143 research outputs found

    Revalorización y difusión del patrimonio bibliográfico histórico-químico presente en las bibliotecas españolas

    Get PDF
    Presenta el proyecto cuyo objetivo es la puesta en valor de los fondos antiguos relevantes para el estudio de la historia de la química, que se encuentran en la Biblioteca Histórica “Marqués de Valdecilla” de la Universidad Complutense de Madrid, en las bibliotecas pertenecientes al Consejo Superior de Investigaciones Científicas y en la Biblioteca Nacional de España. El proyecto consiste en la elaboración de un catálogo razonado que incluya la totalidad de los títulos previamente identificados, los cuales abarcarían todos los aspectos de la química y temas estrechamente relacionados, proporcionando un enlace al texto completo y a la ficha bibliográfica. Todo ello conforma la “Biblioteca Histórica Química Virtual”, accesible a través de la web del Instituto de Catálisis y Petroleoquímica del CSIC. Particularmente significativa es la inclusión de obras escritas en español, tanto originales como traducidas, de gran importancia en la historia de la química española. A continuación se muestra una pequeña selección, centrada principalmente, aunque no de manera exclusiva, en las obras conservadas en la Biblioteca Histórica de la Univesidad Complutense

    Compuestos relacionados con la diimida de silicio, método de obtención, y su aplicación en la preparación de un material poroso amorfo

    Get PDF
    Compuestos relacionados con la diimida de silicio, método de obtención, y su aplicación en la preparación de un material poroso amorfo. La presente invención se refiere a un compuesto de fórmula general: SixM1-xNyHz donde M se refiere al menos a un elemento del grupo formado por germanio, aluminio y galio; x está comprendido entre 0 y 0.5; y está comprendido entre 2 y 4; y z está comprendido entre 2 y 8; dicho compuesto conteniendo enlaces entre los átomos de silicio y átomos de nitrógeno y entre el elemento M y los átomos de nitrógeno. Asimismo, la presente invención se refiere a un método de obtención del compuesto mediante reacción de amonolisis con los compuestos precursores en líquido iónico y amoniaco gaseoso a una temperatura comprendida entre -15ºC y 200ºC. Otro objeto de la invención es el método de preparación de un material poroso amorfo a partir del compuesto descrito, así como el propio material y sus múltiples usosPeer reviewedConsejo Superior de Investigaciones CientíficasB1 Patente sin examen previ

    Vectores energéticos químicos basados en carbono: Combustibles sintéticos y biocarburantes

    Get PDF
    Vectores energéticos químicos basados en carbono: Combustibles sintéticos y biocarburantes

    Zeolites and ordered porous solids: fundamentals and applications

    Full text link
    Pérez Pariente, J.; Martínez Sánchez, MC. (2011). Zeolites and ordered porous solids: fundamentals and applications. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/11205Archivo delegad

    Procedimiento de aplicación de sepiolitas básicas como catalizadores en reacciones de condensación de Knoevenagel

    Get PDF
    Referencia OEPM: P8904192.-- Fecha de solicitud: 12/12/1989.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).El procedimiento de invención se refiere a la aplicación de sepiolitas básicas como catalizadores en reacción de condensación de Knoevenagel. Las sepiolitas empleadas se obtienen mediante modificación de la sepiolita natural con iones alcalinos o alcalinotérreos. Estos catalizadores poseen una elevada área superficial y un elevado volumen de poro.Peer reviewe

    Síntesis de zeolita beta

    Get PDF
    Referencia OEPM: P9501552.-- Fecha de solicitud: 01/08/1995.-- Titular: Universidad Politécnica de Valencia (UPV).En la presente invención se reivindica un nuevo método de síntesis de zeolita Beta, caracterizado porque en la preparación de la mezcla de síntesis se evita la presencia de cationes alcalinos. La zeolita Beta obtenida se caracteriza por su pequeño tamaño de cristal, su capacidad de formar suspensiones coloidales estables y porque su calcinación permite obtener la forma ácida sin recurrir a procesos de intercambio catiónico. Se reivindica también el uso del material obtenido en procesos catalíticos de transformación de hidrocarburos, para preparación de membranas zeolíticas y como activador de otras síntesis de zeolitas. El método consiste en el calentamiento a 363-473K de una mezcla de reacción que contiene una fuente de silicio, una fuente de aluminio, un catión orgánico director de estructura como hidróxido y agua, evitándose la presencia de cationes alcalinos. Se obtiene una suspensión coloidal de zeolita Beta de la que puede separarse la zeolita.Peer reviewe

    Template-controlled acidity and catalytic activity of ferrierite crystals

    Get PDF
    A synthesis strategy to tailor the acid sites location in ferrierite crystals has been developed. The zeolite catalysts were synthesised in fluoride medium using different combinations of organic structure directing agents (SDAs) in the absence of inorganic cations. Therefore, the negative charge associated to the incorporation of aluminium to the framework was compensated exclusively by the positive charge of the organic SDAs. In this way, Al sitting in the zeolite framework was driven by the specific location of the different SDA molecules within the zeolite void volume. Following this synthesis strategy, it has been found that the distribution of strongly acidic hydroxyl groups in the proton form of the zeolites obtained after removal of the organic templates was dependent on the combination of organic molecules used as SDAs. Moreover, the catalytic activity of the zeolites in m-xylene and 1-butene isomerisation increased as the relative population of strong Brönsted acid groups in sterically constrained sites inside the ferrierite cavity decreased.This work has been financially supported by the MICINN (project CTQ2006-06282).Peer reviewe

    Beyond Avelino's scientific achievements: The building process of a community in catalysis

    Get PDF
    [EN] The scientific career of Avelino has recently been reviewed in some detail [1] and the contributions included in this special issue provide additional valuable and extensive insights into several aspects of his activities from a variety of perspectives, written with the purpose of completing the picture of Avelino as the author of outstanding breakthroughs in zeolite science and catalysis. But, it is precisely his excellence in science that motivates some key questions that have never been properly addressed, not at least in printing form: how all these achievements came into being? What is the nature of the process that has made such wide range of innovations possible? How the material and human resources required for that successful process were gathered and organized? These questions are usually not of primary concern for scientific journals, as this one is, and are in general best regarded as more suitable for historically oriented publications, and even for social and philosophical aspects of the scientific research. However, we think that these questions are relevant to those scientists who are actively contributing to the fields that Avelino has explored so successfully over the years, as well as to all those who wish to understand through the study of Avelino's career how science is practiced and organized as a human activity.The authors are very grateful to Prof Vicente Fornes for providing us some invaluable information that has been included in this article. Unfortunately, Prof Fornes has refused to appear on the list of authors of this article. The authors also thank Dra. Julia Aguilar, who belonged to ITQ, for providing us with a copy of the picture included in Fig. 2. Also, the Generalitat Valenciana, Conselleria d'Innovacio, Universitats, Ciencia i Societat Digital is acknowledged for their funding via project Prometeo/2021/077.Miro, P.; Lázaro, J.; Pérez Pascual, M.; Frontela, J.; Rey Garcia, F.; Pérez Pariente, J. (2023). Beyond Avelino's scientific achievements: The building process of a community in catalysis. Microporous and Mesoporous Materials. 358. https://doi.org/10.1016/j.micromeso.2022.11240335

    Influence of Al distribution and defects concentration of ferrierite catalysts synthesized from Na-free gels in the skeletal isomerization of n-butene

    Get PDF
    The skeletal isomerization of n-butenes to isobutene has been carried out over ferrierite catalysts (Si/Al ~ 15) containing different acid sites distribution and different amount of defects. The zeolite crystals were synthesized under hydrothermal conditions in fluoride medium in the absence of alkaline cations by using suitable combinations of structure directing agents. Template-driven low density of acid sites in 10-membered-ring channels enhances the isobutene selectivity and decreases catalyst deactivation. The presence of high amount of silanol groups and Lewis acid sites increases the yields of by-products and catalysts decay.MICINN (CTQ2006-06282) CSIC (JAE-doc contract)Peer reviewe

    Gold clusters immobilized by post-synthesis methods on thiol-containing SBA-15 mesoporous materials for the aerobic oxidation of cyclohexene: influence of light and hydroperoxide

    Get PDF
    Gold nanospecies produced by a historically inspired two-liquid phase system were immobilized on plate-like mesoporous silica, SBA-15, functionalized with mercaptopropyl groups by a post-synthesis method, and the resulting materials were tested in the oxidation of cyclohexene with molecular oxygen at atmospheric pressure. The main purpose of this approach was to compare the physicochemical properties and catalytic performance of these materials with those of previously reported related materials functionalized by in situ methods during synthesis. In addition, catalytic tests under ambient lighting and darkness and also in the presence and absence of the initiator tert-butyl hydroperoxide (TBHP) were carried out. The samples were characterized by chemical analysis, N2 adsorption/desorption, TGA, SEM, HRTEM, UV-vis spectroscopy and XPS. Gold nanoclusters and isolated gold atoms but no AuNPs were found in the catalysts (0.31–2.69 wt.% of gold). The XPS shows that nearly 60% of the -SH groups (1.33 wt.% of S) were oxidized to sulphonic groups upon gold immobilization. The AuNCs and isolated gold atoms evolved in the the reaction medium to form AuNPs. The activity of the samples was lower than that of the catalysts supported on related S-bearing SBA-15 functionalized in situ, which was attributed to their different Au/S ratios, which in turn regulated the evolutionary process of the gold species during the reaction. The catalysts turned out to be inactive in darkness, which evidences that the cyclohexene oxidation carried out at ambient illumination is actually photocatalyzed by the AuNPs formed in situ during the reaction. The TBHP initiator is required to obtain the activity in order to counteract the inhibitors of cyclohexene auto-oxidation present in the commercial reagent. On the other hand, no major differences in the selectivity among the different catalysts and reactions were observed, with 2-cyclohexen-1-one and 2-cyclohexen-1-ol resulting from the allylic oxidation as main products (selectivity of (one + ol) ~80% at a conversion ≥ 35%; one/ol~2)
    corecore