UTN- FRC -Producción Académica de Investigación y Desarrollo

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Author: search.filters.author.Ledesma, Brenda Cecilia

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    Novel and simple one-pot method for the synthesis of titanium modified-CMK-3 applied in oxidative desulfutization of refractor y organosulfur compounds
    (Sociedad Mexicana de Materiales / Materials Research Society, 2018) Rivoira, Lorena Paola; Ledesma, Brenda Cecilia; Beltramone, Andrea Raquel
    Ti-CMK-3 carbon mesoporous was prepared using a novel synthesis method. This new method avoids the hard template synthesis used commonly. The method developed here, allows reducing time, energy consumption and cost. Our primary aim in this work is to evaluate the ODS activity of the Ti-modified mesoporous carbon CMK-3, synthesized by the short time method, in order to achieve total removal of sulfur compounds from diesel fuel. The catalytic oxidation of the sulfur compound with hydrogen peroxide was carried out in a glass batch reactor, equipped with a magnetic stirrer, a thermometer and a condenser. In a typical run, the solid catalyst (60 mg) was suspended under stirring (750 rpm) in 20 mL of a solution of 500 ppm of S as DBT (or other) in acetonitrile. Then, appropriate amount of 30% aqueous H2O2 was added at constant temperature. The experiments were performed in a three-phase liquid-liquid-solid (L (oil) –L (solvent) –S (catalyst)) system, acetonitrile was used as solvent and dodecane as oil phase. Solution samples were recovered at various times. The products were analyzed by GC HP 5890 Series II with a HP-5 column and connected to FID and PFPD detectors, after filtration and eventually decantation step. The products were confirmed using a Shimadzu GCMS. Structural and textural characterization of the titanium modified-mesoporous carbon was performed by N2 adsorption, XRD, UV-Vis-DRS, XPS, Raman spectroscopy and TEM. The characterization results indicated that the textural and structural properties of the material synthesized by the short time method are comparable with the properties of the material prepared by the hard template method. Ti modified-mesoporous carbon was synthesized by different methods in order to prepare catalysts to be tested in the oxidative desulfurization (ODS) of sulfur compounds. The good performance and stability of the catalyst prepared using a novel synthesis method was attributed to well dispersed anatase nanospecies over the high area mesoporous carbon. Main advantage of the present study is the reduction of time and cost in the synthesis of the new material and the applicability for ODS reactions.
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    Novel and simple one-pot method for the synthesis of Ti02 modified-CMK-3 applied in oxidative desulfurization of refractory organosulfur compounds.
    (Universidad Tecnológica Nacional Regional Córdoba., 2018) Rivoira, Lorena Paola; Ledesma, Brenda Cecilia; Juárez , Juliana María; Beltramone , Andrea Raquel
    Ti-CMK-3 carbon mesoporous was prepared using a novel synthesis method. This new method avoids the hard template synthesis used commonly. The precursors of silicon, carbon and titanium are incorporated together with the other components during the only step of the synthesis. The method developed here, allows reducing time and energy consumption by 60% and thus, the cost of the overall process of synthesis. Structural and textural characterization of the titanium modified-mesoporous carbon was performed by N2 adsorption, XRD, UV–Vis DRS, XPS, Raman spectroscopy and TEM. The characterization results indicated that the textural and structural properties ofthe material synthesized by the short time method are comparable with the properties of the material prepared by the hard template method. Ti modified-mesoporous carbon was synthesized by dif- ferent methods in order to prepare catalysts to be tested in the oxidative desulfurization (ODS) of sulfur com- pounds. The catalyst prepared by the one-pot method is capable to oxidize high amount of sulfur (2000 ppm) in only 30 min of reaction time at 60–80 °C. The good performance and stability of the catalyst prepared using a novel synthesis method was attributed to well dispersed anatase nanospecies over the high area mesoporous carbon. Main advantage of the present study is the reduction of time and cost in the synthesis of the new material and the applicability for ODS reactions.
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    Síntesis directa de CMK-3 modificada con Ti, como soporte de Ir aplicado a reacciones de hidrodenitrogenacion.
    (Univesidsad Tecnológica Nacional., 2018) Ledesma, Brenda Cecilia; Juárez, Juliana María; Beltramone , Andrea Raquel; Juárez, Juliana María
    En el presente trabajo se sintetizó Ti-CMK-3 mediante un nuevo método de síntesis, en el cual se evita la utilización de un molde, con el fin de reducir el tiempo, el consumo de energía y por ende el costo. La caracterización estructural y superficial del catalizador se realizó mediante adsorción de N2, XRD, UV-Vis DRS, espectroscopía Raman y TEM. Los resultados de la caracterización indicaron que las propiedades texturales y estructurales del material sintetizado son comparables con las propiedades del material preparado por el método tradicional. El catalizador Ir-Ti-CMK-3 obtenido fue activo y selectivo para la reacción de hidrodenitrogenación (HDN) del indol. La principal ventaja del presente estudio es la reducción de tiempo y costo de la síntesis, simultáneamente con la aplicabilidad en las reacciones de Hidrotratamiento (HDT)
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    Direct Synthesis of ordered mesoporous carbon as support of Ir-Catalyst and its application in hydrodenitrogenation of indole.
    (Univesidsad Tecnológica Nacional., 2018) Ledesma, Brenda Cecilia; Juárez , Juliana María; Beltramone, Andrea Raquel; Juárez , Juliana María
    An ordered mesoporous carbon (OMC) modified with titania was prepared using a novel and shorter synthesis method. OMC was successfully synthesized by the carbonization of the silica/TEOT/triblock copolymer/sucrose composite in the presence of sulfuric acid. This novel material was modified with the incorporation of nanoparticles of Iridium. Structural and textural characterization of the catalyst was performed by means of N2 adsorption, XRD, UV–Vis–DRS, Raman spectroscopy, XPS, TEM and H2 Chemisorption. The characterization results indicated that the textural and structural properties of the support synthesized by the short time method are comparable with the properties of the support prepared by the hard template method. Ir-Ti-OMC catalyst obtained by short time synthesis was active and selective in the hydrogenation of indole. Main advantage of the present study is the reduction of time and cost in the synthesis of the new material and the applicability for HDT reactions.
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    Sulfur elimination by ODSwith titanium-modified SBA-16.
    (Univesidsad Tecnológica Nacional., 2015) Rivoira , Lorena Paola; Vallés , Verónica Alejandra; Ledesma, Brenda Cecilia; Martínez , María Laura; Anunziata , Oscar Alfredo; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Martínez , María Laura; Ledesma, Brenda; Vallés , Verónica Alejandra
    Nanostructured carbon CMK-3 and mesoporous silica SBA-15 modified with Fe by using different sources of Fe, were used in the oxidative desulfurization (ODS) of dibenzothiophene (DBT) as a model sulfur compound. Fe-CMK-3 and Fe-SBA-15 were prepared by wetness impregnation using FeCl3.6H2O and FeNO3.9H2O as different sources of Fe. A solution of FeCl3.6H2O/ FeNO3.9H2O in ethanol was mixed with the corresponding material solution (CMK-3 or SBA-15) at room temperature. The solution was placed in a rotary evaporator to remove excess of ethanol at about 333 K and 60 rpm. Afterwards, the sample was dried at 373 K for 18 h and was thermally treated in a dynamic inert (N2) atmosphere. The percentage of Fe has been 2 wt.% with respect to carbon in the final FeCl3-CMK-3 and FeNO3-CMK-3 material. Four samples modified with Fe have been prepared and were characterized by XRD, FTIR, XPS, BET, TEM and SEM. These studies indicated that it was possible to obtain a CMK-3 replica successfully from SBA-15, using sucrose as a carbon precursor. Wide angle XRD pattern of the sample modified with FeCl3.6H2O implies the formation of the magnetite phase in the silica channels. The nanomaterial area is significantly smaller with the incorporation of the metal, SBA-15 and CMK-3`s characteristic structure is maintained after the metal is within the host, in agreement with the XRD studies. The catalytic activity was improved when the nanoporous materials were modified with Fe. The nanoporous carbon modified with FeCl3.6H2O was the most active catalyst for ODS of DBT, using hydrogen peroxide (H2O2) as oxidant and acetonitrile as solvent. 100% of DBT elimination was attained at a short time in mild conditions.
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    CMK-3 modificada con titanio obtenida mediante un novedoso y rápido método de síntesis aplicada en la desulfuración oxidativa de compuestos organosulfurados.
    (Univesidsad Tecnológica Nacional., 2018) Rivoira , Lorena Paola; Ledesma, Brenda Cecilia; Juárez , Juliana María; Beltramone , Andrea Raquel; Juárez , Juliana María; Ledesma, Brenda
    El nanomoldelado de materiales ha sido el único método para crear materiales mesoporosos de carbono, utilizando plantillas inorgánicas (Ezzeddine et al., 2016). Involucra una última etapa donde se elimina el agente plantilla, lo cual lo hace complicado, largo y de elevado costo. Recientemente Ledesma et al. (2017) demostraron la posibilidad de un método de síntesis más corto para obtener CMK-3 modificada con Ti incorporando las especies de Ti directamente en la estructura del carbón mesoporoso utilizando Ti-SBA-15 como agente plantilla. En la reacción de ODS ocurre la oxidación de aquellos compuestos de S más refractarios en la HDS, utilizando de un agente oxidante en presencia de un catalizador (Subhan et al., 2012). Es necesario agregar un solvente polar al sistema, capaz de extraer las moléculas de S desde la fase diesel para que pueda estar en contacto con el agente oxidante (H2O2, polar) y el catalizador. En el presente trabajo se evalúa la actividad en la ODS de carbón mesoporoso CMK-3 modificado con Ti, sintetizado mediante un novedoso método más corto.
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    Experimental Desing Optimization of the tetralin Hydrogenation over Ir-Pt-SBA-15.
    (Univesidsad Tecnológica Nacional, 2016) Vallés , Verónica Alejandra; Ledesma, Brenda Cecilia; Rivoira , Lorena Paola; Cussa , jorgelina; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Cussa , jorgelina; Rivoira , Lorena Paola; Ledesma, Brenda
    Experiment design-response surface methodology (RSM) is used in this work to model and optimize two responses in the hydrogenation of tetralin to decalin using bimetallic Ir–Pt-SBA-15 catalyst. In this study, we analyze the influence of the nature of the catalyst (metal molar fraction and metal loading), the catalyst/substrate ratio and the temperature of the reaction as factors for the design. The responses analyzed were conversion at 3 h and at 5 h of reaction time. The response surfaces were obtained with the Box–Behnken design, finding the best combination between the reaction parameters that allowed optimizing the process. By applying the statistic methodology, the higher levels of the two objective functions were obtained employing the catalyst with 1 wt.% of iridium and 0.7–0.8 wt.% of platinum; the optimal ratio between mass of catalyst and mole of tetralin was 17–19 g/mol and temperature between 200 and 220 ◦C.
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    Hidrogenación de tetralin sobre Ir-Pt-SBA-15. Parte 2: Optimización por Diseño de Experimentos.
    (Univesidsad Tecnológica Nacional, 2015) Vallés , Verónica Alejandra; Ledesma, Brenda Cecilia; Rivoira , Lorena Paola; Cussa , jorgelina; Anunziata , Oscar Alfredo; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Cussa , jorgelina; Rivoira , Lorena Paola; Ledesma, Brenda
    La Metodología Diseño de Experimentos - Superficie de Respuesta – se utiliza en este trabajo para modelar y optimizar 2 respuestas en la reacción de hidrogenación de tetralin a decalin usando un catalizador bimetálico Ir-Pt-SBA-15. En este estudio se analizó la influencia de la naturaleza del catalizador, la relación catalizador/sustrato y la temperatura de reacción como factores del diseño. Las respuestas analizadas fueron conversión a 3 y 5 horas Las Superficies de Respuesta fueron obtenidas mediante un diseño Box-Behnken a fin de encontrar la mejor combinación de los distintos parámetros para optimizar el proceso. La metodología estadística aplicada indica que las conversiones más altas de ambas respuestas, a 3 y 5 horas, se obtienen trabajando en el siguiente rango: Catalizador: 1% Ir y 0.7-0.9 %(p/p) Pt; Relación: 17-19 g cat/ mol TL y Temperatura: 200-220°C.
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    Hidrogenación de tetralin sobre Ir-Pt-SBA-15. Parte 1: Síntesis, caracterizacíon y actividad catalítica.
    (Univesidsad Tecnológica Nacional, 2015) Vallés , Verónica Alejandra; Ledesma, Brenda Cecilia; Rivoira , Lorena Paola; Cussa , jorgelina; Anunziata , Oscar Alfredo; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Cussa , jorgelina; Rivoira , Lorena Paola
    Se estudia aquí la hidrogenación de tetralin a decalin utilizando un catalizador bimetálico Ir-Pt SBA-15. En esta Parte se describe la síntesis de los catalizadores, la preparación de la matriz de SBA 15 y el método de co-impregnacion mediante el cual se incorporaron los metales en diferentes proporciones y carga total metalica. Los catalizadores fueron caracterizados por XRD, TEM, análisis fisicoquimicos, XPS, SEM y EDX. En la Parte 2 de este trabajo se analizará la influencia de la naturaleza del catalizador, la relación catalizador sustrato y la temperatura de reacción como factores de un Diseño de Experimentos para optimizar el proceso.
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    Síntesis y caracterización de un catalizador soportado iridio/platino-SBA-15 para su aplicación en la Hidrogenación de Tetralin.
    (Univesidsad Tecnológica Nacional, 2014) Vallés , Verónica Alejandra; Ledesma, Brenda Cecilia; Rivoira , Lorena Paola; Cussa , jorgelina; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Cussa , jorgelina; Rivoira , Lorena Paola; Ledesma, Brenda
    In this paper the effect of the dispersion of noble metals Ir and Pt and interaction with the SBA-15 support was studied by relating them to the catalytic activity of the catalyst in the hydrogenation reaction of Tetralin using a Parr reactor at 250°C and 15 atm. With this objective Ir/Pt-SBA-15 modified catalysts were synthesized with different % of Ir and Pt. The mesostructure of SBA-15 support gives a relatively high thermal stability and proper pore diameter can converts large molecules such as those present in the liquid fuels. The support was prepared by the sol-gel method. The catalytic site was obtained using incipient co impregnation method. The material was characterized by X-ray diffraction (XRD) and TEM). The metal dispersion was calculated by H2 chemisorption and TEM. Iridium / Platinum particles (d = 2,0-4,0 nm) homogeneously dispersed were obtained with a dispersion of more than 60%.