L’objet de cette thèse est l’étude de l’existence d’une quantification pour les sous-algèbres de Lie coisotropes des bigèbres de Lie. Une sous-algèbre de Lie coisotrope d’une bigèbre de Lie est une sous-algèbre de Lie qui est aussi un coidéal. Le problème de quantifications d’une sous-algèbre de Lie coisotrope fut posé par V. Drinfeld, lors de son étude de la quantification des espaces de Poisson homogènes G/C. Ces deux problèmes sont liés par le principe de dualité établi par N. Ciccoli et F. Gavarini. Dans cette thèse, nous cherchons à résoudre ce problème de quantification dans différents cadres. Premièrement, nous montrons qu’une quantification existe dans le cadre des bigèbres de Lie simple. Nous trouvons une quantification aux sous-algèbres de Lie coisotropes construites par M. Zambon. Puis nous établissons un lien entre ces quantifications et une classification des sous- algèbres coidéales à droite établie par I. Heckenberger et S. Kolb. Deuxièmement, nous trouvons une obstruction à la quantification universelle en utilisant une quantification d’ordre trois construite par V. Drinfeld. Nous montrons que cette obstruction disparait dans les exemples étudiés précédemment. Finalement, nous généralisons un résultat établi par P. Etingof et D. Kazhdan sur la quantification d’espaces de Poisson homogènes, liés aux sous-algèbres Lagrangiennes du double de Drinfeld. / The aim of this thesis is the study of quantization of coisotropic Lie subalgebras of Lie bialgebras.A coisotropic Lie subalgebra of a Lie bialgebra is a Lie subalgebra which is also a Lie coideal. The problem of quantization of coisotropic Lie subalgebra was set forth by V. Drinfeld, in his study of quantization of Poisson homogeneous spaces G/C. These problems are closely related to the duality principle established by N. Ciccoli and F. Gavarini.In this thesis, we search for an answer to this quantization problem in different settings. Firstly, we show that a quantization exists for simple Lie bialgebras by constructing a quantization of examples provided by M. Zambon. We then establish a link between the quantization which we constructed and a classification of subalgebras right coideals established by I. Heckenberger and S. Kolb. Secondly, we find an obstruction to the quantization in the universal setting by using a third-order quantization constructed by V. Drinfeld. We show that this obstruction vanishes in the examples studied earlier. Finally, we generalize a result of P. Etingof and D. Kazhdan on the quantization of poisson homogeneous spaces, linked to Lagrangian Lie subalgebras of Drinfeld's double.

L'hydrogène est envisagé comme vecteur énergétique pour le futur. En effet, son utilisation par oxydation dans les piles à combustible ne produit que de la vapeur d'eau et permet la production d'électricité et de chaleur. L'oxydation partielle des hydrocarbures, réaction exothermique, peut être une alternative ou un complément au vaporeformage (endothermique) pour la génération d'hydrogène. L'intérêt du propane, par rapport au méthane, est qu'il se liquéfie à une pression relativement faible. L'objectif de ce travail est l'étude cinétique de l'oxydation partielle catalytique du propane. C'est une réaction complexe : son mécanisme comporte des réactions catalytiques de surface couplées à des réactions en phase gazeuse par l'intermédiaire de radicaux. La réaction a été étudiée dans un réacteur auto-agité catalytique. Dans un premier temps une étude expérimentale a été réalisée sans catalyseur. Un mécanisme homogène a pu ainsi être validé. Ensuite, cette même réaction a été étudiée en présence de pastilles d'oxyde de cérium. Un mécanisme hétérogène a été écrit en utilisant le formalisme d'Eley-Rideal et celui de Langmuir-Hinshelwood. Les données cinétiques ont été estimées selon une méthode originale basée sur la théorie de Benson. En comparant les résultats expérimentaux et ceux issus de la simulation (effectués avec Chemkin®/Chemkin Surface®), un mécanisme hétéro-homogène a été validé sur un large domaine de conditions opératoires / Hydrogen is proposed as an energy vector for the future. Indeed, its energetic use by oxidation in fuel cells produces water vapor only. The partial oxidation of hydrocarbons, an exothermic reaction, can be an alternative or a complement to the steam cracking (endothermic) for hydrogen generation. Propane can be an interesting hydrocarbon for hydrogen production since it can be easily stored in liquid phase and distributed. The aim of this work is the kinetic study of the catalytic partial oxidation of propane. The reaction is complex: catalytic reactions are coupled to reactions in gas phase by the intermediary of radicals. The reaction was studied in a catalytic jet stirred reactor. At first, an experimental study was carried out without a catalyst. A homogeneous mechanism could be validated. Afterwards, this same reaction has been studied in presence of cerium oxide pellets. A heterogeneous mechanism was written using the formalism of Eley-Rideal and that of Langmuir-Hinshelwood. The kinetics parameters are estimated by methods derivated from Benson's techniques. Comparing experimental results and those from the simulation (carried out by Chemkin®/Chemkin Surface®), a hetero-homogeneous mechanism was validated in our experimental conditions

Education and training affect the way children's behavior, we shape children's attitudes and values. One of the ways which we can develop the personality of a child in kindergarten is to use the principle of individuation. The theoretical part is, besides development of individualization in the upbringing and education of children of preschool age, given the current requirements for the individualization of children in kindergartens. It discusses the development and acceptance of the basic needs of children of preschool age, specifies the conditions, the position of teacher for individualizing education of children in kindergarten. The practical part verifies the possibility of individualization in age heterogeneous and homogeneous model. Assesses differences and experience in these models in the approaches of preschool teachers including the effect of a specific environment specific kindergarten.

The carbonylation of methanol to acetic acid is one of the most important applications in homogeneous catalysis. The first chapter comprises a review on the mechanistic studies into the catalytic cycle of the ‘Monsanto process’ and includes some of the most prominent studies into the use of phosphines in the rhodium-catalysed carbonylation of methanol. The second chapter of this thesis reports on an investigation into the application of rhodium complexes containing several C4 bridged diphosphines, namely BINAP, dppb, dppx and dcpb as catalysts for hydrogen tolerant methanol carbonylation. An investigation into the structure, reactivity and stability of pre-catalysts and catalyst resting states of these complexes has also been carried out. The origin of this hydrogen tolerance is explained based on the differing reactivities of the Rh acetyls with hydrogen gas, and by considering the structure of the complexes. In the third chapter I report on an investigation into how electronic properties and coordination mode affect the elimination of phosphonium salts from rhodium complexes. The stability of a range of monodentate, bidentate and tridentate rhodium-phosphine complexes was tested. I also report on the formation of a novel bidentate complex containing a partially quaternised TRIPHOS ligand and investigate the mechanism of formation using 13CH3I. Strong evidence is also presented supporting a dissociative mechanism as the means of phosphine loss from the rhodium centre. In the final chapters I report an investigation into the stability of rhodium-aminophosphine ligand complexes and into increasing the solubility of potential rhodium pre-catalysts through the use of amine-containing phosphine ligands.

Depuis le début des années 1990, l'hétéroannélation de Larock est apparue comme une méthode de choix pour obtenir, en une seule étape, des indoles 2,3-disubstitués. Cependant, bien qu'efficace, certains inconvénients restaient associés à cette stratégie comme l'utilisation d'un système catalytique homogène associé à l'emploi de sels. Pour cette raison, nous avons développé une nouvelle méthodologie sans sels ou additifs par catalyse hétérogène. Différents catalyseurs commerciaux ou faciles d'accès (Pd/C ou [Pd]/NaY) ainsi que de nouveaux complexes au palladium immobilisés sur SBA-15 ont été testés. De façon surprenante, ces nouvelles conditions ont permis une activation de 2-bromoanilines et ce, sans l'emploi d'additifs. Une autre méthode d'obtention de ces hétérocycles a émergé ces dernières années et se pose comme une alternative aux couplages traditionnels : l'arylation d'indoles. Malgré de nombreuses améliorations, aucun travail ne décrivait une procédure permettant une arylation complémentaire C2 ou C3 d'indoles libres avec un système catalytique unique. Nous avons développé un tel système, basé sur une pallado-catalyse dans l'eau. Cette stratégie permet d'atteindre des sélectivités C2/C3 ou C3/C2 élevées avec de bons rendements isolés par un simple contrôle du couple (base/halogénure d’aryle).Enfin, dans le cadre de nos travaux visant la synthèse par catalyse hétérogène de produits à haute valeur ajoutée, nous avons initié des études sur l'obtention de pyrroloiminoquinones. La méthode consistant en une catalyse hétérogène monotope en seulement deux grandes étapes devrait permettre un accès rapide à de nombreux dérivés bioactifs isolés d'organismes marins. / Since the beginning of the 90's, the Larock heteroannulation became a method of choice to afford, in a single step, 2,3-disubstituted indoles. While effective, this methodology suffered of drawbacks lied to the use of salts, additives and homogeneous catalyst. Thus, we developed the first ligand and salt free heterogeneous Larock heteroannulation. Different commercially available, home made catalysts (Pd/C or [Pd]/NaY) or new palladium complexes immobilised onto mesoporous silica SBA-15 were evaluated. Surprisingly, this methodology allowed an activation of the 2-bromoanilines without using additives. Another procedure to obtain indole nucleus emerged over the past few years as an outstanding alternative to traditional cross-coupling reactions: namely the “direct arylation”. Despite major improvements, no report focuses on complementary C2 and C3-arylation procedures by means of a unique catalytic system. Herein, we describe an innovative “on water” palladium-catalyzed C–H arylation of (NH)-indoles that is site-selective through a base/halide-controlled using cheap reagents. This methodology allows the preparation of either C2- or C3-arylindoles with high isolated yields. Finally, as part of our project related to syntheses of high added value products by heterogeneous catalysis, we investigated studies in order to obtain pyrroloiminoquinones. This new methodology using only two steps will permit an access to numerous bioactive analogues.

La synthèse de nitriles gras à partir de ressources renouvelables est un domaine qui attire depuis quelques temps les industries de la parfumerie, des polymères et des biocarburants pour avion. Ce travail de thèse s’est plus particulièrement intéressé à réduire de 100°C la température de travail pour les procédés en phase liquide et gaz, au moyen de catalyseurs plus efficaces. Le procédé en phase liquide a été étudié en terme de catalyse homogène et les formes actives à base de zinc ou indium ont été plus particulièrement détaillées ; des conditions ont été établies pour obtenir une réduction de 50°C de la température de travail. Le procédé en phase gaz a été étudié en terme de catalyse hétérogène, les catalyseurs obtenus ou synthétisés étant caractérisés par microcalorimétrie d’adsorption ; des corrélations entre la conversion de l’ester et l’acidité du lit catalytique ont été trouvées à 300°C, et des conditions expérimentales ont été développées pour obtenir une conversion totale à une température réduite de 100°C sur des catalyseurs choisis / The production of fatty nitriles from renewable sources has lately become attractive for the perfume, polymer and aviation biofuel industry. The present work investigated both liquidand gas-phase processes in the aim of developing catalysts working at 200°C, this is 100°C lower than the state-of-the-art. Homogeneous catalysis was described with zinc and indium based species for the liquid-phase process, succeeding in reducing by 50°C the operating temperature. Heterogeneous catalysts with acid-base features were characterized by adsorption calorimetry and tested in the gas-phase process, leading to correlations between acidity and ester conversion at 300°C, while conditions were found on selected catalysts in order for the process to perform the complete conversion of esters into nitriles at 200°C

Dans cette thèse, on s'intéresse au groupe de Brauer non ramifié des espaces homogènes à stabilisateur non connexe et à ses applications arithmétiques. On développe notamment différentes formules de nature algébrique et/ou arithmétique permettant de calculer explicitement, tant sur un corps fini que sur un corps de caractéristique 0, la partie algébrique du groupe de Brauer non ramifié d'un espace homogène G\G' sous un groupe linéaire G' semi-simple simplement connexe à stabilisateur fini G, le tout en donnant des exemples de calculs que l'on peut faire avec ces formules. Pour ce faire, on démontre au préalable (à l'aide d'un théorème de Gabber sur les altérations) un résultat décrivant la partie de torsion première à p du groupe de Brauer non ramifié d'une variété V lisse et géométriquement intègre sur un corps fini ou sur un corps global de caractéristique p au moyen de l'évaluation des éléments de Br(V) sur ses points locaux. Les formules pour un stabilisateur fini sont ensuite généralisées au cas d'un stabilisateur G quelconque via une réduction de la cohomologie galoisienne du groupe G à celle d'un certain sous-quotient fini. Enfin, pour K un corps global et G un K-groupe fini résoluble, on démontre sous certaines hypothèses sur une extension déployant G que l'espace homogène V:=G\G' avec G' un K-groupe semi-simple simplement connexe vérifie l'approximation faible (ces hypothèses assurant la nullité du groupe de Brauer non ramifié algébrique). On utilise une version plus précise de ce résultat pour démontrer ensuite le principe de Hasse pour des espaces homogènes X sous un K-groupe G' semi-simple simplement connexe à stabilisateur géométrique fini et résoluble, sous certaines hypothèses sur le K-lien défini par X. / This thesis studies the unramified Brauer group of homogeneous spaces with non connected stabilizer and its arithmetic applcations. In particular, we develop different formulas of algebraic and/or arithmetic nature allowing an explicit calculation, both over a finite field and over a field of characteristic 0, of the algebraic part of the unramified Brauer group of a homogeneous space G\G' under a semisimple simply connected linear group G' with finite stabilizer G. We also give examples of the calculations that can be done with these formulas. For achieving this goal, we prove beforehand (using a theorem of Gabber on alterations) a result describing the prime-to-p torsion part of the unramified Brauer group of a smooth and geometrically integral variety V over a global field of characteristic p or over a finite field by evaluating the elements of Br(V) at its local points. The formulas for finite stabilizers are later generalised to the case where the stabilizer G is any linear algebraic group using a reduction of the Galois cohomology of the group G to that of a certain finite subquotient.Finally, for a global field K and a finite solvable K-group G, we show under certain hypotheses concerning the extension splitting G that the homogeneous space V:=G\G' with G' a semi-simple simply connected K-group has the weak approximation property (the hypotheses ensuring the triviality of the unramified algebraic Brauer group). We use then a more precise version of this result to prove the Hasse principle forhomogeneous spaces X under a semi-simple simply connected K-group G' with finite solvable geometric stabilizer, under certain hypotheses concerning the K-kernel (or K-lien) defined by X.

Cette thèse s'inscrit dans le prolongement du résultat d'Apéry donnant l'irrationalité de ζ (3) et de celui de Ball-Rivoal prouvant qu'il existe une infinité d'entiers impairs en lesquels la fonction zêta de Riemann prend des valeurs irrationnelles. Un outil crucial dans la démonstration de Ball-Rivoal est le critère d'indépendance linéaire de Nesterenko, qui a été généralisé par Fischler et Zudilin pour exploiter sous des hypothèses très restrictives la présence de diviseurs communs aux coefficients des formes linéaires. Une généralisation ultérieure due à Fischler s'applique lorsqu'on dispose d'approximations simultanées des nombres réels en question (et non plus de combinaisons Z-linéaires petites de ces nombres).Dans cette thèse, on améliore ce dernier résultat en affaiblissant considérablement les hypothèses sur les diviseurs. On démontre aussi un critère d'indépendance linéaire analogue, dans l'esprit de celui de Siegel. Dans une autre partie en commun avec Zudilin, on construit, en utilisant des identités hypergéométriques, des approximations simultanées de ζ (2) et ζ (3) qui permettent de démontrer en même temps l'irrationalité de ces deux nombres. En appliquant essentiellement le critère démontré précédemment, on en déduit une minoration des combinaisons Z-linéaires de 1, ζ 2) et ζ (3), sous des hypothèses de divisibilité très fortes sur les coefficients (si bien que l'indépendance linéaire sur Q de ces trois nombres est toujours conjecturale). / This Ph.D. thesis lies in the path opened by Apéry who proved the irrationality of ζ(3) andalready followed by Ball-Rivoal who proved that there are infinitely many odd integers at which Riemann zeta function takes irrational values. A fundamental tool in the proof of Ball-Rivoal is Nesterenko’s linear independence criterion. This criterion has been generalized by Fischler and Zudilin to use common divisors of the coefficients of linear forms, under some restrictive assumptions. Then Fischler gave another generalization for simultaneous approximations (instead of small Z-linear combinations).In this Ph.D. thesis, we improve this last result by greatly weakening the assumption on thedivisors. We prove also an analogous linear independence criterion in the spirit of Siegel. Inanother part joint with Zudilin, we construct simultaneous linear approximations to ζ(2) and ζ(3) using hypergeometric identitites. These linear approximations allow one to prove at thesame time the irrationality of ζ(2) and that of ζ(3). Then, using a criterion from the previouspart, we deduce a lower bound on Z-linear combinations of 1, ζ(2) and ζ(3), under somestrong divisibility hypotheses on the coefficients (so that the Q-linear independence of thesethree numbers still remains an open problem).

Le couplage diphasique-turbulence est une propriété clé des écoulements cavitants, qui est un frein important à l’amélioration des modèles de cavitation et de turbulence. Réaliser des simulations directes (DNS) est le moyen proposé ici pour s’affranchir du modèle de turbulence et obtenir des informations nouvelles sur les phénomènes mis en jeu. Ce type de simulation est exigeant sur le plan numérique, et requiert le développement d’un solveur spécifique intégrant les spécificités des modèles de cavitation. Cela inclue notamment des schémas de discrétisation d’ordre élevé, un solveur direct, et une résolution multi-domaines associée à une parrallélisation efficace. Une discrétisation par différences compactes finies s’avère être le meilleur choix. La contrainte de rapidité et de parrallélisation impose un algorithme où les systèmes résoudre n’impliquent des multiplications des variables implicites que par des coefficients invariants au cours du calcul. Un nouvel algorithme réunissant ces critères a été développé durant cette thèse, à partir de la combinaison de la méthode de Concus & Golub et d’une méthode de projection, qui permet de résoudre les équations associées à la modélisation homogène de la cavitation. Une nouvelle approche de vérification de ce nouvel algorithme est également proposée et mise en œuvre sur la base de la méthode des solutions manufacturées (MMS). / Cavitation-turbulence interactions are problematic aspect of cavitating flows which imposes limitations in development of better cavitation and turbulence models. DNS simulations with homogeneous mixture approach are proposed to overcome this and offer more insight into the phenomena. As DNS simulations are highly demanding and a variety of cavitation models exists, a tool devoted specifically to them is needed. Such tools usually demand application of highly accurate discretization schemes, direct solvers and multi domain methods enabling good scaling of the codes. As typical cavitating flow geometries impose limits on suitable discretization methods, compact finite differences offer the most appropriate discretization tool. The need for fast solvers and good code scalability leads to request for an algorithm, capable of stable and accurate cavitating flow simulations where solved systems feature multiplication of implicitly treated variables only by constant coefficients. A novel algorithm with such ability was developed in the scope of this work using Concus and Golub method introduced into projection methods, through which the governing equations for homogeneous mixture modeling of cavitating flows can be resolved. Work also proposes an effective and new approach for verification of the new and existing algorithms on the basis of Method of Manufactured Solutions.

A celulose é o biopolímero mais abundante da Terra. Ela contempla muitos dos requisitos desejados para substituição de polímeros sintéticos oriundos de petróleo. Entretanto, a insolubilidade da celulose em água e em solventes orgânicos comuns e a sua decomposição antes da fusão impedem seu processamento por extrusão. Uma solução para esse problema é a preparação de derivados de celulose que possam ser processados por extrusão ou regeneração em não solvente. Nesse ponto, os ésteres de celulose, utilizados há décadas, possuem destaque apresentando grande interesse comercial. Contudo, o contínuo estudo dos ésteres de celulose quanto aos métodos de preparação, de suas propriedades e o desenvolvimento de novos compostos se faz necessário para melhorar e ampliar suas aplicações. Sendo assim, essa tese de doutoramento contribuiu para a química dos ésteres de celulose das seguintes formas: (i) estudo de solventes para síntese de ésteres de celulose em condições reacionais homogêneas; e (ii) síntese, caracterização e moldagem de ésteres mistos de celulose com estrutura controlada. Dentro do primeiro tema, soluções binárias de dimetilsulfóxido (DMSO) e líquidos iônicos (ILs) a base de 1-metilimidazol (acetato de 1-(1-butil)-3-metilimidazólio, C4MeImAc; acetato de 1-(2-metóxietil)-3-metilimidazólio, C3OMeImAc) foram avaliadas como solvente para dissolução e acilação (síntese de acetato de celulose e benzoato de celulose) de celulose sob condições reacionais homogêneas. O foco dessa etapa de trabalho foi verificar se a presença de oxigênio etéreo na cadeia lateral do anel imidazólio favorecia a dissolução e acilação da celulose, uma vez que ele é mais básico que o correspondente grupo metilênico. Surpreendemente, o C4MeImAc apresentou melhor capacidade de dissolução de celulose e os ésteres de celulose nele preparados possuem maior grau de substituição. Para compreensão dessa aparente contradição foram utilizadas as técnicas de reologia; de espectroscopia de 1H e 13C NMR de soluções de celobiose em IL/DMSO; e de solvatocromismo (avaliação da acidez e basicidade de Lewis). Todos essesresultados indicam uma menor interação entre a celulose e o IL contendo cadeia alcóxi e corroboram os dados recém-publicados de cálculos teóricos, que indicam a ciclização, via formação de ligações de hidrogênio intramolecular, do cátion C3OMeIm+. Na tentativa de impedir a ciclização do cátion imidazólio e consequentemente melhorar as propriedades do IL contendo cadeia alcóxi, ILs metilados nas posições 1 e 2 do anel imidazólio foram testados. Apesar de a metilação melhorar a capacidade dos ILs para dissolução e acilação da celulose, não foi observado o efeito esperado para a presença do oxigênio etéreo na cadeia lateral do IL. No segundo tema de estudo, ésteres mistos de celulose (CellCarboxy/Ts) contendo grupo tosilato (com grau de substituição fixo, DSTs ≈ 1,0) e grupos carboxilatos (com grau de substituição variável, DSAcyl) com diferentes hidrofobicidades (acetato, butanoato, hexanoato) foram sintetizados em meio homogêneo de cloreto de lítio/N,N-dimetilacetamida (LiCl/DMAc). A dependência no DSAcyl das propriedades de superfície (polaridade empírica, acidez e basicidade de Lewis; ângulo de contato e energia de superfície) desses ésteres de celulose foi determinada e apresentam correlações simples. Os Cell-Carboxy/Ts também foram caracterizados quanto às suas propriedades térmicas verificando-se que o aquecimento dos ésteres leva à saída dos grupos acila antes do grupo tosilato e que a temperatura de decomposição desses ésteres é menor que a de fusão. Portanto, os Cell-Carboxy/Ts só podem ser moldados por regeneração a partir de soluções. Sendo assim, as técnicas de gotejamento de solução de éster de celulose (solvente acetona) em não solvente (água) e de eletrofiação de solução de Cell-Carboxy/Ts (solvente acetona/DMAc) foram otimizadas para preparação de microesferas e microfibras, respectivamente. As estruturas obtidas apresentaram diâmetro médio de 240 ± 35 nm e 230 ± 20 nm, respectivamente. A aplicabilidade da espectroscopia no infravermelho e no UV-VIS foi avaliada para determinação do DSAcyl dos ésteres mistos obtendo-se resultados satisfatórios. Esses métodos são interessantes, pois permitem a economia de amostra (ca. de 1 % da massa necessária no método tradicional de titulação), o que é relevante em estudos exploratórios de ésteres de celulose onde poucos gramas de amostra são preparados. / Cellulose is most abundant biopolymer in the Earth. It complies with many desired requirements for substitution of petroleum-based polymers. However, cellulose is insoluble in water and common organic solvents and decomposes before undergoes melt flow, which prevents its extrusion processing. One possible solution for this problem is the preparation of cellulose derivatives that can be process by extrusion or by regeneration into non-solvents. In this point, cellulose esters, used for decades, stand out showing great commercial interest. In spite of their long use, the continuous research on cellulose ester focused on new synthetic methods, determination of properties and development of new compounds is necessary to improve and expand their commercial application. Therefore, this PhD thesis contributes to the cellulose esters chemistry in the following way: (i) study of solvents for synthesis of cellulose esters in homogenous reaction conditions (HRC); and (ii) synthesis, characterization and shaping of cellulose mixed esters with controlled structure. In the first approach, binary mixtures of dimethyl sulfoxide (DMSO) and ionic liquids (ILs) based on 1-methylimidazole (1-(1-butyl)-3-methylimidazolium acetate, C4MeImAc; 1-(2-methoxyethyl)-3-methylimidazolium acetate, C3OMeImAc) were evaluated as solvent for cellulose dissolution and acylation (synthesis of cellulose acetate and cellulose benzoate) under HRC. This part of project aim was verify if the presence of ether oxygen on side chain of imidazolium ring can favored the cellulose dissolution and acylation, once it is more basic than the corresponding methylene group. Surprisingly, the C4MeImAc shows higher ability to dissolves cellulose and the biopolymer esters prepared in it have higher degree of substitution. In order to understand this apparent contradiction, were employed the following techniques: rheology, 1H and 13C NMR spectroscopy of celobiose solution in IL/DMSO; and solvatochromism (evaluation of Lewis acidity and basicity). All results indicate a lower interaction between cellulose and the IL with alkoxy side chain and corroborate the recently published data of theoretical calculation which proposed the cyclization of C3OMeIm+ cation, via intramolecular hydrogen bond. In attempt to avoid the imidazolium cation cyclization and consequently improve the properties ofIL containing alkoxy side chain, ILs methylated at positions 1 and 2 of imidazolium cation were tested. Despite methylation improve the IL ability on cellulose dissolution and acylation, the expected effect for the presence of ether oxygen on IL side chain was not observed. In the second part of this study, cellulose mixed esters (CellCarboxy/Ts) containing tosylate unit (fixed degree of substitution, DSTs ≈ 1.0) and carboxylate groups (variable degree of substitution, DSAcyl) with different hydrophobicity (acetate, butanoate, hexanoate) were synthesized in homogeneous medium of lithium chloride/N,N-dimethylacetamide (LiCl/DMAc). The dependence on DSAcyl of surface properties (empical polarity, Lewis acidity and basicity, contact angle, surface energy) of Cell-Carboxy/Ts was determined and show simple correlation. The thermal properties of Cell-Carboxy/Ts were also evaluated verifying that the heating of these cellulose esters promotes the scisson of acetate group before the tosylate ones. Further Cell-Carboxy/Ts decompose before they undergo melt-flow, so these cellulose esters can be shaped only by regeneration from their solution. In this way, Cell-Carboxy/Ts was shaped into microspheres and microfibers using the techniques of dropping (acetone solution into water) and electrospinning (acetone/DMAc solution), respectively. The structures obtained have average diameter of 240 ± 35 nm e 230 ± 20 nm, respectively. The applicability of infrared and UV-VIS spectroscopies to determine the DSAcyl of cellulose mixed esters was evaluated obtaining satisfactory results. These methods are interesting because they use few amount of sample (about 1 % of weight required by traditional titration method). The sample economy is relevant in exploratory studies of cellulose esters since they are carried out on few grams of sample.