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Glycerol and fructose are molecules that are readily available in substantial quantities fromthe biomass. In this work dehydration routes for valorization of these compounds wereinvestigated. Therefore, zirconia and titania based catalysts, and calcium phosphate materialswere prepared and evaluated in the glycerol dehydration in gas phase. Niobia-ceria mixedoxides and mesoporous Nb2O5-MeO2 (M = Ce, Zr, Ti) mixed oxides were prepared andtested in fructose dehydration reaction in aqueous phase. The surface acid-base properties ofthe studied catalysts were correlated to their catalytic performance.

Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2016-09-26T14:37:02Z No. of bitstreams: 2 dissertação final recorrigida-capa.pdf: 401652 bytes, checksum: 86330537bc26151925bb8c03de4f993a (MD5) Dissertação Versão Final.pdf: 2578250 bytes, checksum: 19ad7de8c52c85cf3e787b04c08ce9ef (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2016-09-26T15:02:14Z (GMT) No. of bitstreams: 2 dissertação final recorrigida-capa.pdf: 401652 bytes, checksum: 86330537bc26151925bb8c03de4f993a (MD5) Dissertação Versão Final.pdf: 2578250 bytes, checksum: 19ad7de8c52c85cf3e787b04c08ce9ef (MD5) / Made available in DSpace on 2016-09-26T15:02:14Z (GMT). No. of bitstreams: 2 dissertação final recorrigida-capa.pdf: 401652 bytes, checksum: 86330537bc26151925bb8c03de4f993a (MD5) Dissertação Versão Final.pdf: 2578250 bytes, checksum: 19ad7de8c52c85cf3e787b04c08ce9ef (MD5) / CAPES / O presente trabalho relata o estudo químico das sementes de Spondias tuberosa Arr. Cam., como aproveitamento de resíduos industrial. Spondias tuberosa, pertencente a família Anacardiaceae, é uma árvore endêmica do semi-árido brasileiro, cujos frutos conhecidos como umbu, são comercializados in natura ou em forma de polpa e suas raízes e folhas também podem ser utilizadas como alimento. O extrato metanólico bruto das sementes do umbu foi submetido à partição líquido- líquido e sua atividade citotóxica e antioxidante foi avaliada. O extrato hexânico obtido das sementes apresentou-se atóxico para o teste de letalidade de Artemia salina e os demais extratos foram moderadamente tóxicos. Em relação à atividade antioxidante, a fase AcOEt demonstrou ser a mais ativa, seguido da CHCl3. A partir de sucessivos fracionamentos cromatográfico da fase clorofórmica da sementes de Spondias tuberosa permitiu o isolamento de uma mistura de ácidos graxos que posteriormente foram submetidos à transesterificação obtendo-se onze ésteres metílicos, além de uma mistura de sitosterol e estigmasterol. Do fracionamento da fase acetato de etila foi isolado o 5-hidroximetil-2-furfural (5-HMF). Do extrato hexânico foi isolado uma mistura de triglicerídeos que foi submetido à reação de saponificação seguida de esterificação obtendo-se assim, uma composição química com nove ésteres metílicos. A elucidação estrutural das substâncias isoladas foi baseada na análise de dados de espectros de Massas, dos espectros de RMN de 1H e 13C, juntamente com a RMN de correlação (HMQC e HMBC) e comparação com dados da literatura. / This paper reports the chemical study of seeds of Spondias tuberosa Arr. Cam., As utilization of industrial waste. Spondias tuberosa, belonging to Anacardiaceae family, is an endemic tree from the Brazilian semi-arid region, known as umbu whose fruits are sold fresh or in the form of pulp and the leaves and roots can also be used as food. The crude extract from the seeds of umbu methanol was subjected to liquid- liquid partition and their cytotoxic and antioxidant activity was evaluated. The hexane extract obtained from the seeds showed up were nontoxic to moderately toxic lethality test of Artemia salina and other extracts. In relation to the antioxidant activity, the EtOAc phase was shown to be the most active, followed by CHCl3. From successive chromatographic fractionation of the chloroform phase seeds Spondias tuberosa allowed isolation of a mixture of fatty acids which were subsequently subjected to transesterification to give methyl esters eleven, and a mixture of sitosterol and stigmasterol. The fractionation of the ethyl acetate phase was isolated 5-hydroxymethyl-2-furfural (5-HMF). The hexane extract was isolated a mixture of triglycerides which was subjected to saponification reaction followed by esterification thereby obtaining a chemical composition with nine methyl ester. The structural elucidation of the isolated compounds was based on the analysis of spectral data Masses, the NMR spectra of 1H and 13C NMR along with the correlation (HMQC and HMBC) and comparison with literature data.

L'épuisement progressif des matières premières d'origine fossile et la nécessité de réduire les émissions de gaz à effets de serre ont conduit la communauté scientifique à rechercher de nouveaux matériaux dont la production ne dépendra pas de ressources non renouvelables. Dans un autre temps ces matériaux pourront déjà être introduits sur le marché afin de substituer des produits déjà existant qui proviennent de matières premières fossiles. Par exemple, l'acide 2,5-furandicarboxylique (FDCA) obtenu par valorisation de la biomasse lignocellulosique est un potentiel substituant de l'acide téréphtalique actuellement utilisé pour la production de polyesters. En effet, le FDCA peut être obtenu par oxydation sélective du 5-hydroxyméthylfurfural (HMF) synthétisé à partir de la biomasse lignocellulosique. Ainsi, ce travail de thèse peut être défini par deux problématiques principales : (1) Le développement de catalyseurs pour l'oxydation de HMF en FDCA sans utiliser de bases inorganiques et (2) Développement de membranes catalytiques de polymères pour la future adaptation du procédé d'oxydation en réacteur à flux continu. Pour ce qui concerne l'oxydation de HMF dans des conditions neutres, une première étude s'est intéressée à la possibilité d'utiliser de l'oxyde de nickel nanométrique comme support pour des nanoparticules. Ensuite, la possibilité d'utiliser des nanoparticules de Pt supportées sur du TiO2 obtenues par décomposition contrôlée de clusters carbonyliques a été étudiée. Ainsi, des membranes de polymère obtenues par électrospinning, contenant les nanoparticules métalliques étudiées précédemment, ont été appliquées comme système catalytique pour l'oxydation du HMF / The depletion of fossil-derived resources and the need to decrease the emission of green-house gases led scientists to look for sustainable materials to replace the already existing fossil-derived ones. For instance, 2,5-furandicarboxylic acid (FDCA) has been pointed out as the bioderived counterpart of terephthalic acid for the synthesis of polyesters. In fact, FDCA could be obtained by means of selective oxidation of 5-hydroxymethylfurfural (HMF), a bio-derived platform molecule produced by glucose hydrolysis. This reaction is known to be catalyzed by supported metal nanoparticle systems in presence of inorganic bases under batch conditions. This work deals with the development of catalytic systems able to perform the base-free HMF oxidation, since the possibility to circumvent base addition leads more sustainable processes. In particular, two different sets of catalytic systems have been studied: mono- and bimetallic Au and Pd nanoparticles on nano-sized NiO, and mono- and bimetallic Pt/Sn systems on titania, prepared via cluster precursor decomposition. Another topic that will be discussed in this thesis focuses on the development of catalytically active polymeric membranes obtained via electrospinning and their application as catalytic system for HMF oxidation either under basic and neutral aqueous conditions. In details, polyacrylonitrile and nylon have been tested as electrospun polymeric matrixes for the embedding of Au-based nanoparticles and Pt clusters

Increasing energy demand and various problems associated with fossil fuels such as environmental pollution, global warming and diminishing petroleum reserves have greatly stimulated production of fuels and chemicals from renewable sources. Lignocellulosic biomass has been considered as one of the potential sources for a variety of fuels and industrial chemicals. 5-Hydroxymethylfurfural (HMF) has been identified as an excellent platform molecule because it is a flexible intermediate for the synthesis of bio-renewable fuels and materials. HMF can be easily obtained from acid-catalyzed hydration of biomass-derived carbohydrates (hexoses) in various media. HMF can be converted to energy products such as 2,5-bis(alkoxymethyl)furans (BAMFs), monomers for high-value polymers such as 2,5-bis(hydroxymethyl)furan (BHMF), and valuable intermediates for fine chemicals. Recently, magnetic nanoparticle based catalysts attracted more attention due to their good stability and easy separation from the reaction mixture by a permanent magnet. This unique magnetic separation property makes MNPs more effective than conventional filtration or centrifugation as it prevents loss of the catalyst. This dissertation work focuses on, firstly, studying the effectiveness of silica coated magnetite (Fe3O4) nanoparticles MNPs supported with sulfonic acid groups (Fe3O4@SiO2-SO3H) on the dehydration of glucose to HMF. Secondly, preparing a cost-effective catalytic transfer hydrogenation system for the selective transformation of HMF into BHMF via Meerwein-Ponndorf-Verley (MPV) reaction over the copper iron magnetic catalyst supported on activated carbon in ethanol solvent with the absence of molecular hydrogen. Thirdly, producing alkoxymethylfurans (AMFs) which are considered a potential biofuels by using two-step sequential reactions with cheap heterogeneous zinc-iron oxides magnetic nanocatalyst for the hydrogenation of HMF to furfuryl alcohols in various alcohols solvents in the absence of molecular hydrogen followed by solid Brønsted acid catalyst for the etherification reaction of furfuryl alcohol derivatives. All prepared heterogeneous catalysts were characterized by FTIR, XRD, H2-TPR, XPS, ICP-OES, HRTEM-EDX, and N2 adsorption-desorption isothermal analyses (BET and BJH) and were tested for recyclability. The chemical products were identified by high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and products quantities were calculated by using calibration curves of chemical standards. Various reaction conditions such as reaction temperature, reaction time, catalyst amount, and alcohol type were optimized.

The Maillard reaction products (MRPs) 3-deoxyglucosone (3-DG) and 5-hydroxymethylfurfural (HMF), which are formed during the thermal processing and storage of food, come into contact with technologically used yeasts during the fermentation of beer and wine. In order for the yeast cells to work efficiently, handling of the stress-inducing carbonyl compounds is essential. In the present study, the utilization of 3-DG and HMF by 13 Saccharomyces yeast strains (7 brewer’s yeast strains, 1 wine yeast strain, 6 yeast strains isolated from natural habitats) was investigated. All yeast strains studied were able to metabolize 3-DG and HMF. 3-DG is mainly reduced to 3-deoxyfructose (3-DF) and HMF is completely converted to 2,5-bishydroxymethylfuran (BHMF) and 5-formyl-2-furancarboxylic acid (FFCA). The ratio of conversion of HMF to BHMF and FFCA was found to be yeast strain-specific and no differences in the HMF stress tolerance of the yeast strains and species were observed. After incubation with 3-DG, varying amounts of intra- and extracellular 3-DF were found, pointing to a faster transport of 3-DG into the cells in the case of brewer’s yeast strains. Furthermore, the brewer’s yeast strains showed a significantly higher 3-DG stress resistance than the investigated yeast strains isolated from natural habitats. Thus, it can be shown for the first time that Saccharomyces yeast strains differ in their interaction of 3-DG induced carbonyl stress.

L'objectif de la thèse est d'étudier la transformation de la fraction cellulosique de la biomasse en acide lévulinique. Cet acide est une molécule plateforme permettant un accès à de multiples produits, tels que des solvants, des monomères ou encore des molécules à plus forte valeur ajoutée.Nous proposons d'étudier la transformation de la cellulose en acide lévulinique catalysée par des solutions aqueuses concentrées en acides de Brønsted. La forte acidité de ces milieux et leur capacité à rompre les liaisons hydrogène de la cellulose rendent possible des réactions à température modérée (80°C), ce qui laisse espérer la production sélective d'acide lévulinique.L'état de l'art concernant la production d'acide lévulinique à partir de glucose ou de cellulose est d’abord présenté, ainsi qu’une étude bibliographique sur les techniques permettant la mesure d’acidité de milieux concentrés.La caractérisation de l’acidité des milieux semblant être un point clé pour contrôler la réaction, la seconde partie concernera les mesures d’acidité des milieux concentrés utilisés. La méthodologie expérimentale pour identifier et quantifier les produits de réaction de la cellulose ainsi que les paramètres critiques qui la régissent sont ensuite détaillés.Enfin l’étude s’achèvera par deux chapitres traitant de la transformation du glucose ou la cellulose en acide lévulinique dans des milieux comportant une forte acidité de Brønsted combinée, ou non, avec des sels métalliques. La transformation du glucose conduit à des sélectivités en acide lévulinique de 50 mol% dans l’acide sulfurique 65 % et supérieures à 70 mol% dans l'acide sulfurique 48 % en présence de chlorure d'aluminium hydraté. La transformation de la cellulose conduit à des sélectivités en acide lévulinique d'environ 43 mol% dans les milieux acides de Brønsted concentrés et 60 mol% lorsque des sels métalliques sont ajoutés. De telles sélectivités en acide lévulinique n'ont jamais été décrites dans les milieux concentrés. / The thesis presented in this document aims at converting lignocellulosic biomass into levulinic acid. This target is a valuable building block which can lead to various products.This platform intermediate can be obtained by acid-catalyzed conversion of cellulose contained in raw biomass. However, the state of the art concerning this acid-catalyzed reaction revealed that the current conditions (diluted acids in harsh temperature conditions) result in numerous by-products formation. The selectivity issue often deals with process control, in particular with reaction time optimization.Our approach lies in using concentrated Brønsted acids as alternative media to catalyze cellulose conversion. Indeed, the high acidity level allow the interaction with hydrogen bonds in cellulose fibrils and favor cellulose decristallization. This property should promote the transformation of cellulose into levulinic acid at lower temperature thus limiting the formation of by-products. Therefore, acidity measurements in such media have been developed and performed. An extensive study on glucose and Avicel cellulose conversion in concentrated aqueous solutions of sulfuric acid was performed at 80°C. Levulinic acid yields, up to 50 mol%, were determined by HPLC analysis and a special attention was dedicated to the identification and quantification of soluble or insoluble by-products, allowing the characterization of new species never described in aqueous solutions. Referring to the acidity levels previously determined, a comparison between acidity and catalytic results will be setted.Finally, the effect of metallic chloride addition on the transformation of glucose and cellulose in sulphuric acid solutions has been investigated, revealing improvements yielding up to 70 mol% levulinic acid. This range of selectivity is unprecedented at such a low temperature.