Cr-free Ni/MgO catalysts for hydrogenation of furfural

In the last century, the industrial development and the increase of the world population have caused the depletion of fossil reserves. This fact together with others factors have led to the search of alternative. Biomass is emerging as a widely available source to produce energy and, excluding fossil fuels, is the only source that can provide liquid fuels and chemicals. Lignocellulose is formed by cellulose, hemicellulose, lignin and other extractable components. In the case of hemicellulose, its hydrolysis leads to the formation of xylans and pentosans, which after dehydration can give rise to furfural. The high interest for furfural is attributed to its chemical structure, which provide high reactivity, making it potentially interesting for the synthesis of a vast variety of high value-added chemicals. Two of these important chemicals are furfuryl alcohol (FOL) and 2-methylfuran (MF), can be synthesized through hydrogenation of furfural, either in liquid or vapor phase. FOL is mainly used for the production of thermostatic resins, intermediates in the manufacture of lysines, vitamin C and dispersing agents. Meanwhile, MF is used in the synthesis of pesticides, in the pharmaceutical or perfume industries. Industrially, copper chromite catalyst is used, although the toxicity associated to the presence of chromium species has prompted the search of Cr-free catalysts. Therefore, much attention is being paid to the development of more sustainable and environmentally friendly catalysts, among them, catalytic systems based on Cu or Ni have demonstrated to be active and selective towards the formation of FOL and MF. The dispersion of metalspecies and their interaction with the support are key parameters that affect the catalytic activity and stabilityof catalysts. The use of metal oxides as supports can allow to obtain highly active and stable catalytic systems, and the electronic density of metal sites can be modified. The present work is aimed at the synthesis by Ni/MgO catalysts and the evaluation of their catalytic performance in the gas phase hydrogenation of furfural, at atmospheric pressure. x-Ni_MgO catalysts have been tested in the furfural hydrogenation, attaining the full furfural conversion with the 0.20-Ni_MgO catalyst, after 5 h of TOS, at 190 °C, by feeding a 5% furfural solution in cyclopentyl methyl ether, at a constant flow of hydrogen of 10 ml min-1. In all cases, catalysts are highly selective to furan. The analysis of the influence of the reaction temperature has revealed the existence of a volcano distribution, attaining the best catalytic performance at 190 °C. However, all catalysts suffer a progressive deactivation with TOS, by deposition of reactants and product.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech Ministerio de Economía y Competitividad (Proyecto CTQ2015-64226-C3-3-R) Fondos FEDE

Supported nickel nitride catalysts for the gas-phase hydrogenation of furfural

A series of catalysts with different nickel loading (2.5-30 wt%) has been prepared by UGR. The preparation of Ni3N phase was ascertained via Powder X-rays diffraction together with cubic nickel . The elemental chemical analysis and XPS data confirm the presence of the nitride phase. Their catalytic performance points out that catalysts with loading of 5-10 wt% Ni exhibit a higher stability, maintaining furfural conversion values higher than 75% after 5 h of time-on-stream at 170ºC, and the main products detected were furfuryl alcohol (hydrogenation) and furan (decarbonylation). This would indicate that two types of active sites are present on the catalyst surface. It is noteworthy the high catalytic activity of this family of catalyst, since they exhibit a better performance than Cu-ZnO catalysts, but using a lower reaction temperature and H2/furfural molar ratio, as well as a higher furfural concentration and WHSV values. The experimental conditions have been optimized in order to achieve the maximum yield in the target product, but preserving a high activity and stability. The fresh and spent catalysts have been characterized in order to elucidate structure-activity-stability relationships.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Hydrogenation of furfural over supported Pd catalysts

Lignocellulosic biomass is the most abundant and economical non-fossil carbon source. Furthermore, it is not competitive with the food chain, coming from lignocellulosic wastes including agricultural and food processing, local urban solid and forestry wastes. However, these are made up of complex carbohydrates (mainly, cellulose and hemicellulose), which require to be broken down in their respective monomers. The hemicellulose is mainly composed of pentosans, which, after an initial hydrolysis step, are dehydrated to furfural. Furfural is an important platform molecule, since it has a wide range of applications, being considered the main chemical, aside from bioethanol, obtained from the sugar platform for the synthesis of chemicals, for plastics, agrochemical and pharmaceutical industries. In the present work, the hydrogenation of furfural in gas phase has been studied by using Pd as active phase, and different metal oxides as support, in order to elucidate the influence of the support on the catalytic performance. Furfural can be converted into chemicals with important applications in many different industrial fields. Thus, reduction of furfural can proceed through different pathways depending on the experimental conditions, where the nature of the catalysts plays a key role. In the case of Pd-based catalysts, the main products come from the decarbonylation of furfural.The catalytic results reveals that the nature of the support exerts an important influence on furfural conversion and yield. The highest conversion (92% after 5 h of TOS at 463 K) was attained with a Pd-SiO2 catalyst, with a furan yield of 70 mol%. This catalyst is the most selective to furan and a moderate deactivation is only observed after 5 h reaction. The catalytic performance demonstrates that decarbonylation reaction was the main pathway, although the formation of furfuryl alcohol and 2-methylfuran also suggests that the hydrogenation of the carbonyl group of furfural takes place.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Synthesis of type A zeolites from natural kaolinite for their application in CO2 capture processes

Climate change is the greatest environmental threat of the 21st century, with major economic, social and environmental consequences. The level of carbon dioxide (CO2) emissions has increased by 31%, therefore, both governments and the scientific community are taking steps to mitigate emissions into the atmosphere. The most economically sustainable method is the use of low cost adsorbents that perform a selective adsorption of CO2 with respect to other inert gases such as N2. Clay minerals are highly available materials on the planet, are a low cost raw material and have great versatility for various processes in the field of adsorption and catalysis. The present work describes the synthesis of type A zeolite from a hydrothermal process in basic medium using metacaolinite as a starting material. Several parameters such as temperature and time were modified to evaluate the relationship between the formation conditions of the zeolite and its CO2 adsorption capacity. Synthesized catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption at -196 ºC, nuclear magnetic resonance of solids (NMR) and infrared spectroscopy (IR). In addition, the absorption capacity of CO2 with type A zeolites has been evaluated, and all the results were compared with the commercial zeolites. With respect to the results obtained, it can be said that the bands obtained by IR for the synthesized Zeolites are similar to those of the commercial Zeolite. On the other hand, the NMR results show that the synthesized and commercial zeolite present the same chemical environment. Finally, the textural parameters corroborate that in all cases the surface area is low from 12 m2g-1 for kaolinite to 7 m2g-1 for commercial zeolite AUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Gas-Phase Hydrogenation of Furfural to Furfuryl Alcohol over Cu-ZnO-Al2O3 Catalysts Prepared from Layered Double Hydroxides

Several layered double hydroxides (LDHs) with general chemical composition (Cu,Zn)1-xAlx(OH)2(CO3)x/2 .. mH2O have been synthesized by the co-precipitation method, maintaining a (M2+/M3+) molar ratio of 3, and varying the Cu2+/Zn2+ molar ratio between 0.2 and 6.0. After calcination and reduction steps, Cu/ZnO/Al2O3 catalysts were synthesized. These catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), H2 thermoprogrammed reduction (H2-TPR), N2 adsorption-desorption at -196 ºC, N2O titration, X-ray photoelectron miscroscopy (XPS), NH3-thermoprogramed desorption (NH3-TPD) and CO2- thermoprogrammed desorption (CO2-TPD). The characterization data revealed that these catalysts are mainly meso-and macroporous, where Cu, ZnO and Al2O3 are well dispersed. The catalytic results show that these catalysts are active in the gas-phase hydrogenation of furfural, being highly selective to furfuryl alcohol (FOL) and reaching the highest FOL yield for the catalyst with a Cu2+/Zn2+ molar ratio of 1. In an additional study, the influence of the aging time on the synthesis of the LDHs was also evaluated. The catalytic data revealed that the use of shorter aging time in the formation of the LDH has a beneficial effect on the catalytic behavior, since more disordered structures with a higher amount of available Cu sites is obtained, leading to a higher yield towards FOL (71% after 5 h of time-on-stream at 210 ºC).The authors are grateful to financial support from the Spanish Ministry of Innovation, Science and Universities (Project RTI2018- 094918-B-C44) and FEDER (European Union) funds

Catalizadores de nitruro de níquel soportados en una sílice comercial para la hidrogenación selectiva de furfural en fase gaseosa

En las últimas décadas, el crecimiento del consumo mundial de energía, el agotamiento de las reservas de petróleo y las preocupaciones ambientales han incrementado el interés en el desarrollo de alternativas a los combustibles fósiles. En este sentido, los recursos de carbono no fósiles están adquiriendo un papel fundamental para la producción de energía, biocombustibles y productos químicos. La biomasa lignocelulósica es el recurso de carbono no fósil más abundante y económico, y puede no competir con la cadena alimentaria,considerándose la fuente de carbono más sostenible. Concretamente, la hemicelulosa tiene un alto potencial, ya que tras su hidrólisis y la deshidratación de la xilosa resultante se puede obtener furfural, que es una importante molécula plataforma. Actualmente, la hidrogenación de furfural permite la producción de una amplia gama de productos químicos. Los carburos y nitruros de metales de transición presentan una estructura electrónica similar a la de algunos metales nobles y, por lo tanto,se espera que posean actividades catalíticas similares a las de los metales del grupo del platino. El nitruro de níquel soportado en carbono muestra, en la hidrogenación de varias moléculas orgánicas, una conversión similar a la del níquel soportado,pero con un patrón de selectividad diferente. En nuestro caso,se ha cambiado el soporte de carbón por una sílice comercial para estudiar su comportamiento en la hidrogenación de furfural en fase gaseosa, donde los catalizadores basados en níquel exhiben un alto poder hidrogenante, pero con baja selectividad, dando lugar a diferentes productos hidrogenados. El catalizador de Ni3N-SiO2 con un 10% de Ni presenta los mejores resultados, con una conversión del 85% después de 5 h de reacción. Además, se observa que es estable con el tiempo de reacción. A 170ºC, se obtienen rendimientos en alcohol furfurílico y furano del 30 y 30%, respectivamente. Sin embargo, a mayor temperatura, el patrón de selectividad cambia.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Musical plus phonological input for young foreign language readers

Based on previous studies showing that phonological awareness is related to reading abilities and that music training improves phonological processing, the aim of the present study was to test for the efficiency of a new method for teaching to read in a foreign language. Specifically, we tested the efficacy of a phonological training program, with and without musical support that aimed at improving early reading skills in 7–8-year-old Spanish children (n = 63) learning English as a foreign language. Of interest was also to explore the impact of this training program on working memory and decoding skills. To achieve these goals we tested three groups of children before and after training: a control group, an experimental group with phonological non-musical intervention (active control), and an experimental group with musical intervention. Results clearly point to the beneficial effects of the phonological teaching approach but the further impact of the music support was not demonstrated. Moreover, while children in the music group showed low musical aptitudes before training, they nevertheless performed better than the control group. Therefore, the phonological training program with and without music support seem to have significant effects on early reading skills. [This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permission.]We would like to thank Dr. Besson, Dr. Arnold and Dr. Herrero for their suggestions. This research was funded by the Spanish Ministry of Science and Innovation [number FFI2010-15738 (subprogram FILO), Music perception and reading skills in foreign language learning project]

Learning analytics in higher education: a review of impact scientific literature

Las analíticas de aprendizaje pueden definirse como una serie de técnicas para recopilar, analizar y otorgar datos procesables y generados por parte de los estudiantes con el objetivo de elaborar estrategias adecuadas para mejorar los procesos de aprendizaje, el rendimiento de los alumnos o el de la propia institución. Este tipo de técnicas son especialmente útiles para establecer patrones de acción que guíen y orienten el proceso educativo en educación superior. Bajo estas premisas, la presente investigación tiene por objetivo analizar la producción científica de mayor impacto sobre el empleo de analíticas de aprendizaje en educación superior. Para ello se ha seguido una metodología cuantitativa atendiendo diez variables: año de publicación, publicaciones periódicas, autores, instituciones, países, tipo de documento, formato de publicación, área de publicación, idioma y artículos más citados. Los resultados proyectan una tendencia de investigación que se encuentra totalmente en auge, especialmente por la mayor producción científica ocurrida en los últimos años (2015-2018) destacando países como Australia, Estados Unidos y Reino Unido. Las publicaciones, en su gran mayoría, proceden de conferencias y se encuentran publicadas en inglés. Destacan las áreas de conocimiento de Ciencias Computacionales y Ciencias Sociales.Learning analytics can be defined as a series of techniques for collecting, analyzing and granting processable data generated by students. Their objective is to develop appropriate strategies to improve the learning processes, the performance of the students or that of the institution itself. These types of techniques are especially useful to establish patterns of action that guide and guide the educational process in higher education. Under these premises, the present research aims to analyze the scientific production with the greatest impact on the use of learning analytics in higher education. For this purpose, a quantitative methodology has been followed, based on ten variables: year of publication, periodicals, authors, institutions, countries, type of document, publication format, publication area, language and most cited articles. The results project a research trend that is fully on the rise, especially due to the greater scientific production that has occurred in recent years (2015- 2018), highlighting countries such as Australia, the United States and the United Kingdom. The publications, in their great majority, come from conferences and are published in English. The knowledge areas of Computational Sciences and Social Sciences stand out.Ministry of Education, Culture and Sport through the Aid of the University Teaching Staff Training Program FPU14/0462

Furfuryl alcohol production by liquid phase catalytic transfer hydrogenation of furfural on alumina as Lewis acid catalyst

Currently, much attention is being paid to the development of efficient and environmentally friendly technologies for the sustainable production of energy, fuels and chemicals [1]. In this context, lignocellulosic biomass appears as a renewable alternative feedstock to fossil resources. Thus, dehydration of C5 carbohydrates leads to furfural (FUR), a versatile platform molecule for the synthesis of a large spectrum of chemicals. Among them, the most important is furfuryl alcohol (FOL), accounting for 65% of FUR production, which finds application in the preparation of resins used as high-quality cores and molds for metal casting, reactive solvent for phenolic resins in the refractory industry, chemical building block for the synthesis of tetrahydrofurfuryl alcohol and pharmaceuticals and manufacture of fragrances [2,3]. FOL is prepared industrially by the catalytic hydrogenation of furfural, which can be carried out in vapor or liquid-phases, being the former in the presence of copper chromite the preferred industrial route. However, other products such as 2-methylfuran, tetrahydrofurfuryl alcohol and 2-methyl tetrahydrofuran can result from furfural hydrogenation, besides furan and THF, different pentanediols, 2-pentanone and 2-pentanol, cyclopentanone and cyclopentanol. The selectivity pattern depends strongly on reaction conditions and on the nature of the catalyst used. Nevertheless, a synthetic approach based on the catalytic transfer hydrogenation (CTH), based on the Meerwein-Ponndorf-Verley (MPV) reduction of an aldehyde (or ketone) coupled to the oxidation of a secondary alcohol, has been also proposed, which does not require supply of external hydrogen and the alcohol can be chosen in order to produce an aldehyde or ketone with industrial applications [4,5]. The present contribution deals with the production of FOL from furfural by CTH, using different commercial aluminas as catalysts and a secondary alcohol as hydrogen donor, in liquid phase. The results have demonstrated that the formation of other by-products is minimized and FOL is produced in high yield, at temperatures ranging between 90 and 150ºC, by using 2-propanol. Thus, full conversion of furfural and a FOL selectivity higher than 90 mol% are attained after only 2 h, at 150ºC, a FUR concentration of 0.25 M in 2-propanol and a catalyst/FUR weight ratio of 1:1 (Fig. 1). A reaction mechanism, involving Lewis acid sites present on the alumina surface in the activation of FUR and 2-propanol, has been put forward. Different experimental parameters (FUR concentration, reaction temperature, catalyst loading, type of alumina and nature of alcohol) have been optimized in order to achieve suitable FOL yields. Moreover, reutilization has been evaluated to support the advantage of the heterogeneous catalytic process which allows the reuse of the solid catalyst. Finally, and considering that dehydration of xylose to furfural is accomplished in the presence of solid acid catalysts, the one-pot synthesis of FOL from xylose has been undertaken by tuning selected experimental variables.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Catalizadores de cobre soportados en kerolita para la hidrogenación del furfural en fase gas

La biomasa está adquiriendo un papel fundamental para la producción de energía, biocombustibles y productos químicos. La hemicelulosa tiene un alto potencial ya que su hidrólisis y deshidratación de la xilosa resultante pueden dar lugar a furfural. Actualmente, su hidrogenación a alcohol furfurílico consume la mayor parte del furfural producido; este proceso catalítico se lleva a cabo usando catalizadores basados en cromita de cobre, pero la toxicidad del cromo ha impulsado el desarrollo de nuevos sistemas catalíticos más sostenibles y respetuosos con el medio ambiente. Cabe mencionar que también existe la posibilidad de obtener otros productos interesantes como son el 2-metilfurano (MF), el furano o incluso, se puede llegar a la apertura del anillo furánico. En bibliografía se han propuesto catalizadores metálicos sin cromo, a base de Cu o Ni, activos y selectivos hacia los productos de reacción antes mencionados, en función de las condiciones experimentales y del binomio fase activa - soporte. En el presente trabajo se ha sintetizado por el método de coprecipitación-deposición una familia de catalizadores metálicos de Cu soportado en kerolita, un mineral de la familia de las arcillas, los cuales se han denotado como K-xCu (donde x es el porcentaje de Cu = 5-30%), que se sometieron a calcinación y reducción para obtener los diferentes catalizadores metálicos. Además, se ha evaluado la influencia de la adición de promotores (CeO2 y ZnO) en la etapa de síntesis, sobre el comportamiento catalítico con el fin de obtener catalizadores estables y selectivos. La influencia del contenido en cobre en la catálisis juega un papel importante ya que los valores de conversión de furfural aumentan con el contenido en cobre, alcanzando un 90% para el K-15Cu tras 5 h de reacción. El alcohol furfurílico y el 2-metilfurano han sido los únicos productos detectados, favoreciéndose la formación de alcohol furfurílico con la adición de promotores.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec