II) e zinco(II) são interferentes na reação. Desta forma, empregou-se ácido malônico e tripolifosfato pentassódico (trifosfato de sódio) como agentes mascarantes a uma concentração de 0,25% m/v, reduzindo os efeitos de interferência para aproximadamente 2,0% e o deixando dentro dos limites toleráveis. Nas condições otimizadas de... / The presence of high concentrations of copper(II) ions in sugarcane spirits become harmful to human health and is also one of the causes that have prevented Brazil from achieving higher levels of exports of the product. The maximum limit of copper in spirit allowed by MAPA (Ministry of Agriculture, Livestock and Supply) is 5.00 mg.L-1, and in European Union countries and the United States these limits are more stringent, not allowing more than 1.00 e 2.00 mg.L-1 respectively. In light of the above, this work proposes a new analytical method that is simpler, fast, safe, sensitive, economical, portable, with low reagent consumption, generating minimal waste and environmentally more friendly for the determination of copper(II) ions in Brazilian sugarcane spirits. To process the reaction, the methodology used involved chromogenic agent 1-(2-pyridylazo)-2-naphthol (PAN) and detection by diffuse reflectance spectroscopy combined with spot test. The reaction of complex formation bis[1-(2-pyridylazo)-2-naphthalate]copper(II) (Cu(PAN)2) was carried out on a filter paper through the addition of 30 μL solution of the chromogenic reagent with subsequent drying of the paper, and 30 μL of analyte solution was added thereafter. The maximum product formation occurred at 559 nm with PAN chromogenic agent concentration of 0.12% m/v in ethanol, alcohol concentration of 40.0% v/v at pH 5.0 and 5 minute reaction time. Cadmium(II) ions, cobalt(II), lead(II), iron(III), manganese(II), nickel(II) and zinc(II) were found to interfere in the reaction. By virtue of that, malonic acid and pentasodium tripolyphosphate (sodium triphosphate) were used as masking agents at a concentration of 0.25% m/v, reducing the effects of interference at about 2.0% and leaving it within tolerable limits. In order to optimize the determination of copper(II) ions, an analytical curve was constructed and its equation is described by...

Le but de cette étude est d’évaluer l’utilisation de la chromatographie préparative dans le cadre de la conception d’un procédé de purification d’acides organiques. Les acides principalement étudiés sont les acides lactique et succinique. Ils sont produits par fermentation et utilisés depuis longtemps dans l’industrie comme additifs. Ils sont aussi identifiés comme des molécules plateformes très intéressantes pour le développement de la chimie verte, à partir de carbone renouvelable. En particulier, ils constituent des monomères pour l’industrie des bioplastiques. A la différence des utilisations historiques, ce type d’application requière des niveaux de pureté beaucoup plus importants. Ces puretés sont atteintes via des étapes supplémentaires d’extraction liquide-liquide, de distillation et/ou de cristallisation. Nous avons cherché à évaluer si la mise en œuvre de la chromatographie préparative pouvait permettre d’atteindre les spécifications requises. Pour cela, la chromatographie a été étudiée en détails en tant qu’opération unitaire, afin de mieux comprendre les mécanismes de séparation des composés étudiés et les paramètres de mise en œuvre. Deux types de résine ont été principalement utilisés, une cationique forte et une anionique forte. Dans un premier temps, l’étude thermodynamique de l’adsorption de trois acides organiques en solution pure a été réalisée. Elle a révélé un comportement très différent pour les deux résines : l’adsorption sur la résine cationique forte est assez linéaire alors que sur l’anionique forte, elle est fortement non linéaire et suit un modèle de Langmuir. L’influence de la vitesse sur la forme des pics et donc la dispersion pendant la séparation a ensuite été étudiée. Il a été montré que l’efficacité de la colonne diminue linéairement avec la vitesse d’élution, conformément au modèle de Van Deemter. Il a aussi été mis en évidence que la pente de cette droite est la même à l’échelle laboratoire et sur le pilote à une échelle dix fois plus grande. Elle peut ainsi permettre de prévoir l’évolution de l’efficacité de la colonne au changement d’échelle. Des solutions en mélange synthétiques et réels ont été étudiées, afin d’évaluer l’influence sur la séparation des paramètres opératoires, tels que la charge, la concentration de l’alimentation, le pH… 2 Sur la résine anionique, une première modélisation a été effectuée à partir de ces résultats expérimentaux. Elle a permis de mettre en évidence, qu’un mécanisme d’adsorption de type Langmuir ne suffit pas à expliquer la forme et la position des pics. Nous avons supposé qu’un mécanisme d’échange d’ions de la forme dissociée des acides organiques pourrait aussi entrer en jeu. Cet échange aurait un impact important sur la forme et la position des pics, bien que les acides organiques soient très majoritairement sous leur forme neutre. Les séparations mises en évidence à l’échelle laboratoire ont été validées à l’échelle pilote en chromatographie continue ISMB. Il a été montré que la résine anionique permet d’atteindre une plus grande pureté que la résine cationique avec une productivité similaire. Un procédé complet de purification a pu être testé avec de l’acide succinique, mettant en jeu une acidification par électrodialyse bipolaire, une concentration par osmose inverse, une séparation par chromatographie préparative sur résine anionique forte et une décoloration par nanofiltration. Le produit a ensuite été cristallisé afin de se comparer à un produit industriel. Le produit obtenu est proche des spécifications attendues et est plutôt meilleur que le produit industriel. Une étape supplémentaire d’échange d’ions aurait vraisemblablement permis d’obtenir des cristaux de grade polymère. Nous avons donc montré que la chromatographie a sa place dans un procédé de purification d’acides organiques, dans le but d’obtenir une très haute pureté. / The objective of this study is to evaluate the use of preparative chromatography in the context of the elaboration and optimization of an innovative purification process of organic acids from biotechnology. Lactic and succinic acids were mainly studied. They are produced by fermentation and used in industry as additive, for a long time. They are identified as promising building blocks for green chemistry development, from renewable carbon. In particular, they are monomers for bioplastic industry. Unlike historical utilizations, this new type of application requires much higher purity levels. Those purities are currently obtained by additional purification steps, like liquid-liquid extraction, distillation and/or crystallization. We tried to evaluate if the required specifications may be reached by the implementation of preparative chromatography. For this chromatography was studied in details as unitary operation, in order to better understand separation mechanisms of studied compounds and implementation parameters. Two resin types were mainly used, a strong cationic one and a strong anionic one. Firstly, thermodynamic study of the adsorption of three organic acids in pure solution was performed. It revealed very different performances for both resins: adsorption on strong cationic resin is quite linear, whereas on strong anionic one adsorption is strongly nonlinear and fits with Langmuir model. Elution velocity influence on peak shape and so on dispersion was then studied. Column efficiency decreases linearly with elution velocity, accordingly to Van Deemter model. It was shown that the line slope was identical at lab scale and on a pilot ten times bigger. Then it may be used to predict column efficiency evolution during scale-up. Mixing solutions from synthetic or real origin were studied, to evaluate operational parameter influence on the separation, as load, feed concentration, pH… On the strong anionic resin, a first modeling was developed for experimental results. It highlighted that Langmuir type adsorption mechanism is not able to explain peak shape and position. We supposed that an ion exchange mechanism with the organic acid dissociated part may happen. This exchange may have a significant impact on peak shape and position, even if organic acids are mainly in molecular form, because of a low work pH. 4 Separations established at lab scale were validated at pilot scale in continuous chromatography ISMB. It was demonstrated that the anionic resin allows to reach a higher productivity than the cationic one, with a similar productivity. A complete purification process was tested with succinic acid, using bipolar electrodialysis acidification, reverse osmosis concentration, preparative chromatography separation with a strong anionic resin and nanofiltration discoloration. Product was then crystallized, to be compared to an industrial product. Our crystals were close to waited specifications and relatively better than the industrial ones. An additional ion exchange step could have allows to reach polymer grade. We show that chromatography is useful in an organic acid purification process, in order to reach a very high purity.

O CO2 supercrítico (CO2-sc) é um bom solvente para substâncias apolares e pouco polares de baixa massa molecular. A fim de tornar este meio um melhor solvente para uma gama maior de substâncias, desenvolvemos 8 novos tensoativos, sendo seis derivados de açúcares (N-metil-D-glucamina, 2-D-Glucosamina e Sorbitano) e três derivados de óleos vegetais (linhaça e palma). Os tensoativos possuem como grupos CO2-fílicos, o acetato (peracetilados) ou o t-butil-glicidil-éter, e como grupo CO2-fóbico o dodecanoato, que pode proporcionar um ambiente \"apolar\" em eventuais agregados formados em CO2-sc. A solubilidade e o comportamento de fase destes novos tensoativos em CO2-sc foram investigados, mostrando-se bastante solúveis e apresentando pontos de névoa comparáveis a outros tensoativos fluorados (mais agressivos, do ponto de vista ambiental). A polaridade que estes tensoativos agregam ao meio foi verificada através de análises de solvatocromismo, utilizando o corante de Reichardt (Betaína-30) e fluorescência de pireno, as quais mostraram resultados bastante promissores, obtendo-se polaridades baixas e médias (similares a álcoois de cadeia média ou solventes clorados). / Supercritical CO2 (sc-CO2) is a good solvent for non-polar or almost non-polar substances with low molecular mass. In order to turn this medium into a better solvent for a wider range of substances, we developed 8 new surfactants, six of them sugar derivatives (N-methyl-D-glucamine, 2-D-Glucosamine and Sorbitan), and three of them vegetable oil derivatives (palm and linseed). The surfactants have either acetate (peracetylated) or t-butyl-glycidyl ether as CO2-philic groups, and as CO2-phobic group, dodecanoate, that can provide an \"apolar\" environment in aggregates that might be formed in sc-CO2. The solubility and phase behavior of these new surfactants in sc-CO2 were investigated, and they showed to be very soluble presenting low cloud pressures comparable to fluorinated surfactants (that are more aggressive from an environmental perspective). The polarity that these new surfactants brought to the medium was verified through the solvatochromic analysis, using the Reichardt\'s dye (Betaine-30) and pyrene fluorescence, which showed promising results, with polarities similar to medium chain alcohols or chlorinated solvents

A química limpa tem como principal objetivo o desenvolvimento e a implementação de processos e produtos químicos para reduzir ou eliminar o uso ou a geração de substâncias nocivas à saúde humana e ao meio ambiente. Neste trabalho, foram desenvolvidos procedimentos analíticos limpos para a determinação de nitrato e nitrito em águas naturais e para o tratamento dos resíduos gerados na determinação espectrofotométrica de nitrito e fenóis. Para tanto, foram exploradas as principais estratégias empregadas em química limpa: substituição dos reagentes tóxicos, minimização do consumo dos reagentes e dos resíduos gerados e tratamento desses resíduos. O procedimento analítico limpo para a determinação de nitrato em águas naturais foi baseado em medidas diretas no ultravioleta, após separação de nitrato dos interferentes utilizando um sistema de análises em fluxo com coluna de resina aniônica. O método desenvolvido emprega um único reagente (HClO4) em quantidades mínimas (18 µL/determinação) e permite a determinação de nitrato entre 0,50 e 25,0 mg L-1, sem interferência de ácido húmico, NO2-, PO43-, Cl-, SO42- e ferro(III) nas quantidades usuais em águas naturais. A freqüência de amostragem e o coeficiente de variação (n = 20) foram estimados em 17 determinações h-1 e 0,7%, respectivamente. Os resultados obtidos para amostras de águas de diferentes procedências foram concordantes com o método de referência (redução a nitrito por limalhas de cádmio cobreado seguida por reação de diazo-acoplamento) a nível de confiança de 95%. O tratamento do resíduo gerado na determinação de nitrito, empregando irradiação (UV) na presença do reagente de Fenton (80 mmol/L H2O2 e 1 mmol/L Fe2+), promoveu completa descoloração do resíduo com diminuição de ca. 87% na concentração de carbono orgânico total. A fotodegradação também foi aplicada no tratamento do resíduo gerado na determinação de fenóis totais com 4-aminoantipirina. A degradação ocorreu na presença de H2O2 e irradiação (UV). A completa supressão da absorção de radiação pela 4-aminoantipirina foi observada após 30 min de recirculação da solução no foto-reator, à vazão de 4 mL/min. O procedimento analítico para a determinação de nitrito foi baseado em sistema de análises em fluxo com multicomutação empregando mini-bombas solenóides para o gerenciamento das soluções. O sistema foi acoplado a um foto-reator para a degradação em linha dos resíduos gerados. O método desenvolvido minimiza as quantidades de reagentes (0,6 mg sulfanilamida e 0,03 mg N-naftil-etilenodiamina por determinação) e permite a determinação de nitrito entre 0,10 e 1,00 mg L-1 (r = 0,998) com sensibilidade comparável à alcançada no procedimento com adição contínua de reagentes. O limite de detecção (99,7% de confiança), coeficiente de variação (n = 20) e freqüência de amostragem foram estimados em 17 µg L-1, 2,6% e 80 determinações h-1, respectivamente. / Green chemistry has as principal objective the development and implementation of chemical processes and products to minimize or eliminate the use or generation of harmful substances to the human health and the environment. In this work, clean analytical procedures for determination of nitrate and nitrite in natural waters and for the treatment of wastes generated in the spectrophotometric determination of nitrite and phenol were developed. The principal strategies employed in green chemistry were explored to achieve these goals: replacement of the toxic reagents, minimization of reagent consumption and waste generation and waste treatment. The clean analytical procedure for nitrate determination in natural waters was based on the direct spectrophotometric measurement in the ultraviolet, after separation of nitrate from interfering species in a flow-injection system with an anion-exchange resin. The developed method employ only one reagent (HClO4) in minimum amount (18 µL/determination) and can be applied for nitrate determination within 0.50 and 25.0 mg L-1, without interference of humic acid, NO2-, PO43-, Cl-, SO42- and iron(III) in concentrations typically found in natural waters. The sampling rate and the coefficient of variation (n = 20) were estimated as 17 determinations per hour and 0.7%, respectively. Results obtained for natural water samples of different origin were in agreement with the reference method (reduction to nitrite by copperized cadmium filings followed by a diazo-coupling reaction) at the 95% confidence level. The treatment of the waste generated in nitrite determination employing UV irradiation in the presence of Fenton reagent (80 mmol/L H2O2 and 1 mmol/L Fe2+) caused the complete discoloration of the waste and reduced the total organic carbon concentration in 87%. The photodegradation was also applied for the treatment of the waste generated in the determination of total phenols with 4-aminoantipyrine. The degradation occurred in the presence of H2O2 and UV irradiation. Radiation absorption by 4-aminoantipyrine was completely suppressed after 30 min of treatment of solution in the recirculation mode at 4mL/min. The analytical procedure for nitrite determination was based on a flow system with multicommutation employing solenoid micro-pumps for the solution handling. The developed method minimizes the reagent amounts (0.6 mg sulfanilamide and 0.03 mg N-(1-Naphthyl)-ethylene-diamine per determination) and can be applied for nitrite determination within 0.10 and 1.00 mg L-1 (r = 0.998) with sensitivity comparable to the achieved in the procedure with continuous reagent addition. The detection limit (99.7% of confidence), coefficient of variation (n = 20) and sampling rate were estimated as 17 µg L-1, 2.6% and 80 determinations per hour, respectively.

O presente trabalho enfoca o desenvolvimento de procedimentos analíticos limpos através da extração e pré-concentração de íons metálicos em ponto nuvem para aumento de sensibilidade, melhoria de seletividade e substituição de solventes tóxicos. Cobre(II), ferro(II) e níquel(II) foram extraídos simultaneamente em digeridos de materiais vegetais, utilizando como agente extrator o Triton X-114, após formarem complexos hidrofóbicos com o 1,2-tiazolilazo-2-naftol (TAN). Os analitos foram determinados por espectrometria de absorção atômica com chama (Cu, Fe e Ni) ou por espectrofotometria de absorção molecular (Fe). A determinação de Cu e Ni por espectrofotometria de absorção molecular foi inviabilizada por interferências espectrais causadas pela formação de complexos com diversos íons metálicos encontrados nos digeridos dos materiais vegetais. Nas medidas por FAAS, os limites de detecção (99,7 % de confiança) foram estimados em 1,10 e 5 µg L-1 para cobre, ferro e níquel, respectivamente. Respostas lineares foram observadas para cobre e ferro na faixa de concentração de 25-200 µg L-1 e para o níquel entre 5 e 80 µg L-1 . O fator de enriquecimento foi estimado em 30 e a extração dos analitos foi quantitativa, de acordo com medidas efetuadas no sobrenadante após extração. Na determinação de ferro por espectrofotometria de absorção molecular, o limite de detecção foi estimado em 1 µg L-1 , com resposta linear entre 6 e 60 µg L-1 e fator de enriquecimento estimado em 20. Após digestão com ácidos diluídos em forno de microondas, o procedimento proposto foi aplicado à determinação dos analitos em digeridos de materiais de referência certificados, sendo os resultados concordantes com os valores certificados a nível de confiança de 95 %. O consumo de reagentes foi estimado em 50 mg Triton X-114 e 150 µg TAN por determinação. / This work is focused on the development of green analytical procedures for cloud-point extraction and concentration of metal ions, aiming increasing sensitivity, improving selectivity and avoiding the use of toxic solvents. Copper(II), iron(II) and nickel(II) were simultaneously extracted from plant materials digests, by using Triton X-114 as extracting agent, after formation of hydrophobic complexes with 1,2- tiazolylazo-2-naphthol (TAN). The analytes were determined by flame atomic absorption spectrometry (Cu, Fe and Ni) or by molecular absorption spectrophotometry (Fe). The determination of Cu and Ni by UV-vis spectrophotometry was hindered by spectral interferences caused by the formation of complexes with several metal ions in the sample digests. In the measurements by FAAS, the detection limits (99.7 % confidence level) were estimated as 1, 10 and 5 µg L-1 for copper, iron and nickel, respectively. Linear responses were observed in the 25-200 µg L-1 range for copper and iron and 5-80 µg L-1 for nickel. The enrichment factor was estimated as 30 and the extraction was quantitative, as evaluated by measurements in the supernatant solution after extraction. For iron determination by UV-vis spectrophotometry, the detection limit was estimated as 1 µg L-1 , with linear response within 6 and 60 µg L-1 and enrichment factor of 20. After digestion with diluted acids in microwave oven, the procedure was applied to the determination of the metals in reference materials and the results agreed with the certified values at the 95 % confidence level. The reagent consumption was estimated as 50 mg Triton X-114 and 150 µg TAN per determination.