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Avaliação de óleos de cianobactérias como matéria-prima lipídica para síntese de biodiesel pela rota etílica; Evaluation of Cyanobacteria Oil as Lipid Feedstock for Biodiesel Synthesis by Ethanol Route

Rós, Patrícia Caroline Molgero da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/08/2012 PT
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O objetivo principal deste trabalho foi avaliar o óleo produzido por cianobactérias como matéria-prima lipídica para sintetisar biodiesel pela rota etílica empregando catalisadores heterogêneos. Cinco linhagens de cianobactérias não produtoras de toxinas: Microcystis aeruginosa NPCD-1, Synechococcus sp. PCC7942, Chlorogloea sp. CENA170, Leptolyngbya sp. CENA104 e Trichormus sp. CENA77 foram inicialmente cultivadas e avaliadas, tomando por base parâmetros como: produtividade de biomassa celular, teor de lipídeo e composição em ácidos graxos. Os valores mais elevados de produtividade celular e de lipídeo foram obtidos para as linhagens M. aeruginosa NPCD-1, Trichormus sp. CENA77 e Synechococcus sp. PCC7942. As matérias-primas lipídicas oriundas das linhagens selecionadas foram ainda caracterizadas quanto as propriedades reológicas (viscosidade), térmicas (termogravimetria) e químicas (espectroscopia na região de infravermelho). Na etapa seguinte, as condições de cultivo das linhagens foram estudadas e otimizadas por meio de um planejamento fatorial avaliando as variáveis intensidade luminosa (50 a 150 ?mol m-2s-1) e concentração de Na2CO3 (0,5 a 1,5 g/L), considerando como variáveis resposta a produtividade celular e o teor de lipídeo. A análise estatística indicou que a intensidade de luz influenciou positivamente os valores de produtividade celular para todas as linhagens estudadas...

Heterogeneous catalysis afford biodiesel of babassu, castor oil and blends

De Carvalho, Lee M.G.; De Abreu, Wiury C.; De O. E Silva, Maria Das Graças; De O. Lima, José Renato; De Oliveira, José Eduardo; De Matos, José Milton E.; De Moura, Carla V.R.; De Moura, Edmilson M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 550-557
ENG
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); This work describes the preparation of babassu, castor oil biodiesel and mixtures in various proportions of these oils, using alkaline compounds of strontium (SrCO3 + SrO + Sr (OH)2) as heterogeneous catalysts. The mixture of oils of these oleaginous sources was used in the production of biodiesel with quality parameters that meet current legislation. The catalyst was characterized by X-ray diffractometry (XDR), physisorption of gas (BET method), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The viscometric technique was used to monitor the optimization. The transesterification reactions performed using strontium compounds reached conversion rates of 97.2% babassu biodiesel (BB), 96.4% castor oil biodiesel (COB) and 95.3% Babassu/Castor Oil Biodiesel 4:1 (BBCO41). Printed in Brazil - ©2013 Sociedade Brasileira de Química.

Produção de biodiesel etílico via catálise heterogênea; Production of ethyl biodiesel via heterogeneous catalysis

Gabriela Bevilaqua
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 02/03/2011 PT
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O impacto ambiental devido ao uso de combustíveis fósseis e as questões políticas envolvendo seu uso tem impulsionado a busca por combustíveis derivados da biomassa. Desta forma, o biodiesel tem aparecido nesse contexto de modo a substituir, parcialmente ou totalmente, a utilização de combustíveis derivados de petróleo. O biodiesel é definido como uma mistura de ésteres obtidos principalmente a partir da reação de triacilglicerídios e álcool. A reação mais comumente utilizada para sua síntese é a transesterificação. Algumas condições reacionais afetam o rendimento, tais como: proporção entre triacilglicerídios e álcool (razão molar), concentração de catalisador (por massa de óleo), temperatura, tempo e tipo de catalisador. Embora os catalisadores homogêneos sejam usados com maior freqüência na indústria, eles apresentam o inconveniente de produzir sabão e desativar durante o processo. Além disso, não podem ser recuperados. Neste cenário, passou-se a investigar o uso dos catalisadores heterogêneos na produção de biodiesel. O presente trabalho teve como objetivo estudar a síntese de biodiesel etílico utilizando catalisador zeolítico faujasita impregnado com hidróxido de potássio e óxido de cálcio como catalisadores heterogêneos...

Sucrose Inversion An Experiment on Heterogeneous Catalysis

Adélio Mendes; Fernão D. Magalhães; Luis M. Madeira
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
ENG
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llustration of heterogeneous catalysis concepts in laboratory courses is not usually simple or economical. For our undergraduate senior lab course we have developed an environmentally friendly experiment dealing with several aspects of heterogeneous catalysis, having in mind the use of readily available and relatively inexpensive equipment, and chemicals on a compact setup, which students can safely operate. The experiment deals with the acid-catalyzed sucrose inversion, performed in packed bed chemical reactors, where the catalyst is a cation-exchange resin in the H + form. An additional reactor is included for illustrating an enzyme-catalyzed system. The conversion achieved is determined using the Flow Injection Analysis technique.

Hybrid organic-inorganic materials: application in oxidative catalysis

Rocha, G M S R O
Fonte: Nova Science Publishers Publicador: Nova Science Publishers
Tipo: Parte de Livro
ENG
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Oxidative catalysis has been and will be playing an important role in the production of large quantities of intermediates. This technology has a great potential for improvement and this has led to a series of better processes, including the development of a great diversity of suitable catalysts. Within these compounds, metal phosphates and phosphonates possessing layered and pillared structures were found to constitute a very good alternative as catalysts to be used in oxidative catalysis. Metal phosphates and phosphonates can be considered as strong inorganic solid acids and much of their catalytic activity has been attributed to the Brønsted acidity of the interlayered hydroxyl groups and to the Lewis acidity of the metal center. Metal phosphates and phosphonates can be obtained at low temperatures, in aqueous media, using soft chemical routes and their preparation is quite accessible if the correct phosphonic acids and phophates are available. These heterogeneous materials are very interesting from the economical as well as from the environmental points of view because of the high yields and short reaction times, easy recovery from the reaction mixtures and the possibility to perform reactions in solvent-free conditions. Due to their particular physical and chemical properties and high versatility...

Hydrolysis of oligosaccharides over solid acid catalysts: a review

Vilcocq, Léa; Castilho, Paula C.; Carvalheiro, Florbela; Duarte, Luís C.
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em //2014 ENG
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Mild fractionation/pretreatment processes are becoming the most preferred choices for biomass processing within the biorefinery framework. To further explore their advantages, new developments are needed, especially to increase the extent of the hydrolysis of poly- and oligosaccharides. A possible way forward is the use of solid acid catalysts that may overcome many current drawbacks of other common methods. In this Review, the advantages and limitations of the use of heterogeneous catalysis for the main groups of solid acid catalysts (zeolites, resins, carbon materials, clays, silicas, and other oxides) and their relation to the hydrolysis of model soluble disaccharides and soluble poly- and oligosaccharides are presented and discussed. Special attention is given to the hydrolysis of hemicelluloses and hemicellulose-derived saccharides into monosaccharides, the impact on process performance of potential catalyst poisons originating from biomass and biomass hydrolysates (e.g., proteins, mineral ions, etc.). The data clearly point out the need for studying hemicelluloses in natura rather than in model compound solutions that do not retain the relevant factors influencing process performance. Furthermore, the desirable traits that solid acid catalysts must possess for the efficient hemicellulose hydrolysis are also presented and discussed with regard to the design of new catalysts.

Óxidos de ferro e suas aplicações em processos catalíticos: uma revisão

Oliveira,Luiz C. A.; Fabris,José D.; Pereira,Márcio C.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 PT
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A review of most of the reported studies on the use of iron oxides as catalyst in specific processes, namely Haber-Bosch reaction, Fischer-Tropsch synthesis, Fenton oxidation and photolytic molecular splitting of water to produce gaseous hydrogen, was carried out. An essential overview is thus presented, intending to address the fundamental meaning, as well as the corresponding chemical mechanisms, and perspectives on new technological potentialities of natural and synthetic iron oxides, more specifically hematite (α-Fe2O3), goethite (α-FeOOH), magnetite (Fe3O4) and maghemite (γ-Fe2O3), in heterogeneous catalysis.

Heterogeneous catalysis afford biodiesel of babassu, castor oil and blends

Carvalho,Lee M. G. de; Abreu,Wiury C. de; Silva,Maria das Graças de O. e; Lima,José Renato de O.; Oliveira,José Eduardo de; Matos,José Milton E. de; Moura,Carla V. R. de; Moura,Edmilson M. de
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2013 EN
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This work describes the preparation of babassu, castor oil biodiesel and mixtures in various proportions of these oils, using alkaline compounds of strontium (SrCO3 + SrO + Sr (OH)2) as heterogeneous catalysts. The mixture of oils of these oleaginous sources was used in the production of biodiesel with quality parameters that meet current legislation. The catalyst was characterized by X-ray diffractometry (XDR), physisorption of gas (BET method), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The viscometric technique was used to monitor the optimization. The transesterification reactions performed using strontium compounds reached conversion rates of 97.2% babassu biodiesel (BB), 96.4% castor oil biodiesel (COB) and 95.3% Babassu/Castor Oil Biodiesel 4:1 (BBCO41).

Ethyl oleate production by means of pervaporation-assisted esterification using heterogeneous catalysis

Figueiredo,K. C. S.; Salim,V. M. M.; Borges,C. P.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
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Pervaporation-assisted esterification of oleic acid and ethanol was investigated by means of heterogeneous acid catalysis with the aim of increasing the ethyl oleate yield. The experimental strategy comprised kinetic tests with Amberlyst 15 Wet (Rohm & Haas), the characterization of hydrophilic Pervap 1000 membrane (Sulzer) and the evaluation of the membrane-assisted reactor. Kinetic tests were carried out to study the effect of temperature, catalyst loading and ethanol/organic acid molar ratio for the esterification of oleic acid and ethanol. The ester yield and initial reaction rate were used as response. The hydrophilic poly(vinyl alcohol) membrane was able to remove water from the reaction medium and, hence, the ester yield was increased. The potential of coupling esterification and pervaporation was demonstrated, with a two-fold increase in the reaction yield of ethyl oleate.

Synthesis and Characterization of LaNiO3, LaNi(1-x)Fe xO3 andLaNi(1-x)Co xO3 Perovskite Oxides for Catalysis Application

Lima,Sania Maria de; Assaf,José Mansur
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2002 EN
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Mixed metal oxides with perovskite-type structure show a great potential to be used in catalysis, electrocatalysis and electronic ceramics. Perovskites oxides catalysts with the composition LaNiO3, LaNi(1-x)Fe xO3 and LaNi(1-x)Co xO3 (x = 0.4 and 0.7) have been synthesized by the precipitation method to be used in the methane reforming to produce hydrogen and synthesis gas. The compounds were characterized by X-ray diffraction, thermogravimetric and differential thermal analysis, inductively coupled plasma atomic emission spectroscopy, surface area measurements, energy dispersive X-ray spectrometry coupled to scanning electron microscopy and temperature programmed reduction. The results showed that a suitable combination of the preparation method with calcination variables (time and temperature) could result in oxides with the desired structure and with important properties at the application point of view in heterogeneous catalysis.

Síntese, caracterização e aplicação de LaSBA-15 e como catalisador para obtenção de biodiesel de soja via rota etílica

Araújo, Larissa Cicianny Luz Ferreira de
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Ciência e Engenharia do Petróleo; Pesquisa e Desenvolvimento em Ciência e Engenharia de Petróleo Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Ciência e Engenharia do Petróleo; Pesquisa e Desenvolvimento em Ciência e Engenharia de Petróleo
Tipo: Dissertação Formato: application/pdf
POR
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Biodiesel is an alternative fuel, renewable, biodegradable and nontoxic. The transesterification of vegetable oils or animal fat with alcohol is most common form of production of this fuel. The procedure for production of biodiesel occurs most commonly through the transesterification reaction in which catalysts are used to accelerate and increase their income and may be basic, acid or enzyme. The use of homogeneous catalysis requires specific conditions and purification steps of the reaction products (alkyl ester and glycerol) and removal of the catalyst at the end of the reaction. As an alternative to improve the yield of the transesterification reaction, minimize the cost of production is that many studies are being conducted with the application of heterogeneous catalysis. The use of nano-structured materials as catalysts in the production of biodiesel is a biofuel alternative for a similar to mineral diesel. Although slower, can esterify transesterified triglycerides and free fatty acids and suffer little influence of water, which may be present in the raw material. This study aimed at the synthesis, characterization and application of nano-structured materials as catalysts in the transesterification reaction of soybean oil to produce biodiesel by ethylic route. The type material containing SBA-15 mesoporous lanthanum embedded within rightly Si / La = 50 was used catalyst. Solid samples were characterized by X-ray diffraction...

Acid-base bifunctional periodic mesoporous metal phosphonates for synergistically and heterogeneously catalyzing CO₂ conversion; Acid-base bifunctional periodic mesoporous metal phosphonates for synergistically and heterogeneously catalyzing CO(2) conversion

Ma, T.Y.; Qiao, S.Z.
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
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Integrating multiple functions into one host for improved catalytic performance is challenging and promising for both catalysis and material science. Herein a new acid–base bifunctional periodic mesoporous titanium phosphonate hybrid material is synthesized by a facile one-pot hydrothermal method, using alendronate sodium trihydrate as a coupling molecule. The new material possesses highly periodic mesopores with a large specific surface area of 540 m2 g–1 and pore volume of 0.43 cm3 g–1, favoring the smooth mass transport of reactants and products during the catalytic reaction. It also has an organic–inorganic hybrid framework with homogeneously incorporated phosphonate groups, in which a large number of accessible acidic P–OH and basic −NH2 sites can, respectively, activate aziridine and CO2, synergistically leading to the high conversion (>99%), yield (98%), and regioselectivity (98:2) for the CO2 cycloaddition reaction. The catalytic activity is better than that of the scarcely reported heterogeneous catalysts for aziridine and CO2 cycloaddition and even comparable to that of the state-of-the-art homogeneous ones. Moreover, being superior to the other catalysts, the metal phosphonate materials can be easily separated and reused repeatedly without activity loss...

Contrôle de l'organisation moléculaire en 2D et 3D par l’utilisation de liaisons hydrogène, de coordination métallique et d'autres interactions

Duong, Adam
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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La stratégie de la tectonique moléculaire a montré durant ces dernières années son utilité dans la construction de nouveaux matériaux. Elle repose sur l’auto-assemblage spontané de molécule dite intelligente appelée tecton. Ces molécules possèdent l’habilité de se reconnaitre entre elles en utilisant diverses interactions intermoléculaires. L'assemblage résultant peut donner lieu à des matériaux moléculaires avec une organisation prévisible. Cette stratégie exige la création de nouveaux tectons, qui sont parfois difficiles à synthétiser et nécessitent dans la plupart des cas de nombreuses étapes de synthèse, ce qui empêche ou limite leur mise en application pratique. De plus, une fois formées, les liaisons unissant le corps central du tecton avec ces groupements de reconnaissance moléculaire ne peuvent plus être rompues, ce qui ne permet pas de remodeler le tecton par une procédure synthétique simple. Afin de contourner ces obstacles, nous proposons d’utiliser une stratégie hybride qui se sert de la coordination métallique pour construire le corps central du tecton, combinée avec l'utilisation des interactions plus faibles pour contrôler l'association. Nous appelons une telle entité métallotecton du fait de la présence du métal. Pour explorer cette stratégie...

Heterogeneous Catalysis on a Disordered Surface

Frachebourg, L.; Krapivsky, P. L.; Redner, S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/06/1995
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We introduce a simple model of heterogeneous catalysis on a disordered surface which consists of two types of randomly distributed sites with different adsorption rates. Disorder can create a reactive steady state in situations where the same model on a homogeneous surface exhibits trivial kinetics with no steady state. A rich variety of kinetic behaviors occur for the adsorbate concentrations and catalytic reaction rate as a function of model parameters.; Comment: 4 pages, gzipped PostScript file

The steady-state of heterogeneous catalysis, studied by first-principles statistical mechanics

Reuter, Karsten; Frenkel, Daan; Scheffler, Matthias
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 04/08/2004
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The turn-over frequency of the catalytic oxidation of CO at RuO2(110) was calculated as function of temperature and partial pressures using ab initio statistical mechanics. The underlying energetics of the gas-phase molecules, dissociation, adsorption, surface diffusion, surface chemical reactions, and desorption were obtained by all-electron density-functional theory. The resulting CO2 formation rate [in the full (T, p_CO, p_O2)-space], the movies displaying the atomic motion and reactions over times scales from picoseconds to seconds, and the statistical analyses provide insights into the concerted actions ruling heterogeneous catalysis and open thermodynamic systems in general.; Comment: 4 pages including 3 figures, Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.html

Global Solutions for a Class of Heterogeneous Catalysis Models

Bothe, Dieter; Köhne, Matthias; Maier, Siegfried; Saal, Jürgen
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/10/2015
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We consider a mathematical model for heterogeneous catalysis in a finite three-dimensional pore of cylinder-like geometry, with the lateral walls acting as a catalytic surface. The system under consideration consists of a diffusion-advection system inside the bulk phase and a reaction-diffusion-sorption system modeling the processes on the catalytic wall and the exchange between bulk and surface. We assume Fickian diffusion with constant coefficients, sorption kinetics with linear growth bound and a network of chemical reactions which possesses a certain triangular structure. Our main result gives sufficient conditions for the existence of a unique global strong $L^2$-solution to this model, thereby extending by now classical results on reaction-diffusion systems to the more complicated case of heterogeneous catalysis.; Comment: 30 pages

Mononuclear Ruthenium Complexes and their Application in Homogeneous and Heterogeneous Catalysis

Vaquer Malia, Lydia
Fonte: [Barcelona] : Universitat Autònoma de Barcelona, Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2011 ENG
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La tesis presentada es un estudio basado en la síntesis, caracterización espectrocópica y electroquímica y aplicaciones en catálisis de nuevos complejos mononucleares de rutenio con una amplia variedad de ligandos polipiridílicos. La influencia de las propiedades electrónicas de los ligandos coordinados al centro metálico sobre las propiedades redox de los complejos resultantes y su comportamiento en catálisis de oxidación ha sido estudiada y racionalizada. De la familia de complejos Ru-OH2 sintetizados y estudiados, unos pocos fueron seleccionados para desarrollar sistemas más complejos y poder ser utilizados para (a) catálisis heterogénea (obteniendo sistemas catalíticos fácilmente reciclables) y (b) catálisis supramolecular (para poder llevar a cabo oxidaciones regioselectivas de sustratos orgánicos). Para el desarrollo de catálisis heterogénea, nanopartículas magnéticas (NPs) de óxidos de hierro fueron seleccionadas como soporte y los sistemas resultantes NP-Ru presentaron una buena dispersión en disolventes orgánicos y pudieron ser fácilmente separados y reutilizados, obteniendo así un sistema casi-homogéneo, en el que las ventajas de ambos procesos homogéneo y heterogéneo fueron combinados. Como último capítulo de la tesis...

A ReaxFF Reactive Force-field for Proton Transfer Reactions in Bulk Water and its Applications to Heterogeneous Catalysis

van Duin, Adri C. T.; Zou, Chenyu; Joshi, Kaushik; Bryantsev, Vyascheslav; Goddard, William A.
Fonte: Royal Society of Chemistry Publicador: Royal Society of Chemistry
Tipo: Book Section; PeerReviewed Formato: application/pdf
Publicado em 02/12/2013
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We have developed a ReaxFF reactive force-field description for bulk water and for proton transfer in the aqueous phase. This ReaxFF potential was parameterized exclusively against quantumchemical (QM) data, describing a broad range of intra- and intermolecular water interactions, including H–H, HO–OH and O=O bond dissociation energies, charge distributions, angle bending energies, binding energies for [H_2O]2–35-clusters, H-transfer reactions pathways in H_3O^+/H_2O, [H_2O]n and HO−/H_2O-clusters and ice densities and cohesive energies. We find good agreement between ReaxFF and QM for all these cases. We found that this QM-based ReaxFF potential gives a good description of bulk water phases and proton migration, reproducing experimental density, radial distribution and diffusion data, while it overestimates proton diffusion in the OH−/water system. We anticipate that this ReaxFF water description, in combination with ongoing ReaxFF-work on amines, carboxylic acids, phosphates and inorganic materials, should be highly suitable for simulating biochemical reactions involving enzymes and DNA. Furthermore, this potential can be used to simulate water reactions and proton diffusion on metal and metal oxide surfaces, opening up applications to catalysis...

Synthesis of Fruity Flavor Esters: An Experiment for Undergraduate Courses within one of the Principles of Green Chemistry; Síntese de Ésteres de Aromas de Frutas: Um Experimento para Cursos de Graduação dentro de um dos Princípios da Química Verde

Camila A. Oliveira; Universidade Federal do Rio de Janeiro; Aline C. J. Souza; Universidade Federal do Rio de Janeiro; Ana Paula B. Santos; Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro-DC; Bárbara V. Silva; Universidade Federa
Fonte: Revista Virtual de Química Publicador: Revista Virtual de Química
Tipo: ; Formato: application/pdf
Publicado em 08/02/2014 PT
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The esters are among the classes of organic substances responsible for the pleasant odor of flowers and fruits. The synthesis of these substances occurs through the reaction between carboxylic acids and alcohols, usually catalyzed by BrÖnsted-Lowry acid. This work presents the results of different methods of esterification using homogeneous catalysis like sulfuric acid and heterogeneous catalysis with commercial sulfonic resin (Amberlyst 35) and montmorilonite clay. All reactions were carried out with heating under reflux and repeated with use of the system Dean-Stark to remove water produced in the reaction. The use of Dean-Stark moves the equilibrium to the formation of the products and, consequently, reduces significantly the reaction time. The heterogeneous catalysts proved  to be advantageous relatively to the use of sulfuric acid since the process of isolation is easier and  provides an approach of Green Chemistry in Undergraduate experimental classes. DOI: 10.5935/1984-6835.20140012; Os ésteres estão entre as classes de substâncias orgânicas responsáveis pelo odor agradável de flores e frutos. A síntese destas substâncias ocorre através da reação entre ácidos carboxílicos e alcoóis, geralmente catalisadas por ácidos de Bronsted-Lowry. Este trabalho apresenta os resultados de diferentes métodos de esterificação...

Esterification and transesterification assisted by microwaves of crude palm oil: Heterogeneous catalysis

Mazo,P.C.; Ríos,L.A.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 EN
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The principal objective of this study was to obtain alkyl ester from crude palm oil (CPO), using microwaves like heating source, in a process of two stages by means of heterogeneous catalysis; the first stage (esterification), was made using Dowex 50X2, Amberlyst 15 and Amberlite IR-120 resins catalysts, to diminish the acid value of the oil, avoiding the soap formation and facilitating the separation of the phases. The second stage (transesterification) was made using potassium carbonate catalyst. The behavior in the crystallization of the product using differential scanning calorimetry, cloud point ASTM D2500 (2005) and pour point ASTM D97 (2005) was evaluated. The obtained biofuels fulfill the requirements of the American standards for biodiesel and the propose methodology for the synthesis presents environmental advantages and of increase in the reactivity, as opposed to the traditional methods of heating.