Orientadores: Antonio José de Almeida Meirelles, Mariana Conceição da Costa, Jérôme Pauly / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-24T15:58:48Z (GMT). No. of bitstreams: 1 Carareto_NataliaDanieleDorighello_D.pdf: 2781126 bytes, checksum: a569200223f2c962deb5f7e6129613dd (MD5) Previous issue date: 2014 / Resumo: O estudo das propriedades físico-químicas de materiais graxos é uma demanda mundial crescente, principalmente devido ao incentivo do seu uso como fonte de energia e para a alimentação. Faz-se importante estudar e compreender todas as condições de equilíbrio que podem ser observadas durante o processamento de compostos graxos, por exemplo, óleos vegetais e biodieseis, desde a sua extração, refino e estocagem. Dados de equilíbrio sólido-líquido podem ser usados para melhorar ou propor novos processos de separação. Já o ponto de fulgor é uma propriedade importante que deve ser observada no armazenamento, transporte e produção de compostos inflamáveis, como o biodiesel. Este trabalho teve como objetivos estudar o equilíbrio sólido-líquido de misturas binárias graxas formadas por álcoois graxos, ésteres graxos ou ácidos graxos, e avaliar o ponto de fulgor de misturas de ésteres etílicos, que são constituintes principais de biodieseis, e etanol, presente em teores residuais. Os pontos de fulgor de ésteres etílicos, e também de misturas binárias destes ésteres com etanol foram determinados experimentalmente e a partir dos resultados foi proposto um modelo empírico para a predição do ponto de fulgor de biodieseis em função da sua composição e teor de etanol. Os diagramas de equilíbrio sólido-líquido de sistemas binários formados por ácidos + álcoois graxos ou formados por álcoois + álcoois graxos foram determinados experimentalmente através de calorimetria exploratória diferencial (DSC) com a intenção de melhor compreender as reações eutética, peritética e metatética que aparecem nos diagramas de equilíbrio tanto com taxas de aquecimento linear ou via o uso da ferramenta de stepscan DSC. Para complementar o estudo foram usadas técnicas de difração de Raios-X e microscopia óptica com controle de temperatura. O efeito da pressão sobre o equilíbrio sólido-líquido foi avaliado para misturas binárias de ésteres etílicos ou de álcoois graxos utilizando-se microscopia ótica acoplada a um aparato experimental que permite o aumento da pressão até 80 MPa. Foram utilizados os modelos termodinâmicos para coeficiente de atividade Margules 2 e 3-sufixos e NRTL para descrever a linha liquidus dos sistemas que apresentaram ponto peritético, e um modelo termodinâmico preditivo foi aplicado para modelar o ESL em função da pressão e, em ambos os casos, obteve-se um ajuste satisfatório em comparação aos dados experimentais / Abstract: The study on the physicochemical properties of fatty materials has acquired a growing importance, mainly due to the incentive of their use in energy and nutrition. The efficient production and use of fatty compounds requires a good knowledge of their properties and phase behavior that are necessary for development of processes, especially in production steps such as extraction and refining, but also during storage of the final products. Solid-liquid equilibrium data can be used to improve or propose new separation processes. Also the flash point is an important property that must be considered during storage, transportation and production of flammable compounds, such as biodiesel. This work aimed to study the solid-liquid equilibrium of binary mixtures consisting of fatty alcohols, fatty esters or fatty acids, and to evaluate the flash point of mixtures of ethyl esters, the major constituents of biodiesels, and ethanol, also present in biodiesel in residual levels. Flash points of ethyl esters, and also of the binary mixtures of ethyl esters with ethanol were determined experimentally. An empirical model for predicting the flash point of biodiesels as a function of composition and ethanol content was proposed. The solid-liquid phase diagrams of binary mixtures of fatty alcohol + fatty alcohol or fatty alcohols + fatty acid were determined experimentally by differential scanning calorimetry (DSC), using a linear heating rate, or by a stepscan DSC method, with the aim of investigating the occurrence of the eutectic, peritectic and metatectic reactions. X-ray diffraction and optical microscopy with temperature control techniques were applied to complement the understanding of the phase diagrams. The effect of pressure on the solid-liquid equilibrium was investigated for the binary mixtures of ethyl esters or fatty alcohols using an optical microscope coupled to a high pressure cell which allows the pressure increase up to 80 MPa. Margules 2 and 3-suffix and NRTL thermodynamic models were used for describing the liquidus line of the systems that presented peritectic point, and a predictive thermodynamic model was used to model the ESL function of pressure, which in both cases, gave a satisfactory fit compared to the experimental data / Doutorado / Engenharia de Alimentos / Doutora em Engenharia de Alimentos

L’étude des propriétés physico-chimiques des matières grasses constitue une demande mondiale croissante liée à l’augmentation constante de leur utilisation comme source d'énergie et pour l'alimentation. Une bonne connaissance de leurs propriétés thermophysiques et de leur comportement de phases est nécessaire pour la production, l'utilisation efficace de ces matières grasses et le développement des processus d'extraction au niveau du raffinage et du stockage. Des données d'équilibre solide-liquide peuvent être utilisées pour améliorer les procédés existants, et également pour le développement des nouveaux procédés de séparation. Ainsi, le point d'éclair est une propriété importante qui doit être observée pendant le stockage, le transport et la production de composés inflammables, tels que le biodiesel. Ce travail vise à étudier l'équilibre solide-liquide de mélanges binaires constitués d'alcools gras, d’acides gras et d’esters éthyliques. Il porte aussi sur l'évaluation du point d’éclair de mélanges d'esters éthyliques, constituants majoritaires du biodiesel, et de l'éthanol, présent à des niveaux résiduels dans le biodiesel. Les points d’éclair des esters éthyliques mais également des mélanges binaires d'esters éthyliques et d’éthanol, ont été déterminés expérimentalement. Un modèle empirique de prédiction des points d’éclair des biodiesels en fonction de leur composition et de leur teneur en éthanol a été proposé. Les diagrammes de phases solide-liquide des mélanges binaires d'alcool gras + alcool gras ou d’alcools gras + acide gras ont été déterminés expérimentalement par analyse calorimétrique différentielle (DSC). Cette étude permet de caractériser les réactions eutectique, péritectique et métatectique, en utilisant une vitesse de chauffe linéaire ou une méthode de Stepscan DSC. Des mesures de diffraction rayons X et de microscopie optique de contrôle de la température ont été appliquées pour compléter la compréhension des diagrammes de phases. L'effet de la pression sur l'équilibre solide-liquide a aussi été mesuré pour les mélanges binaires d’esters éthyliques ou d'alcools gras en utilisant un microscope optique couplé à une cellule à haute pression qui permet d’augmenter la pression jusqu'à 80 MPa sur une large gamme de température. Les modèles thermodynamiques Margules 2 et 3-suffix et NRTL ont été utilisés pour décrire la ligne du liquidus des systèmes présentant un point péritectique, alors qu’un modèle thermodynamique prédictif a permis de modéliser l'ESL en fonction de la pression. Dans les deux cas, on a observé un ajustement satisfaisant par rapport aux données expérimentales. / The study on the physicochemical properties of fatty materials has acquired a growing importance, mainly due to the incentive of their use in energy and nutrition. The efficient production and use of fatty compounds requires a good knowledge of their properties and phase behavior that are necessary for development of processes, especially in production steps such as extraction and refining, but also during storage of the final products. Solid-liquid equilibrium data can be used to improve or propose new separation processes. Also the flash point is an important property that must be considered during storage, transportation and production of flammable compounds, such as biodiesel. This work aimed to study the solid-liquid equilibrium of binary mixtures consisting of fatty alcohols, fatty esters or fatty acids, and to evaluate the flash point of mixtures of ethyl esters, the major constituents of biodiesels, and ethanol, also present in biodiesel in residual levels. Flash points of ethyl esters, and also of the binary mixtures of ethyl esters with ethanol were determined experimentally. An empirical model for predicting the flash point of biodiesels as a function of composition and ethanol content was proposed. The solid-liquid phase diagrams of binary mixtures of fatty alcohol + fatty alcohol or fatty alcohols + fatty acid were determined experimentally by differential scanning calorimetry (DSC), using a linear heating rate, or by a stepscan DSC method, with the aim of investigating the occurrence of the eutectic, peritectic and metatectic reactions. X-ray diffraction and optical microscopy with temperature control techniques were applied to complement the understanding of the phase diagrams. The effect of pressure on the solid-liquid equilibrium was investigated for the binary mixtures of ethyl esters or fatty alcohols using an optical microscope coupled to a high pressure cell which allows the pressure increase up to 80 MPa. Margules 2 and 3-suffix and NRTL thermodynamic models were used for describing the liquidus line of the systems that presented peritectic point, and a predictive thermodynamic model was used to model the ESL function of pressure, which in both cases, gave a satisfactory fit compared to the experimental data.

The Master thesis describe basic electrochemical processes in lithium-ion batteries and characteristic organic polar solvents for these articles. It focuses primarily on the aprotic liquid electrolytes for lithium-ion batteries and the subsequent use of gas chromatography to analyze the collected gas sample from the test article. For this experiment is, in this Master thesis, designed and described experimental arrangement in the form of a glass cell, which allows collection from the space above the working electrode. Finally, the work evaluates the effect of electrode potential on the stability of electrolytes in strongly positive potentials.