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Desenvolvimento de novas combinações monômero - catalisador para a produção de polímeros via ROMP / Development of new catalyst-monomer pairs for bio-renewable thermoset production by ROMPMarcela Portes de Castro 19 July 2016 (has links)
Polímeros com diferentes características foram sintetizados a partir da polimerização por abertura de anel (Ring Opening Metahesis Polymerization-ROMP) de três diferentes monômeros de norborneno (NBE) derivados com triglicerídeos ou monoglicerídeos oriundos de óleos de mamona e de soja: Norbornenyl-functionalized castor oil (NCO), Norbornenyl-functionalized castor oil alcohol (NCA) e o novo Norbornenyl-functionalized epoxized soybean oil (NESBO). Utilizou-se como precursores catalíticos complexos do tipo [RuCl2(PPh3)2(amina)], amina = peridroazepina e piperidina, e catalisadores de Grubbs (1a e 2a geração). Foram investigados os efeitos da estrutura do monômero e do catalisador no processo de polimerização, bem como as propriedades térmicas e mecânicas dos polímeros resultantes. Através da ressonância magnética nuclear de hidrogênio (NMR-1H) foi determinado o número de sítios ativos (unidades de norborneno) por cadeia de ácido graxo em cada monômero: 1,8 em NCO, 2,6 em NCA e 4.5 em NESBO. O número de unidades monoméricas, assim como a viscosidade de cada monômero, desempenha um papel importante no controle da iniciação e propagação do processo de polimerização e nas propriedades finais dos polímeros obtidos. Os complexos do tipo Ru-amina, produziram materiais poliméricos similares aos obtidos com o catalisador de 1° Grubbs. Foram realizados estudos para otimizar as condições experimentais nas reações de ROMP, através da análise das estabilidades térmicas dos polímeros obtidos constatou-se a influência das variáveis tipo de catalisador, concentração de catalisador, tempo de reação, número de NBE por estrutura do monômero e a influência da adição de ácido na atividade catalítica dos complexos. Os valores de transição vítreas foram determinados através de DSC, o monômero de partida mostrou uma influência mais significativa sobre o valor de Tg dos polímeros obtidos do que o tipo de catalisador utilizado. Os estudos mecânicos dos materiais resultantes indicaram que foram obtidos desde materiais borrachosos a rígidos alterando a natureza do monômero e o tipo de catalisador utilizado e não foi possível estabelecer uma correlação entre as densidades de reticulação e a quantidade de anéis NBE da estrutura, nas condições analisadas. A cinética do processo de cura foi acompanhada através da ROMP induzida por temperatura, sob diferentes condições de frequência angular, temperatura e tempo. / Polymers with different characteristics were synthesized from the ring opening polymerization (ROMP) of three different monomers of norbornene (NBE) derived with triglycerides or monoglycerides from castor and soybean oils: Norbornene-functionalized castor oil (NCO), Norbornene-functionalized alcohol castor oil (NCA) and the new Norbornene-functionalized epoxidized soybean oil (NESBO). It was used, as catalyst precursors, complexes of the type [RuCl2(PPh3)2(amine)], amine = perhydroazepine and piperidine and the catalyst Grubbs (1st and 2nd generation). The effects of the structure of the monomer and catalyst in the polymerization process, as well as the thermal and mechanical properties of the resulting polymers, were investigated. Through the nuclear magnetic resonance of proton (1H-NMR), it was determined the number of active sites (norbornene units) per chain of fatty acid in each monomer: 1.8 to NCO, 2.6 to NCA and 4.5 to NESBO. The number of monomeric units (active sites for ROMP), as well as the viscosity of each monomer plays an important role in controlling the initiation and propagation of polymerization and the final properties of the polymers obtained. The Ru-amine complex type, produced polymeric materials similar to those obtained with Grubbs catalyst 1st. Studies were performed to optimize the experimental conditions in ROMP reactions, through analysis of the thermal stabilities of the obtained polymers was found to influence the variables: type of catalyst, catalyst concentration, reaction time, number of NBE in structure of the monomer and influence of acid addition on the catalytic activity of the complex. The glass transition values were determined by DSC, the starting monomer showed a more significant influence over the Tg value of all the obtained polymers compared to the all used catalysts. The mechanical studies of the resulting materials indicated that rubbery and rigid materials were obtained, by changing the nature of the monomer and type of catalyst, although it was not possible to determine a correlation between the crosslinking densities and the quantity of NBE rings of the structure for the analyzed conditions. The kinetic for the cure process was followed through the induced ROMP by temperature under different conditions of angular frequencies, temperature, and time.
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The effect of bioactive constituents on plant oil stability /Abuzaytoun, Reem, January 2005 (has links)
Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Restricted until October 2006. Bibliography: leaves 108-134.
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Soybean oil based copolymers containing silicon, boron or phosphorus: polymerization, characterization and fire retardance propertiesSacristán Benito, Marta 24 February 2010 (has links)
Introducción y antecedentes El concepto de desarrollo sostenible surgió como idea principal tras la reunión de la comisión Brundtland en 1987. Esta reunión fue organizada por Naciones Unidas con el fin de tratar el deterioro del medio ambiente, originado por el desarrollo descontrolado de la humanidad. El desarrollo sostenible fue definido como un avance social y económico que asegure una vida sana y productiva al ser humano, pero que no comprometa las posibilidades de desarrollo de las generaciones venideras. Entre las conclusiones alcanzadas, se resaltó la necesitad de disponer de una mayor variedad de fuentes de energía. La filosofía de esta cumbre fue recogida en Agenda 21, un documento que pretendía servir como guía general de actuación para alcanzar un desarrollo sostenible a todos los niveles. Respecto a las ciencias, Agenda 21 subrayaba la necesidad de emplear todo el conocimiento científico en la consecución de los objetivos del desarrollo sostenible. En este sentido, la Environmental Protection Agency acuñó en 1998 un término, Green Chemistry, que reunía estas ideas y las aplicaba a la química a través de 12 principios que debían ser cumplidos en el camino hacia una química sostenible. Entre estos principios, el uso de fuentes renovables para la obtención de materias primas ha adquirido gran relevancia debido a las previsiones de agotamiento de una de las fuentes de energía y materias primas más importantes: el petróleo. Los aceites vegetales se incluyen entre estas fuentes renovables de materias primas, siendo actualmente una de las fuentes renovables más utilizadas por la industria química. Los aceites vegetales están básicamente compuestos por triglicéridos, que son moléculas formadas por glicerol y tres ácidos grasos. En general los ácidos grasos pueden ser completamente saturados o contener varios dobles enlaces que en algunos casos pueden encontrarse conjugados, pero también existen ácidos grasos que contienen grupos hidroxilo o epóxido. Cada aceite vegetal posee una distribución característica de ácidos grasos que determina sus propiedades físicas y químicas. En lo que respecta a la química de los polímeros, los aceites vegetales constituyen una atractiva materia prima debido a la amplia gama de transformaciones químicas que pueden llevarse a cabo para sintetizar monómeros de diversa naturaleza. La epoxidación de los dobles enlaces internos es la transformación más común, ya que permite, a través de la apertura del anillo oxiránico con diferentes reactivos, la introducción de una gran variedad de grupos funcionales. Los dobles enlaces internos pueden polimerizarse directamente en condiciones térmicas, con iniciadores de radicales o por polimerización catiónica. / Introducction The sustainable development concept came out of the United Nations Commision on Environment and Development in 1987 (Bruntland Commission) and it is defined as "the development that meets the needs of the present without compromising the ability of future generations to meet their own needs". From this point, both the society and the industry have considered what a sustainable development really means and the best ways to start to achieve it from their own standpoints. The principles of the United Nations Conference on environment and Development (UNCED) held in June 1992 in Rio de Janeiro, and Agenda 21, were formulated with the aim of preparing the world for the challenges of the 21st century. In this context, during the early 1990s the US Environmental Protection Agency (EPA) coined the phrase Green Chemistry "To promote innovative chemical technologies that reduce or eliminate the use of generation of hazardous substances in the design, manufacture and use of chemical products". The main challenges of Green Chemistry and Engineeiring can be summarized as: · utilizing renewable instead of scarce resources. · avoiding toxic/dangerous chemicals in safer processes to obtain safer products. · minimizing energy use. · minimizing waste and resource use, re-using products, recovering and recycling materials. So making processes globally more efficient. Plant oils are one of the most widely applied renewable raw materials in the chemical industry for non-fuel applications. Vegetable oils are triglycerides (tri-esters of glycerol with long-chain fatty acids) with varying composition of fatty acids depending on the plant they are extracted from. Depending on the composition of plant oils, their Chemicals and physical properties are different.Vegetable oils are very used in polymer chemistry. Triglycerides have different reactive points through which we can obtain polymers from plant oils.There are two main approaches:The first one is the chemical modification of the triglycerides obtaining a large number of polymerizable monomers like expoxides or alcohols. The second approach is the direct polymerization of the carbon-carbon doubles bonds of plant oils through a free radical or a cationic mechanism.The free radical polymerization of double bonds has received less attention than cationic mechanism which has been very studied by Larock's group.In both cases thermosetting polymers with comparable properties to those of industrial can be obtained. Because of increasing use of synthetic polymeric materials during the lasts decades and the large fraction of the fire load in homes, it is necessary the use of fire retardants to reduce combustibility of the polymers, and smoke or toxic fume production. To get these requirements, the development of effective flame retardant materials is a key factor. To reduce the flammability, flame retardants can act in the gas phase or in condensed phase. In the gas phase fire retardants act as scavengers of the highly reactive radical species that propagate the combustion. In the condensed-phase fire retardants interfere in the thermal degradation processes modifying the reaction pathways and promoting the formation of char instead of volatile degradation products. Finally some flame retardants can act in both phases. Objectives The main objective of this Thesis was to develop new fire retardant biobased thermosets from vegetable oils as renewable resources. To achieve this goal it was carried out the cationic copolymerization of soybean oil, styrene and divinylbenzene with different silicon-or boron-or phosphorus containing comonomers.
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Assessment of omega-3 long chain polyunsaturated fatty acid incorporation in broiler chicken meat following the consumption of omega-3 rich vegetable oils.Kartikasari, Lilik Retna January 2009 (has links)
Dietary omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs), eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), have beneficial health effects and hence increasing the consumption of these fatty acids is recommended by health authorities. The most common dietary source of EPA, DPA and DHA is seafood, but few Australians habitually consume fish and on average eat less than one meal of fish per week. Thus if Australians are to meet the dietary guidelines for n-3 fatty acid intake, there is a need to develop a source of n-3 rich foods that fit into a typical Australian diet. Feeding fish oils rich in n-3 LCPUFA to chickens has proven problematic due to alteration in organoleptic properties. The incorporation of vegetable oils rich in n-3 PUFA, alpha-linolenic acid (ALA, 18:3n-3) into the diet of chickens is potentially an alternative way to provide meat rich in n-3 LCPUFAs as ALA is the precursor of EPA and DHA. However, most vegetable oils also contain the n-6 (n-6) PUFA, linoleic acid (LA, 18:2n-6) which competes with ALA for the same enzymes in their metabolism to LCPUFA. This thesis addressed two crucial issues relating to the conversion of ALA into EPA, DPA and DHA of chicken tissues. The objectives of the first experiment were to examine the effects of increasing the ALA content of diets on the conversion of ALA into EPA, DPA and DHA by measuring their accumulation in chicken meat (breast and thigh) and to determine if there was an optimum level of ALA (at a fixed level of LA) in this process. The ratio of LA to ALA of the diets ranged from 10.5:1 to 0.6:1. The findings in this study demonstrated that there was no optimum level of dietary ALA and as indicated by the observation that EPA, DPA and DHA continued to increase in breast and thigh as the ratio of LA to ALA decreased in the diet. In general, DPA achieved higher levels than DHA. The experimental diets with the lowest LA to ALA ratio elevated the incorporation of EPA and DHA into breast and thigh meat to levels 5 and 4-fold, respectively relative to birds fed the highest LA to ALA ratio. In contrast, arachidonic acid (AA, 20:4n-6) in all groups reduced with decreasing LA to ALA ratio in the diets. The results indicated that the dietary treatments did not significantly change the growth performance of chickens. The objective of the second experiment was to assess the regulatory effect of dietary LA on the conversion of ALA into EPA, DPA and DHA. While in the first experiment the diets varied in the level of ALA but had a constant LA level, in this experiment the level of ALA in the diets was held constant and the level of LA was varied. The LA to ALA ratio of experimental diets ranged from 1.4:1 to 2.1:1. The results of this study indicated that the highest LA to ALA ratio (2.1:1) resulted in the lowest n-3 LCPUFAs, EPA, DPA and DHA in meat samples. For example, the total n-3 LCPUFA levels in the breast meat of birds fed with the lowest LA to ALA ratio was 16% higher than the n-3 LCPUFA in the breast of birds fed the highest LA to ALA ratio. This study indicated that the strongest influence on EPA, DPA and DHA accumulation in chicken tissues was the level of ALA in the diet. The experimental diets did not appear to affect the growth performance of chickens. In conclusion, increasing the ALA content of chicken diets may result in a meat source high in n-3 LCPUFAs that may reduce pressure on diminishing marine stocks as well as offering health benefits to Australians. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1369065 / Thesis (M.Ag.Sc.) - University of Adelaide, School of Agriculture, Food and Wine, 2009
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Aspects of essential oil secretion in vascular plants /Gersbach, Paul V. January 2001 (has links)
Thesis (Ph.D.) -- University of Western Sydney, 2001. / "This thesis is presented in fulfilment of the degree of Doctor of Philosophy in Science at the University of Western Sydney, Richmond, New South Wales, Australia" Bibliography : p. 145-163.
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Processo de descasque de crambe (Crambe abyssinica Hochst) visando a extração de óleo e armazenamento /Santos, Silas da Silva, 1972. January 2016 (has links)
Orientador: Marco Antônio Martin Biaggioni / Banca: Osmar Delmanto Junior / Banca: Ivan Fernandes de Souza / Resumo: A prensagem mecânica é o método mais empregado para extração do óleo de diversos tipos de oleaginosas, constituindo-se em uma operação simples que não exige mão de obra qualificada e é facilmente adaptável a diversos tipos de grãos. Entretanto, as prensas contínuas de pequena capacidade, com grande potencial de utilização nas pequenas comunidades rurais, apresentam baixa eficiência de extração, deixando uma quantidade significativa de óleo na torta de crambe. A operação de retirada das cascas dos frutos de crambe, antes da prensagem, constitui-se em um fator importante que pode otimizar a extração mecânica do óleo de crambe, reduzindo o teor de óleo que se perde pela casca. Por outro lado, a possibilidade de danificação mecânica durante a compressão e atrito, comprometendo o potencial de armazenamento dos grãos, deve ser considerada. O objetivo deste trabalho foi avaliar o rendimento de óleo extraído mecanicamente do crambe, contendo diferentes percentagens de casca, bem como, o possível efeito imediato e latente do processo de descasque dos grãos submetidos a diferentes sistemas de armazenagem. Este trabalho foi desenvolvido em duas fases. Na primeira fase, foram realizados os testes de rendimento de extração do óleo pelo método mecânico de prensagem a frio, a partir do crambe submetido aos seguintes tratamentos de descasque: grãos com casca (testemunha), grãos sem casca, grãos com 10% de casca e grãos com 20% de casca. Para avaliar o efeito do descasque foi utilizado um de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The mechanical pressing (expelling) is the most commonly used method for extracting oil from various types of oilseeds, constituting of a simple operation that requires no skilled labor and is easily adaptable to various types of grain. However, small expellers, with great potential for use in small rural communities, have low extraction efficiency, leaving a significant amount of oil in the crambe presscake. The operation of the crambe fruit hulling before the pressing is an important factor that can optimize the mechanical extraction of the crambe oil, reducing the oil contained that is lost by the hull. On the other hand, the possibility of mechanical damage during compression and friction, compromising the grain storage potential, should be considered. The objective of this work was to evaluate the yield of mechanically extracted oil from the crambe, containing different percentages of hull, as well as the possible immediate and latent effect of the hulling process of the grains submitted to different storage systems. This work was developed in two phases. In the first phase, the oil extraction yield tests were performed by the cold pressing method, having the crambe submitted to the following hulling treatments: whole grains (control), totally dehulled (Hulless), partially dehulled with 10% hull, and partially dehulled with 20% hull. To evaluate the dehulling effect, a completely randomized experimental design was used, with four treatments and four replications. The res... (Complete abstract click electronic access below) / Mestre
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Caracterização de óleos extraídos de sementes de frutas : composição de ácidos graxos, tocoferóis e carotenóides /Malacrida, Cassia Roberta. January 2009 (has links)
Orientador: Neuza Jorge / Banca: Crispin Humberto Garcia Cruz / Banca: Magali Conceição Monteiro da Silva / Banca: Odair Zenebon / Banca: Roseli Aparecida Ferrari / Resumo: No Brasil, muitas frutas comestíveis são processadas para fabricação de sucos, doces, geléias, polpas e extratos, gerando uma grande quantidade de resíduos tais como sementes, cascas e bagaços. Este estudo teve como objetivo caracterizar e verificar um melhor aproveitamento dessas sementes, possibilitando agregar valor econômico a estes subprodutos. Para tanto, os objetivos principais deste trabalho foram: caracterizar sementes de frutas comumente cultivadas no Brasil (laranja, limão, tangerina, melão, melancia, mamão, maracujá e goiaba) quanto à composição centesimal, determinar as características físico-químicas, composição em ácidos graxos, tocoferóis, carotenóides, teores de compostos fenólicos totais e matéria insaponificável nos óleos extraídos dessas sementes, e avaliar a estabilidade oxidativa e a atividade antioxidante dos mesmos. As sementes foram separadas das frutas, lavadas, secas à temperatura ambiente, trituradas e o óleo extraído em extrator Soxhlet. Todas as sementes apresentaram teores relativamente elevados de lipídios (14,01-41,66%) e os óleos revelaram um elevado grau de insaturação (67,55- 88,14%), destacando-se como ácidos graxos principais o oléico e o linoléico. Com relação às propriedades físico-químicas, os óleos apresentaram características semelhantes a óleos convencionais e as porcentagens de matéria insaponificável foram de 0,70-1,51%. As concentrações de tocoferóis totais variaram de 74,71 mg.Kg-1, para o óleo de semente de mamão, a 748,11 mg.Kg-1, para o óleo de semente de melancia, sendo o d-tocoferol quantificado em todos os óleos. Os principais carotenóides quantificados nos óleos analisados foram luteína, b-criptoxantina e b-caroteno. O óleo de sementes de mamão apresentou a maior concentração de carotenóides totais (7,05 mg.Kg-1), enquanto no óleo de maracujá nenhum carotenóide foi ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In Brazil, many edible fruits are processed to produce juice, candy, jam, concentrate and puree, originating a vast quantity of waste such as seeds, peels and pulps. The aim of the present study was to investigate the possible utilization of fruit seeds, allowing to add economic value to these subproducts. Thus, the main objectives of this work were: to characterize seeds of commonly cultivated species of fruits in Brazil (orange, lemon, tangerine, melon, watermelon, papaya, passion fruit and guava) as for their proximal composition; to determine the physico-chemical characteristics, fatty acid composition, tocopherols, carotenoids, total phenolic compounds and unsaponifiable matter in the oils extracted of these fruit seeds; and to evaluate the oxidative stability and the antioxidant activity of the seed oils. The seeds were removed from the fruits, washed, dried at room temperature, ground and the oils extracted using a Soxhlet extractor. All seeds showed considerable lipid contents (14.01-41.66%) and the oils revealed high unsaturated fatty acids percentage (67.55-88.14%) with oleic and linoleic fatty acids being prominent. Regarding to physico-chemical properties, the seed oils compared favorably to conventional vegetable oils and the unsaponifiable matter percentages were 0.70-1.51%. The total tocopherol concentrations ranged between 74.71 mg.Kg-1 for papaya seed oil to 748.11 mg.Kg-1 for watermelon seed oil, being the d-tocopherol quantified in all oils. The major carotenoids quantified in the analyzed oils were lutein, b-criptoxantin and b-carotene. The papaya seed oil showed the highest total carotenoid concentration (7.05 mg.Kg-1) while no carotenoid was quantified in the passion fruit seed oil. Total phenolic contents obtained in the analyzed oils (922.92-1,428.97 mg gallic acid equivalents per kilogram of oil) were higher than those cited in the literature to soybean... (Complete abstract click electronic access below) / Doutor
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Optimization of biodiesel production using heterogenous catalyst in a packed bed reactorAyodeji, Olagunju Olusegun January 2018 (has links)
Submitted in fulfillment of the requirements for the degree of Master of Engineering: Chemical Engineering, Durban University of Technology, Durban, South Africa, 2018. / Industrial development is associated with an increase in pollution levels and rising fuel prices. Research on clean energy contributes to reduction of fossil fuel dependency, decrease in ozone layer depletion and reduction in emission of toxic gases. The development of renewable energies increases the energy independence and reduces the impact of environmental pollution from fossil fuels.
The biodiesel market is among the fastest growing renewable energy markets and its demand in the energy sector has tremendously increased over the last decade due to its environmental friendly qualities. Biodiesel is considered as a promising diesel fuel substitute based on the similarities of its properties with that of petroleum based diesel fuel. However, the high cost of the feedstock, environmental pollution as a result of wastewater generated from a homogeneous process has limited its full implementation. In addition, other technical challenges encountered during the production such as the immiscibility of the reagents and the reversibility of the transesterification reaction calls for innovative technologies to be developed. One promising solution to these issues is the use of membrane technology to serve as a reaction and separating medium for the production of biodiesel.
This study is aimed at optimizing biodiesel production from vegetable oils using heterogeneous catalysts in a ceramic membrane. The objectives were to evaluate the performance of calcium oxide (CaO) as a catalyst supported on activated carbon in a membrane reactor for biodiesel production. Further still, to evaluate the membrane performance regarding permeate quality and to optimize the process using design of experiment. The final objective was to investigate the influence of operating parameters such as temperature, methanol/oil ratio, catalyst amount and reaction time on biodiesel yield.
The transesterification of soya bean oil with methanol in the presence of a supported catalyst was carried out on a laboratory scale. The membrane reactor was designed and assembled for this purpose. The membrane reactor integrated many procedures such as
combining reaction and separation in a single unit, continuous mixing of raw materials and maintaining high mass transfer between the immiscible phases during the reaction. The effect of the process parameters on the biodiesel production and FAME (fatty acid methyl ester) yields were investigated.
One factor at a time (OFAT) experiments were conducted to identify the optimum range of the yield. The membrane reactor produced a permeate stream which separated at room temperature into a FAME rich non-polar phase and a methanol polar phase. The
optimum range was between 90% - 94% within a reaction time of 60 – 180 minutes, methanol to oil ratio 3:1 - 9:1 and temperature range of 60 0C - 70 0C. Methyl ester produced met the ASTM D6751 and SANS 1935 specifications.
The response surface methodology (RSM) based on the central composite design (CCD) was used to optimize the process. The optimization experiments were conducted around the optimum range established by the OFAT method. The optimum condition for transesterification of soya bean oil to fatty acid methyl ester was obtained at 3 g/L catalyst concentration, 65 0C temperature, 4.5:1 methanol to oil molar ratio and 90 minutes reaction time. At these optimum conditions, the FAME yield was 96.9 %, which is well within the yield of 97.7 % as predicted by the model.
In conclusion, this work presents a study of high quality biodiesel production using a ceramic membrane reactor with the advantage of selectively permeating FAME and methanol. This study therefore showed that the use of a membrane for biodiesel production conserved water for other purposes; eliminates the purification step and wastewater generation thereby reducing the cost of biodiesel production. / M
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Desenvolvimento de um sistema de liberação controlada de princípios ativos do oleo de Azadirachta indica A. Juss em matriz de poli(álcool vinílico) (PVA) para aplicações em veterinária / Development of a controlled delivery system of Azadirachta indica A. Juss active agents oil in poly(vinyl alcohol) (PVA) matrix for veterinary applicationsANDRADE, ANDREIA B.N. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:41:28Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:22Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Modificações catalíticas de óleos vegetais para a produção de insumos químicos / Catalytic modifications of vegetable oils for the production of chemical productsTeixeira, Sérgio 17 August 2018 (has links)
Orientador: Ulf Schuchardt / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-17T06:24:21Z (GMT). No. of bitstreams: 1
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Previous issue date: 2006 / Resumo: Derivados de óleos vegetais foram preparados utilizando-se catalisadores homogêneos e heterogêneos. Em quatro diferentes estudos foram produzidos epóxidos, hidroxi-éteres vicinais, antioxidantes e surfactantes. Os epóxidos graxos foram preparados a partir de oleato de metila, bem como óleo de soja e seus ésteres metílicos através de três métodos: (i) químio-enzimático; (ii) convencional (geração in situ de um perácido de cadeia curta) e (iii) catalítico, com peróxido de hidrogênio na presença de aluminas. Em todos os sistemas foram obtidas conversões > 90 % e seletividades > 95 %. Os rendimentos em epóxidos do sistema envolvendo as aluminas foram semelhantes aos obtidos com perácidos de cadeia curta. A alumina mais ativa foi utilizada em quatro epoxidações sem perdas significativas na atividade. Os experimentos de abertura de anéis oxirânicos presentes em ésteres graxos epoxidados, para a obtenção de hidroxi-éteres vicinais, foram realizados com metanol, isopropanol e etilenoglicol. Nos experimentos com isopropanol, o catalisador mais ativo - argila montmorilonita modificada com o ácido dodecatungstofosfórico - permitiu conversão > 98 % e seletividade de 95 % para os produtos de interesse. Nas reações com etilenoglicol foram obtidos produtos com elevadas massas molares, resultantes da formação de dímeros, trímeros e de outras espécies oligoméricas. Em outra parte do estudo foram sintetizados antioxidantes lipofílicos a partir de ácido ascórbico e compostos graxos, como estearato de vinila, oleato de metila e ácido oléico. Nas reações catalisadas por preparados enzimáticos, o substrato vinílico mostrou-se o mais eficiente, levando a rendimentos próximos de 75 % para o ascorbato nas condições otimizadas. O procedimento adotado mostrou-se inadequado para a obtenção de ascorbatos insaturados (rendimentos abaixo de 25 %). Na parte final, é descrita a preparação de uma betaína a partir de óleo de babaçu, com o objetivo de avaliar a utilização desse insumo em substituição aos óleos de coco e de palmiste, normalmente utilizados como matéria-prima na produção de betaínas. A metodologia empregada mostrou-se adequada e o produto foi obtido como uma solução aquosa com concentração próxima de 30 % (m/m). / Abstract: Vegetable oil derivatives were prepared using homogeneous and heterogeneous catalysts. In four different studies, epoxides, vicinal hydroxyl-ethers, antioxidants and surfactants were obtained. The fatty epoxides were prepared from methyl oleate, as well as soybean oil and its methyl esters mixture, using three methods: (i) chemo-enzymatic; (ii) conventional (short chain peracid in situ generation) and (iii) catalytic, with hydrogen peroxide in presence of aluminas. Conversion > 90 % and selectivity > 95 % were obtained for all the systems. For the system with alumina, epoxide yields were next to the obtained with short chain peracids. The most active alumina could be used in four epoxidations without significant reactivity loss. The ring opening reactions using epoxidized fatty esters were carried out with methanol, isopropanol and ethylene glycol. With isopropanol, the more active catalyst - K10 montmorillonite clay modified with dodecatungstophosphoric acid - allowed a conversion > 98 % and selectivity of 97 %. High molar mass products were obtained in the reactions with ethylene glycol; such products result from the formation of dimers and trimers, among other oligomeric species. In another part of the work, lipophilic antioxidants were synthesized from ascorbic acid and fatty compounds, such as vinyl stearate, methyl oleate and oleic acid, using enzymatic catalysts. The vinylic substrate was the more efficient, allowing 75 % of ascorbate yield. The employed procedures were unsuitable for the production of unsatured ascorbates (yields > 25 %). The final part describes the preparation of a betaine from babaçu oil. The aim was to evaluate this oil as a substitute for coconut and palmiste oils, usually used for betaine production. The methodology was suitable and the product was obtained as an aqueous solution (30 % m/m). / Doutorado / Quimica Inorganica / Doutor em Ciências
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