Made available in DSpace on 2016-06-02T20:37:48Z (GMT). No. of bitstreams: 1 5407.pdf: 1478791 bytes, checksum: 131adc16889c1ddfaa53704df84e9bfc (MD5) Previous issue date: 2013-06-21 / The present case study focused on the development, adaptation and analysis of the introduction of Green Chemistry in an experimental course in the first year of the chemistry teacher training Degree offered by the Chemistry Department of the Federal University of São Carlos (DQ-UFSCar), São Paulo State, Brazil. Modules for experimental lessons were proposed, based on the Science-Technology-Society (STS) teaching approach, and applied during one semester in a class of 30 undergraduate s (1st Semester 2011). The proposed didactic modules began with the presentation and discussion of documentaries with emphasis on controversial socioscientific issues, followed by an experiment of investigative character. All the conceptual topics included in these modules were originally part of the course syllabus, which were associated with the procedural and attitudinal contents emphasizing environmental and green chemistry education. The research corpus consisting of students textual production (response to questionnaires and reports) and transcript interviews (focal groups). The content analysis method was employed to describe and interpret the survey data. Also, the analysis of the experimental didactic modules using a holistic metric known as Green Star (GS) was carried out. Through the analysis of the results obtained by qualitative research in this case study, the didactic proposal enabled students to understand the contents in a complex context that included socioscientific issues, considering Green Chemistry as a mandatory demand for the initial teacher training. / O presente estudo teve como objetivo principal o desenvolvimento, adaptação e análise da inserção de práticas de laboratório com ênfase à Química Verde em uma disciplina de caráter experimental do primeiro ano do curso de Licenciatura em Química do Departamento de Química da Universidade Federal de São Carlos (DQ-UFSCar). Módulos para aulas experimentais foram propostos, baseados na abordagem de ensino CTS, e aplicados no decorrer de um semestre junto uma turma de 30 licenciandos do curso de interesse (1o. Semestre de 2011). A proposta de ensino estudada iniciou-se com uma aula expositiva dialogada (apresentação e discussão de reportagens ou documentários com ênfase às problemáticas sociocientíficas controversas), seguida pela realização do experimento de caráter investigativo, que compreendia os conteúdos conceituais inicialmente contidos na ementa da disciplina, associados aos conteúdos procedimentais e atitudinais voltados às questões ambientais e da Química Verde. O corpus da pesquisa foi constituído pela produção textual discente (resposta aos questionários e relatórios) e transcrição de entrevistas. A análise de conteúdo foi a metodologia empregada para descrever e interpretar os dados da pesquisa. Também neste trabalho realizou-se uma análise do grau verde das experiências aplicadas, usando como instrumento uma métrica holística, a Estrela Verde (EV). Por meio da análise dos resultados obtidos pela pesquisa qualitativa pautada em um estudo de caso foi possível observar que as experiências executadas possibilitaram aos estudantes compreender os conteúdos abordados e considerar a Química Verde como um eixo a ser adotado no ensino da Química.

Neste trabalho, fracionou-se e tratou-se a argila Brasgel. Esta argila foi pilarizada em vários estágios de facionamento e/ou tratamento com 5 meq de Al / g de argila: (i) Al-PILC, a argila passou por todos os estágios de fracionamento e tratamento (ARG), (ii) Al-PILCFe, a argila não passou pela etapa de retirada de Fe livre (ARGFe) e (iii) Al-PILCFe/silte, a argila não passou pelas etapas de retirada de silte e Fe livre (ARGFE/silte). Em análise por DRX observou-se que as Al-PILCs apresentaram uma distância basal maior que as argilas de partida. A análise textural indicou que as argilas Al-PILCs e ARGs são materiais mesoporosos, com poros do tipo fenda estreita e do tipo fenda, respectivamente. Além disso, as Al-PILCs apresentaram área superficial razoavelmente maior que as ARGs correspondentes. Outras análises feitas nas argilas foram: teor de Si, Fe e Al; CTC; FTIR; TGA e TGD. As argilas Brasgel pilarizadas foram usadas como catalisador na reação de isomerização do óxido de estireno em hexano sob refluxo. A reação foi seletiva na formação de fenilacetaldeído. As argilas Al-PILCFe e Al-PILCFe/silte apresentaram melhor desempenho catalítico (100 % de conversão em 20 min de reação). Assim, as argilas Brasgel pilarizadas se apresentaram como uma Tecnologia Limpa na reação de isomerização do óxido de estireno ao fenilacetaldeído. Palavras-chave: Desenvolvimento Sustentável. Tecnologia Limpa. Química Verde. Argilas Pilarizadas. Isomerização de Epóxidos. / This work, the Brasgel clay was fractionated and treated. The clay was pillared in several stages of fractionation and / or treatment with Al 5 meq / g of clay: (i) Al- PILC, the clay has passed through all stages of treatment and fractionation (ARG), (ii) Al-PILCFe, the clay would not pass the step of removal of free Fe (ARGFe) and (iii) Al-PILCFe/silt, clay has not gone through the steps of removing silt and free Fe (ARGFE/silt). XRD analysis showed that the Al-PILCs showed a basal spacing greater than the starting clays. The textural analysis indicated that the Al-PILCs and ARGs are mesoporous materials, with pore narrow slit type and slit type, respectively. Moreover, the Al-PILCs showed reasonable surface area greater than the corresponding ARGs. Other analyzes were made on clays: the content of Si, Fe and Al; CEC, FTIR, TGA and TGD. Brasgel pillared clays have been used as catalyst in the isomerization reaction of the styrene oxide in refluxing. The reaction was selective for the formation of phenylacetaldehyde. Al-PILCFe and Al-PILCFe/silt clays showed better catalytic performance (100% conversion in 20 min of reaction). Thus, the pillared clays Brasgel presented as a Clean Technology in the isomerization reaction of styrene oxide to phenylacetaldehyde. Keywords: Sustainable Development. Clean Technology. Green Chemistry. Pillared Clays. Isomerization of Epoxides.

This thesis describes the synthesis and characterisation of novel mono and dinuclear homogenous [Zn(II)] and [In(III)] metal complexes. Their applications as catalysts for CO₂/epoxide or epoxide/anhydride ring opening copolymerisation and lactide ring opening polymerisation to generate polycarbonates and polyesters, respectively, are also reported. Chapter 3 reports the first indium phosphasalen catalysts for CO₂/cyclohexene oxide ring opening copolymerization. The catalysts are active at 1 bar pressure of CO₂ and are most effective without any co-catalyst. It is also possible to use the complexes to isolate and characterise the key intermediates in the catalytic cycle. Kinetic and spectroscopic analyses show that polymerisation proceeds via a rare cis-mononuclear coordination- insertion mechanism. Chapter 4 describes a series of mono and dinuclear zinc macrocycle catalysts with very high activities for the racemic lactide ring opening polymerisation. In most cases, the dinuclear zinc catalysts significantly out-perform the mono-zinc homologue. In addition, kinetic and spectroscopic investigations suggest a role for the ligand conformation in mediating rate. The catalysts perform very well under immortal conditions and operate at low catalyst loading, whilst conserving high activities. Chapter 5 presents four dinuclear zinc acetate salen catalysts for the ring opening copolymerisation of CO₂/cyclohexene oxide and phthalic anhydride/cyclohexene oxide. The catalysts show moderate activities for CO₂/epoxide copolymerisation but are highly active for epoxide/anhydride copolymerisation. Structure/activity relationship studies reveal that the more flexible and electron donating ligand displays the highest activity. Poly(ester-b-carbonate)s are also afforded using the most active catalyst in terpolymerisations of anhydride/epoxide/CO₂.

Magister Scientiae - MSc (Physics) / Zinc oxide (ZnO) is a wide and direct semiconductor with a wurtzite crystal structure. Its multifunctionality as the ideal candidate in applications such as blue-UV light emitting diodes, transparent conducting oxide, selective gas sensor and efficient catalyst support among others, has attracted a significant interest worldwide. Nano-scaled ZnO has been synthesized in a plethora of shapes. A rich variety of physical and chemical methodologies have been used in the synthesis of undoped or doped ZnO. However, such methods either necessitate relatively high vacuum infrastructures, elevated temperatures, or the use of toxic reagents. The "green chemistry" synthesis of metal oxide nanoparticles which is based on using natural plant extract as an effective 'reducing agent' of metal precursor, has been reported to be a cleaner and environment-friendly alternative to the physical and chemical methods. The thesis is based on the synthesis and the main physical properties of pure ZnO nanoparticles synthesized by a completely green chemistry process using the natural extract of Aspalathus Linearis to bio-reduce the zinc acetate precursor. The obtained ZnO nanopowdered samples were annealed at different temperatures from 300 °C to 600 °C. The samples were characterized using Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Transmission Electron Microscopy, X-ray Diffraction, Differential Scanning Calorimetry, Thermogravimetric Analysis and Fourier Transform Infrared. Highly pure quasi-spherical ZnO nanoparticles with an average crystallite size of 24.6 nm (at 300 °C), 27.2 nm (at 400 °C), 27.6 nm (at 500 °C), and 28.5 nm (at 600 °C) were found. The results also showed that the average crystallite size increased with an increase in annealing temperature. It was successfully demonstrated that the natural plant extract of Aspalathus Linearis can be used in the bio-reduction of zinc acetate dihydrate to prepare highly pure ZnO nanoparticles.

Les ressources minérales s’épuisent inexorablement, les minerais riches sont de plus en plus difficilement accessibles, et le traitement des minerais implique d’importants impacts environnementaux. En Nouvelle-Calédonie, l’extraction du nickel nécessite la destruction de l’horizon fertile supérieur des sols, et les mines se présentent comme des carrières à ciel ouvert, soumises à l’érosion et menaçant la biodiversité du territoire. Bien que l’exploitation du nickel soit au cœur de l’économie locale, la réhabilitation écologique des sites miniers, et la réintroduction durable d’un couvert végétal sont une nécessité.Le laboratoire ChimEco a démontré qu’il était possible de revégétaliser les sites miniers en réintroduisant des espèces végétales pionnières, résistantes et accumulatrices de manganèse. Ces plantes accumulatrices sont capables d’extraire le manganèse naturellement présent dans le sol et de l’accumuler dans leurs parties aériennes : on parle de phytoextraction. Le laboratoire ChimEco propose en outre une valorisation scientifique et à terme économique des efforts de réhabilitation engagés sur le terrain. En effet, à partir de la biomasse riche en manganèse des plantes accumulatrices, le laboratoire ChimEco a développé un procédé innovant de recyclage des éléments métalliques d’origine végétale en catalyseurs polymétalliques pour la chimie. Il s’agit de l’Ecocatalyse. Ces écocatalyseurs riches en Mn, notés Eco-Mn, ont montré une activité catalytique intéressante dans plusieurs synthèses organiques.Les résultats obtenus en écologie et en chimie par le laboratoire ChimEco prouvent la nécessité d’étudier finement la structure des écocatalyseurs en les considérant comme des matériaux innovants, afin de comprendre et d’améliorer leur activité en synthèse organique, et d’exploiter au mieux les possibilités du procédé. C’est précisément dans ce contexte que s’inscrivent ces travaux de thèse.Plusieurs techniques d’analyse ont été utilisées. Les analyses ICP-MS ont permis de déterminer la composition élémentaire des Eco-Mn. La DRX a permis de mettre en évidence la présence de sels mixtes originaux tels que K3NaMnCl6 sous forme cristalline dans les Eco-Mn. Enfin l’absorption des rayons X a permis de déterminer la nature des espèces présentes dans les catalyseurs, ainsi que le degré d’oxydation du manganèse et du fer. En outre, l’étude du réarrangement d’un acétal cyclique, ainsi que le suivi de la désorption de la pyridine à la surface des Eco-Mn, ont été utilisés pour étudier les propriétés acides des écocatalyseurs. Ces analyses ont permis de répondre à deux objectifs précis : d’une part déterminer la nature des complexes qui composent les Eco-Mn, et d’autre part, mieux comprendre les propriétés physico-chimiques de ces catalyseurs, leur degré d’oxydation et leurs propriétés acides. Ces analyses ont également permis de mieux appréhender les deux étapes du procédé de synthèse des Eco-Mn. Enfin, des catalyseurs synthétiques et témoins ont également été produits et étudiés dans les mêmes conditions d’analyse que les Eco-Mn, dans le but de déterminer si les Eco-Mn ont une spécificité et une empreinte végétale. / Mineral resources are running out, ores are hardly accessible, and ores processing damage the environment. In New-Caledonia, nickel ores mining requires to remove all the upper layers of the ground, leading to open-cast mines subjected to erosion, which threaten the environment and the biodiversity of the archipelago. Although mining ores exploitation is important for the economy of New-Caledonia, the ecological remediation of mining areas through the restoration of a vegetation cover, are necessary.ChimEco laboratory has demonstrated that it is possible to reintroduce pioneering endemic plant species, which are resistant to climate conditions and accumulate manganese, to restore New-Caledonian mining sites. These accumulating plants extract Mn from the ground to their aerial parts: it is called phytoextraction. Besides, ChimEco laboratory puts forward a new scientific and economic valorisation of phytoremediation efforts in New-Caledonia. Indeed, an innovative process has been developed to recycle metallic elements from manganese enriched biomass into innovative and polymetallic catalysts for organic synthesis. This new process is called Ecocatalysis. Ecocatalysts enriched in manganese, Eco-Mn, have demonstrated interesting and promising catalytic activities in several reactions.Regarding the good results achieved by ChimEco in ecology and in chemistry with accumulating plants and resulting Eco-Mn, it is necessary to better and precisely characterise Eco-Mn catalysts, by considering them as innovative materials, in order to understand and foresee their catalytic activity. This PhD work belongs within this context.Several analyses have been performed to characterise Eco-Mn catalysts. First, ICP-MS enables to identify metallic composition of Eco-Mn. Besides, XRD analyses highlight the presence of complex crystallized manganese salts, like K3NaMnCl6. Finally, X-ray absorption spectroscopy enables us to study the nature of manganese species which compose Eco-Mn catalysts, and to understand the oxidation states of Mn and Fe. Moreover, acid properties of Eco-Mn were demonstrated thanks to the study of a cyclic acetal rearrangement and infra-red spectroscopy of adsorbed pyridine. All these analyses were performed in order to determine first the composition of Eco-Mn catalysts, and secondly to highlight their physico-chemical properties, their oxidation state and their acid properties. Furthermore, this study also enable us to better understand the different steps of the ecocatalysts production process. Finally, synthetic catalysts were also produced and analysed in the same conditions as Eco-Mn, in order to bring out the specificities of Eco-Mn.

Disponibiliza??o do conte?do parcial, conforme Termo de Autoriza??o no trabalho. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2016-12-21T19:05:57Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wbiratan_cesar_macedo_oliveira_parcial.pdf: 128173 bytes, checksum: 9c9067430cf3b7ef9b7952182484b258 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-01-31T14:19:01Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wbiratan_cesar_macedo_oliveira_parcial.pdf: 128173 bytes, checksum: 9c9067430cf3b7ef9b7952182484b258 (MD5) / Made available in DSpace on 2017-01-31T14:19:01Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) wbiratan_cesar_macedo_oliveira_parcial.pdf: 128173 bytes, checksum: 9c9067430cf3b7ef9b7952182484b258 (MD5) Previous issue date: 2016 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG) / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Neste trabalho foi estudado o comportamento de extra??o do lant?nio em sistemas aquosos bif?sicos (SAB) e foi desenvolvido um novo m?todo hidrometal?rgico ambientalmente seguro para a extra??o seletiva de La a partir de lixiviado de baterias NiMH. O comportamento de extra??o do La foi avaliado verificando a influ?ncia dos seguintes par?metros: presen?a e concentra??o de diversos agentes extratantes (Alaranjado de xilenol, 1-(2-piridilazo)-2-naftol, Ditizona, 8-hidroxiquinolina, e 1,10-fenantrolina); pH (3,00, 6,00 e 9,00); eletr?lito (Li2SO4, Na2SO4, MgSO4, Na2C4H4O6 e Na3C6H5O7 ) e pol?mero (L64 e PEO1500) formadores do sistema. A efici?ncia de recupera??o foi avaliada atrav?s da an?lise da porcentagem de extra??o (% E) e as melhores condi??es de extra??o do analito foram obtidas no SAB formado por PEO1500 + Li2SO4 + H2O, pH = 6,00; empregando o extratante 1,10-fenantrolina, atingindo um valor m?ximo de %E = 74,1 %. Na sequencia o m?todo foi aplicado a um lixiviado de bateria NiMH. Os terras raras foram precipitados mediante ajuste de pH (2,50) e posteriormente solubilizado em solu??o de H2SO4 0,1 M. Ap?s 3 etapas sucessivas de extra??o foram obtidos altos valores de fator de separa??o (S) entre o analito e os concomitantes met?licos (SLa,Co = 6.3 x 103, SLa,Ni= 2,55 x 104, SLa,Fe= 1,15 x 103 and SLa,Ce= 30,9). Al?m disso, foi realizado um ensaio de stripping no qual 88,5% de La, em uma ?nica etapa, foi redisponibilizado sob a forma i?nica na FI para uma poss?vel etapa posterior de eletrodeposi??o. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / In this work was investigated the extraction behavior of lanthanum in the aqueous two-phase system (ATPS) and new environmentally safe hydrometallurgical method was developed for the selective extraction of La from NiMH battery leachate. The extraction behavior of La was evaluated verifying the influence of the following parameters on the metals extraction: presence and concentration of the several extractants 1-(2-piridil-azo)-2-naphtol, dithizone, 8-hydroxyquinoline, 1-10 phenanthroline and xylenol oragne; pH (3.00, 6.00 and 9.0); ATPS-forming electrolyte ((Li2SO4, Na2SO4, MgSO4, Na2C4H4O6 e Na3C6H5O7); ATPS-forming polymer (L64 or PEO1500). The recovery efficiency was evaluated through analyzing the extraction percentage (%E) and the best conditions for analyte extraction were achieved for the PEO1500 + Li2SO4 ATPS, pH = 6.00, using 1-10 phenanthroline as extractant agente (%E = 74,1 %). In the following section, the method was applied to a real NiMH battery leachate. The rare earths were precipitated by pH adjustment (2.50), which was solubilized in 0,1 M H2SO4 solution. After 3 steps of successive extractions it was possible to obtain high separation factor (S) values between the analyte and mettalic concomitant (SLa,Co = 6.3 x 103, SLa,Ni = 2,55 x 104, SLa,Fe = 1,15 x 103 and SLa,Ce = 30,9). Moreover, a stripping assay was carried out and after one single step, 88.5% of lanthanum was available to a possible electro winning step.

Cette thèse porte sur la modélisation multi-échelle des réactions en catalyse hétérogène de polyols sur une surface de platine 111, en phase aqueuse. Ce travail s’inscrit dans l’utilisation de la biomasse lignocellulosique. Les réseaux réactionnels issus du traitement de cette matière première sont très grands en taille, et en complexité. D’autre part, la nature même des molécules la composant impose une chimie en phase aqueuse. Il n’est donc pas possible de cartographier l’ensemble des ces chemins réactionnels avec des méthodes de calcul ab initio, tant les conditions aqueuses et le grand nombre de simulations que cela impliquerai demanderaient d’effort computationnel. Le changement d’échelle de simulation peut répondre à ce problème. Nous avons ainsi développé un modèle d’additivité par groupes permettant la prédiction des propriétés thermodynamiques de réactions de polyols sur platine 111 en phase aqueuse, à partir de la seule structure topologique des réactifs. Ce modèle a été construit sur un jeu de données issus de calculs en théorie de la fonctionnelle de la densité. Nous avons également étudié la cinétique de réactions de mêmes types, afin d’en prédire l’énergie d’activation à partir de leur thermodynamique. En parallèle, nous avons décrit l’influence de la micro-solvatation par rapport à un modèle de solvant implicite sur la réactivité d’alcools sur platine 111, ce qui couplé avec le modèle d’additivité par groupe permettra des simulations micro cinétiques complètes. Enfin, la réactivité des isomères du butanediol a été traitée afin de comprendre l’influence de l’espacement des fonctions alcools sur la réactivité d’un polyol. / This thesis focuses on multi scale simulations heterogeneous catalysis reactions of polyols on platinum (111) in aqueous phase. This work is about lignocellulosic biomass valorisation. The reaction networks raising from these materials are extremely large and complex. Also, the properties of the molecules forming this biomass make aqueous conditions mandatory. Ab initio methods as we know them forbids us to treat entire networks at the finest calculation level, the computational cost would be way beyond feasibility. Changing the simulation scale can tackle this problem. Thus, we developed a group additivity model assessing for thermochemical properties of polyols at a platinum (111) surface under aqueous conditions, with a topology as the only input. This model was built upon a density functional theory set. Kinetics of reactions was also covered, and the difference in terms of impact was investigated between implicit and explicit micro solvation models, in order to predict reaction barriers. The two models might be used together in order to feed a micro kinetic simulation, allowing a drastic decrease of reaction networks complexity. Finally, the influence on reactivity and selectivity, of hydroxyl groups on butanediol isomers was investigated.

Neste trabalho, fracionou-se e tratou-se a argila Brasgel. Esta argila foi pilarizada em vários estágios de facionamento e/ou tratamento com 5 meq de Al / g de argila: (i) Al-PILC, a argila passou por todos os estágios de fracionamento e tratamento (ARG), (ii) Al-PILCFe, a argila não passou pela etapa de retirada de Fe livre (ARGFe) e (iii) Al-PILCFe/silte, a argila não passou pelas etapas de retirada de silte e Fe livre (ARGFE/silte). Em análise por DRX observou-se que as Al-PILCs apresentaram uma distância basal maior que as argilas de partida. A análise textural indicou que as argilas Al-PILCs e ARGs são materiais mesoporosos, com poros do tipo fenda estreita e do tipo fenda, respectivamente. Além disso, as Al-PILCs apresentaram área superficial razoavelmente maior que as ARGs correspondentes. Outras análises feitas nas argilas foram: teor de Si, Fe e Al; CTC; FTIR; TGA e TGD. As argilas Brasgel pilarizadas foram usadas como catalisador na reação de isomerização do óxido de estireno em hexano sob refluxo. A reação foi seletiva na formação de fenilacetaldeído. As argilas Al-PILCFe e Al-PILCFe/silte apresentaram melhor desempenho catalítico (100 % de conversão em 20 min de reação). Assim, as argilas Brasgel pilarizadas se apresentaram como uma Tecnologia Limpa na reação de isomerização do óxido de estireno ao fenilacetaldeído. Palavras-chave: Desenvolvimento Sustentável. Tecnologia Limpa. Química Verde. Argilas Pilarizadas. Isomerização de Epóxidos. / This work, the Brasgel clay was fractionated and treated. The clay was pillared in several stages of fractionation and / or treatment with Al 5 meq / g of clay: (i) Al- PILC, the clay has passed through all stages of treatment and fractionation (ARG), (ii) Al-PILCFe, the clay would not pass the step of removal of free Fe (ARGFe) and (iii) Al-PILCFe/silt, clay has not gone through the steps of removing silt and free Fe (ARGFE/silt). XRD analysis showed that the Al-PILCs showed a basal spacing greater than the starting clays. The textural analysis indicated that the Al-PILCs and ARGs are mesoporous materials, with pore narrow slit type and slit type, respectively. Moreover, the Al-PILCs showed reasonable surface area greater than the corresponding ARGs. Other analyzes were made on clays: the content of Si, Fe and Al; CEC, FTIR, TGA and TGD. Brasgel pillared clays have been used as catalyst in the isomerization reaction of the styrene oxide in refluxing. The reaction was selective for the formation of phenylacetaldehyde. Al-PILCFe and Al-PILCFe/silt clays showed better catalytic performance (100% conversion in 20 min of reaction). Thus, the pillared clays Brasgel presented as a Clean Technology in the isomerization reaction of styrene oxide to phenylacetaldehyde. Keywords: Sustainable Development. Clean Technology. Green Chemistry. Pillared Clays. Isomerization of Epoxides.

Une bibliothèque de nouveaux catalyseurs bifonctionnels combinant à la fois l’aminocatalyse et l’activation acide par un acide phosphonique sur une même structure peptidique a été développée. Des variations structurales ont été apportées afin d’optimiser la géométrie du site catalytique. Le potentiel de ces catalyseurs a été testé sur la réaction d’addition de Michael stéréosélective d’aldéhydes sur divers nitroalcènes aromatiques. Dans des conditions optimisées, de très bonnes sélectivités (r.d. < 95:5 / r.e. < 93:7) ont été atteintes. Grâce à leur forte solubilité dans l’eau, ces catalyseurs ont été facilement extraits et réutilisés sur 10 cycles sans perte significative de sélectivité. Enfin, des études mécanistiques ont été menées afin de connaitre le mode d’action exact de ces catalyseurs. Tant l’énamine que l’activation acide se sont avérées essentielles pour que la réaction ait lieu. L’enchainement peptidique permet une réaction intramoléculaire et stéréosélective. / A novel bifunctional organocatalyst library combining both aminocatalysis and phosphonic acid activation on a peptide structure was developed. Some structural variations allowed the optimization of the catalytic site. The potential of these catalysts was evaluated on the stereoselective Michael addition of aldehydes with several aromatic nitroalkenes. In optimized conditions, very good selectivities (up to 95:5 d.r. and 93:7 e.r) were achieved. Due to their high water-solubility, the catalysts were easily recyclable and reused over several cycles without any significant loss of selectivities. Mechanistic investigations were carried out to understand the exact mode of action of the catalysts. Both enamine formation and acid activation were essential for the reaction to occur. The peptide structure allows an intramolecular and stereoselective reaction.

L'objectif de cette thèse est d'étudier la valorisation de la liqueur noire non soufrée par deux procédés hydrothermaux : la gazéification en eau supercritique et la liquéfaction hydrothermale. Ceux-ci seront comparés au procédé actuel de valorisation (évaporation puis combustion dans chaudière Tomlinson) selon 3 critères : le rendement énergétique, la récupération du sodium et la production de molécules aromatiques biosourcées.Lors de la gazéification, il a été montré que la formation de gaz est compétitive à celle de char. Une chauffe rapide et des températures élevées vont favoriser le rendement gaz et donc le rendement énergétique. Cependant les rendements énergétiques sont plus faibles que le procédé actuel car la conversion des composés aromatiques provenant de la lignine est faible dans la gamme de température étudiée. Lors d'un procédé en continu, à plus haute température (700°C) avec une chauffe rapide, le rendement énergétique peut être le double au procédé actuel (simulé à l'équilibre thermodynamique). La préhydrolyse du bois et l'utilisation de bois de résineux vont défavoriser la conversion de la liqueur noire en gaz.La liquéfaction quant-à-elle permet la formation composés phénoliques et d'un biocrude dont la combustion permettant de meilleur rendements énergétique que le procédé actuel. En effet, la lignine de la liqueur noire est hydrolysée en fragments réactifs, pouvant être soit dégradés soit se recombiner pour former le biocrude. Cette dernière est favorisée par la présence des carbohydrates. L'utilisation de bois de feuillus et la préhydrolyse vont améliorer le rendement énergétique.La récupération du sodium est satisfaisante pour les deux procédés, validant la faisabilité de la substitution de la chaudière par ces procédés hydrothermaux. / This thesis aims to study sulfur free black liquor valorization through two hydrothermal processes: supercritical water gasification and hydrothermal liquefaction. These processes will be compared to the industrial process (evaporation and Tomlinson boiler) with 3 mains criteria: energetic yield, sodium recovery and phenolic molecules production.In supercritical conditions, gas formation is competitive with char formation. Fast heating and high temperature permit to increase gas yield, thus energetic yield. However, conversion of phenolic compounds from lignin is low below 500°C, leading to a lower energetic yield than reference. In a continuous process, at high temperatures (700°C) and fast heating, energetic yield should be 2 times higher than industrial process (simulation at thermodynamic equilibrium). Wood prehydrolysis and softwood lead to a lower conversion of black liquor.Hydrothermal liquefaction produces a biocrude which can be burnt and phenolic platform compounds. Indeed, lignin is depolymerized into reactive fragments which can be degraded into platform phenolic molecules. Moreover, the recombination of these fragments, leading to biocrude formation, is favored by the carbohydrates derivatives in black liquor. Wood prehydrolysis and hardwood lead to better energetic and phenolic molecules yields.Sodium recovery is satisfactory for both processes. Substitution of Tomlinson recovery by a hydrothermal process is then possible.