78 research outputs found

    Kinetic study of methanol dehydration over Zro2 supported-activated carbons

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    The growing concerns about climate change and energy consumption have been the driving force in seek of alternative fuels such as DME, mainly produced via methanol dehydration over a solid acid catalyst. The use of activated carbons for this aim has been little studied up to date. Only a few studies can be found in the literature, reporting all of them materials with a low thermal stability of the acid surface groups, which results into a fast deactivation of the catalyst. In this work, the preparation of activated carbons via chemical activation with phosphoric acid, their modification with different ZrO2 loads, and their application as methanol dehydration catalysts have been studied. The catalytic results showed that the best methanol conversion and selectivity towards DME were achieved with the activated carbon prepared with an impregnation mass ratio value (H3PO4 /precursor) of 2 and an activation temperature of 800 ºC, loaded with a 7 % (wt) of ZrO2 . This catalyst exhibits high steady state methanol conversion values even at temperatures as high as 400 ºC (XCH3OH= 80%, 0.1 g·s/μmol, PCH3OH= 0.08 atm in helium), keeping a selectivity to DME higher than 96%. The effect of oxygen in the reaction atmosphere was also analysed. In this sense, an increase of 15 % in the DME yield was obtained when using air instead of helium as reaction atmosphere (350 ºC, 0.1 g·s/μmol, PCH3OH= 0.04 atm). A kinetic study has been carried out on this catalyst in which two mechanisms (Eley Rideal and Langmuir Hinshelwood) for methanol dehydration have been analysed. The models proposed also consider the presence of oxygen in the reaction media.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. MINECO (CTQ2015-68654-R). MECD (FPU13/02413)

    Osmium impregnated on magnetite as a heterogeneous catalyst for the syn-dihydroxylation of alkenes

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    A new catalyst derived from osmium has been prepared, fully characterized and tested in the dihydroxylation of alkenes. The catalyst was prepared by wet impregnation methodology of OsCl3·3H2O on a commercial micro-magnetite surface. The catalyst allowed the reaction with one of the lowest osmium loadings for a heterogeneous catalyst and was selective for the monodihydroxylation of 1,5-dienes. Moreover, the catalyst was easily removed from the reaction medium by the simple use of a magnet. The selectivity of catalyst is very high with conversions up to 99%. Preliminary kinetics studies showed a first-order reaction rate with respect to the catalyst.This work was supported by the Spanish Ministerio de Economía y Competitividad (CTQ2011-24151). J. M. P. thanks the M.E.C. for a fellowship through the FPI program

    Multicomponent Azide-Alkyne Cycloaddition Catalyzed by Impregnated Bimetallic Nickel and Copper on Magnetite

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    A new bimetallic catalyst derived from nickel and copper has been used successfully for the first time in the multicomponent reaction of terminal alkynes, sodium azide, and benzyl bromide derivatives. The presence of both metallic species on the surface of magnetite seems to have a positive and synergetic effect. The catalyst loading is the lowest ever published for a catalyst of copper anchored on any type of iron support. The catalyst could be easily removed from the reaction media just by magnetic decantation and it could be reused up to ten times without any negative effect on the initial results

    Imaginarios sociales frente al docente masculino en educación inicial en el distrito de Comas, Lima, Perú

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    This investigation seeks to interpret the social imaginaries about Initial Education male teacher on Comas district, Lima, Perú on 2018. This study pose since qualitative focus, phenomenological design through description of narratives on that community, with semi-estructured interview, getting this information about representations or thoughts socially accepted and extended that are build aroud a rare situation on this education level, so that it offers evidence about the influence of those peceptions in the exercise and teaching practice.Esta investigación busca interpretar la realidad de los imaginarios sociales frente al docente masculino en Educación Inicial en el distrito de Comas en la ciudad de Lima, Perú, en el año 2018. Dicho estudio se plantea desde el enfoque cualitativo, con diseño fenomenológico a través de la descripción de las narrativas que se tejen en la comunidad antes mencionada, se parte de las entrevistas semiestructuradas, que develan información acerca de las representaciones o pensamientos socialmente aceptados y extendidos que se construyen en torno a una situación poco común en este nivel de educación, de modo que ofrece así evidencia de la influencia de dichas percepciones en el ejercicio y práctica docente

    Palladium(II) oxide impregnated on magnetite as a catalyst for the synthesis of 4-arylcoumarins via a Heck-arylation/cyclization process

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    Heck-arylation/cyclization was achieved using heterogeneous palladium(II) oxide impregnated on magnetite catalyst (2.5 mol%) with a lower catalyst loading than that reported for similar processes. Ethanol was used as a non-toxic and bio-renewable solvent. Good yields were afforded using a broad range of substrates (40–98%). The catalyst could be partially recycled, and analyses confirmed the almost total reduction of palladium(II) oxide to palladium(0) as well as the iodine poissoning effect, which is the main barrier to complete recyclability.The authors thank the Spanish Ministerio de Economía y Competitividad (MICINN; CTQ2011-24151), University of Alicante, Irish Research Council (RC) and Science Foundation Ireland (SFI/12/IP/1315 and SFI/12/RC/2275). J. M. P. thanks the MICINN (FPI program) for her fellowship

    Stories of teaching innovation

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    Desde la remodelación de los planes de estudio en la década de 1990, el profesorado que del Departamento de Didáctica y Organización Educativa de la Universidad que impartimos las asignaturas del ámbito de la Tecnología Educativa en las licenciaturas de Pedagogía y Psicopedagogía y en las diplomaturas de Educación Social y Magisterio, nos hemos caracterizado por buscar una actualización permanente tanto de los contenidos como de la forma de impartirlos. En esta trayectoria de búsqueda de nuevas formas de representar el conocimiento e interactuar con el alumnado hemos formado un grupo de innovación docente en el que participamos profesores y profesoras de 13 asignaturas de las facultades de Pedagogía, Formación del Profesorado y Bellas Artes de la misma universidad. La primera actuación de este grupo ha sido poner en marcha el proyecto de innovación docente INDAGA-T (Favoreciendo el aprendizaje autónomo y colaborativo a través de la indagación y la utilización de tecnologías digitales), que está financiado por la Universidad. La finalidad principal del proyecto es contribuir a formar licenciados universitarios con un alto grado de autonomía intelectual, creatividad, colaboración y predisposición para arriesgarse a seguir aprendiendo en su vida personal y profesional. Para conseguir esta finalidad estamos desarrollando un enfoque de formación que sigue un planteamiento construccionista y que, centrado en favorecer la creación de experiencias de aprendizaje por parte de los estudiantes, utiliza una sistema de gestión del aprendizaje digital como complemento y ampliación de los roles y las experiencias de profesores y estudiantes que quieren ser educadores. En este artículo, además de presentar las características del proyecto de formación e innovación docente INDAGA-T, nos centramos en el relato de cómo cada uno de nosotros estamos llevando a la práctica esta experiencia de formación, haciendo especial hincapié en nuestro proceso de aprendizaje y las visiones del alumnado. El seguimiento de una perspectiva narrativa de investigación nos permite construir una relación polivocal en la que se reflejan las diferentes maneras de construir una innovación.Desde a remodelação dos planos de estudo da década de 90, os professores e professoras do Departamento de Didática e Organização Educativa da Universidade que lecionamos as disciplinas de Pedagogia e Psicopedagogia nos cursos de Educação Social e Magistério, nos caracterizamos por buscar uma atualização permanente tanto dos conteúdos como da forma de trabalhá-los. Nesta trajetória de busca de novas formas de representar o conhecimento e interagir com os alunos, formamos um grupo de inovação docente no qual participam professores e professoras de 13 disciplinas das faculdades de Pedagogia, Formação do Professorado e Belas Artes da universidade. A primeira atuação deste grupo foi pôr em marcha o projeto de inovação docente INDAGA-T (favorecendo a aprendizagem autônoma e colaborativa através da indagação e da utilização das tecnologias digitais), que está financiado pela Universidade. A finalidade principal do projeto é contribuir na formação de licenciados universitários com um alto grau de autonomia intelectual, criatividade, colaboração e predisposição para arriscar-se a seguir aprendendo na sua vida pessoal e profissional. Para conseguir esta finalidade estamos desenvolvendo um enfoque construcionista de formação que, centrado em favorecer a criação de experiências de aprendizagem por parte dos alunos, utiliza um sistema de gestão da aprendizagem digital como complemento e ampliação dos papéis e das experiências de profesoores e estudantes que queiram ser educadores. Na presente comunicação, além de apresentar as características do projeto de formação e inovação docente INDAGA-T, relatamos como estamos transferindo à prática esta experiência de formação, com uma ênfase especial no nosso processo de aprendizagem e nas visões dos alunos. A adoção de uma perspectiva narrativa de pesquisa nos permite construir uma relação polivocal na qual se refletem distintas formas de construir uma inovação.Since the remodeling of the curricula in the 1990s, the teachers of the Department of Teaching and Educational Organization of the University, that we impart the subjects in the field of educational technology in the bachelor of Pedagogy and Educational Psychology, and in the professions of Social Education and Teaching, have characterized by search for a permanent update of both content and the way of administering them. In this path of search for new ways to represent knowledge and interact with the students we have formed a group of educational innovation in which we participate teachers from 13 subjects of the faculties of education, teacher training and Fine Arts at the same university. The first performance of this group has been set in motion the teaching innovation project INDAGA-T (favoring the autonomous learning and collaborative through the inquiry and the use of digital technologies), which is funded by the University. The main purpose of the project is to contribute to form university graduates with a high degree of intellectual autonomy, creativity, collaboration, and predisposition to risk to continue learning in their personal and professional life. To achieve this purpose we are developing a training approach that follows a constructionist approach and focused on fostering the development of learning experiences on the part of students, uses a system of management of the digital learning as a complement and expansion of the roles and the experiences of teachers and students who want to become educators. In this article, in addition to presenting the characteristics of the project training and teaching innovation INDAGA-T, we focus on the story of how each of us we are in the process of implementing this training experience, with special emphasis in our process of learning and the visions of the student body. The follow-up of a narrative perspective of research allows us to construct a relationship polivocal to reflect the different ways to build an innovation

    Valoración e interpretación de la intervención sobre la historia social única electrónica

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    21 páginas.Capítulo incluido en el libro: Informe de Evaluación del Proyecto RESISOR "Regional Single Social Record". M.ª Dolores Muñoz de Dios y José Ignacio García Pérez (autores). Sevilla: Universidad Internacional de Andalucía, 2019. ISBN 978-84-7993-344-9. Enlace: http://hdl.handle.net/10334/3938. En este capítulo se muestra la fundamentación que rige la acción de valoración e interpretación de la intervención sobre la HSUE como actividad de evaluación para el Proyecto RESISOR. Con ella se expone la estructura de trabajo realizada que se ha basado en los Grupos de Discusión como técnica de investigación desarrollada, mostrando la configuración y perfiles de los grupos, así como los resultados principales obtenidos según las categorías de análisis estipuladas en función de los objetivos planteados

    Impregnated palladium on magnetite as catalyst for direct arylation of heterocycles

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    Palladium impregnated on magnetite is an efficient, cheap and easy to prepare catalyst for the direct arylation of heterocycles. Good yields are afforded under relatively mild conditions and a broad substrate scope is evident. The catalyst is regioselective in many cases, affording arylated products, at the C2- or C3-position (depending of the heterocycle used). The methodology can be extended to prepare chromenes through an intramolecular direct arylation reaction. Some evidence is provided for two catalyst deactivation pathways, which prevents efficient recycling.The authors thank the Irish Research Council (RC), Science Foundation Ireland (SFI/12/IP/1315 and SFI/12/RC/2275), Spanish Ministerio de Economía y Competitividad (MICINN; CTQ2011-24151, University of Alicante and MICINN FPI program (JMP)
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