γ-Al2O3 as acid catalyst for dehydration of glucose to 5-hydroxymethylfurfural

Currently, the search and development of sustainable feedstocks for chemicals derived from petrol have gained worldwide attraction because of the instability of the price of crude oil, the reduction of fossil oil reserves, and the environmental concerns associated to the greenhouse effect caused by CO2 emissions, being biomass one of the world’s most important renewable carbon sources. The major component of plant-derived biomass are carbohydrates, being of great importance to develop efficient and green approaches to their valorization by conversion into high value-added products. Thus, glucose can be transformed by dehydration into 5-hydroxymethylfurfural (HMF), which is a versatile and key intermediate for the production of a wide variety of biobased chemicals and it is attracting much attention in biofuels and chemical industry. Different catalytic systems have been evaluated for HMF production from C6 carbohydrates as glucose, mostly based on heterogeneous catalysis as alternative to the use of liquid mineral acids. On the other hand, the high surface area, large pore size and thermal and hydrothermal stabilities of some mesoporous solids make them suitable for many catalytic processes. In the present work, the dehydration of glucose to HMF has been evaluated by using different mesoporous γ-Al2O3 with acid, neutral or basic character, in a biphasic water–MIBK solvent system to avoid the HMF degradation and its possible reaction with the intermediates from glucose to give soluble polymers and humins or acetalization with glucose. Different experimental parameters, such as reaction temperature and time, as well as the addition of inorganic salts have been studied in order to reach the maximum HMF yield.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Ministry of Economy and Competitiveness (CTQ2012-38204-C04-02 project), Junta de Andalucía (RNM-1565) and FEDER fund

Efecto sinérgico entre sales inorgánicas y γ-Al2O3 para la deshidratación de xilosa a furfural

La biomasa lignocelulósica, con un alto contenido en hemicelulosa, es una de las principales fuentes de pentosas pentosas a partir de las cuales se pueden obtener biocombustibles y productos químicos de alto valor añadido, como el 2-Furfuraldehído (furfural), producido por deshidratación de xilosa mediante catálisis ácida. Se han estudiado diferentes catalizadores sólidos ácidos como alternativa a los ácidos minerales convencionales. Además, el uso de sales inorgánicas para mejorar el rendimiento a furfural, sobre todo en sistemas bifásicos, ha sido previamente recogido en la bibliografía. En este trabajo, se ha estudiado la deshidratación de xilosa a furfural empleando sistemas bifásicos agua:tolueno en presencia de γ-Al2O3 mesoporosa, y se ha evaluado el efecto de la adición de CaCl2 o MgCl2 al medio de reacción sobre el rendimiento en furfural. La γ-Al2O3 es muy activa en la deshidratación de xilosa a furfural a 175ºC, pero los rendimientos no son altos debido a reacciones secundarias (Figura 1). Sin embargo, se ha demostrado previamente que sales alcalinotérreas como el CaCl2 interaccionan con moléculas de glucosa en el medio de reacción, acelerando considerablemente su deshidratación, por lo que sería posible que también influyesen en la deshidratación de xilosa. Por ello, se ha estudiado el efecto del CaCl₂ y MgCl₂, adicionando el mismo número de moles, siendo 0.65 y 0.39 g sal·g.dis.acuosa, respectivamente. Se observa un considerable aumento, tanto de la conversión de xilosa como del rendimiento en furfural al añadir estas sales, siendo máximos (96% y 71%, respectivamente) en el caso del CaCl2, superiores a los alcanzados en presencia de γ-Al2O3.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Production of Biofuels by 5-Hydroxymethylfurfural Etherification Using Ion-Exchange Resins as Solid Acid Catalysts

In this work, acidic ion-exchange resins with strong Brönsted sulphonic groups were assessed in the catalytic etherification of the platform molecule 5-(hydroxymethyl)furfural (HMF) to 5-(ethoxymethyl)furfural (EMF), a biofuel with an energy density close to that of gasoline (30 MJ/L) which also reduces emissions of NOx and SOx and solid particles respect to fossil-derived fuels. Catalytic performance was optimized modifying experimental parameters such as reaction time, temperature, and concentration of reagent employed. This process was carried out in batch reactors using ethanol 96% as solvent. Among different cation-exchange resins tested, Purolite CT275DR provided the fastest HMF conversion together with Purolite PD206, and the highest selectivity to EMF, achieving above 70% selectivity at 100 °C. Over time, strong acid sites favoured product hydrolysis opening the furan ring originating ethyl levulinate (EL) to the detriment of EMF selectivity. Purolite CT275DR was also utilised to realize the transformation from sugars directly to EMF in the same reaction medium, in a one-pot process, obtaining relevant results from fructose (37% HMF yield, 21% EMF yield after 5 h), but originating selectively ethylglucosides and ethylgalactosides in the presence of glucose and galactose, respectively, due to the absence of necessary Lewis acid sites to isomerize aldose and proceed with dehydration.Spanish Ministry of Economy and Competitiveness (RTI2018-94918-B-C44), FEDER (European Union) funds (UMA18-FEDERJA-171) and Malaga Universit

Recovery of pentoses-containing olive stones for their conversion into furfural in the presence of solid acid catalysts

Olive stones were employed as feedstock for furfural production in two stages: 1) autohydrolysis of hemicellulosic fraction to recover their pentoses, mainly xylose, and 2) subsequent dehydration of pentoses into furfural. Autohydrolysis step was optimized by using different experimental conditions (temperature: 160-200 ºC and time: 30-75 min), giving rise to liquors with different xylose concentrations, since hydrolysis was incomplete in some cases. The combined use of a commercial γ-Al2O3 and CaCl2 led to total hydrolysis of non-hydrolyzed pentosans after autohydrolysis step, and the subsequent dehydration of pentoses into furfural. The maximum values of furfural yield and efficiency were 23 and 96%, respectively, after only 60 minutes at 150 ºC by using liquor obtained by autohydrolysis at 180 ºC and 30 min (L5.1) as source of pentoses. This liquor, L5.1, provided better catalytic results than other liquors which had shown higher xylose concentration after autohydrolysis, probably due to these latter also exhibited a higher concentration of organic acids; thus, the presence of organic acids such as acetic and lactic acid could promote side undesired reactions leading to lower furfural yields. Finally, γ-Al2O3 was more effective for furfural production under these experimental conditions than other solid acid catalysts, such as mesoporous Nb2O5, Nb-doped SBA-15 and Zr-doped HMS silicas, probably due to alumina has a higher density of acid sites.Spanish Ministry of Economy and Competitiveness (RTI2018-94918-B-C44 project), Junta de Andalucía (RNM-1565), FEDER (European Union) funds (UMA18-FEDERJA-171) and Malaga University. C.G.S. and J.A.C. thank to FEDER funds and Malaga University respectively for financial support. L.S.C. gratefully acknowledges support from Spanish MINECO via the concession of a Ramon y Cajal contract (RYC-2015-17109)

Influence of Lewis and Brønsted acid catalysts in the transformation of hexoses into 5-ethoxymethylfurfural

Several sulfonated polymers, which are typical Brønsted acid catalysts, have been employed in the production of two biofuels: 5-ethoxymethylfurfural (EMF) and ethyl levulinate (EL) as main byproduct, and the catalytic results have been attributed to their different chemical and morphological properties. The Purolite CT275DR attained the best results from 5-hydroxymethylfurfural (HMF) with a 63% EMF yield after 16 h at 100 ◦C thanks to their more abundant superficial acid sites. Moreover, Purolite CT275DR was able to efficiently dehydrate and etherify fructose, with a total EMF plus EL yield of 65% after 24 h at 100 ◦C. When glucose or galactose were used as feedstock, alumina was utilized to provide Lewis acid sites, necessary for the transformation of aldoses in so- lution enabling a combined biofuel yield (EMF plus EL) of 40% from glucose after 24 h at 140 ◦C. With the study of the role of each catalyst, both Brønsted and Lewis acid catalysts (resin and alumina, respectively) were required to obtain considerable EMF yields from aldoses. The reutilization of the catalysts employed for 5 cat- alytic runs demonstrated that Purolite CT275DR suffers no appreciable loss of activity, but alumina showed progressive losses in activity in each cycle due to carbonaceous deposits and catalyst loss.Funding for open access charge: Universidad de Málaga / CBUA This research was funded by the Spanish Ministry of Innovation, Science and Universities (RTI2018-094918-B-C44), FEDER (European Union) funds (RTI2018-094918-B-C44 and UMA18-FEDERJA-171) and Malaga University. Authors thank to Universidad de M ́alaga/CBUA for funding for open access charge. C.G.S. acknowledges FEDER funds for her postdoctoral contract (UMA18-FEDERJA-171). B.T.O. acknowledges the Ministerio de Universidades for his predoctoral contract (FPU20/ 02334

Valorización de huesos de aceituna como residuos agroalimentarios de naturaleza lignocelulósica mediante el uso combinado de Gamma-Al2O3 y CaCl2

Finalmente, se comparó la alúmina ácida con otros catalizadores ácidos sólidos, tales como Nb2O5 mesoporoso,sílice SBA-15 dopada con Nb ysílice HMS dopada con Zr, y se pudo comprobar que la gamma-Al2O3 es el catalizador más efectivo de todos para la deshidratación de azúcares, ya que presenta una mayor densidad de sitios ácidos. Además, se pudo reutilizar durante varios ciclos catalíticos en todos los casos.El agotamiento de los recursos fósiles debido a su cada vez mayor demanda e impacto medioambiental generado en la sociedad actual, ha derivado en la búsqueda de alternativas más sostenibles, como las energías y recursos renovables, dentro de los cuales, la biomasa se presenta como una materia prima de enorme potencial, debido principalmente a su carácter renovable, amplia distribución geográfica y alto contenido en carbono. Por ello, la biomasa lignocelulósica se utiliza como materia prima, para la obtención de compuestos químicos de alto valor añadido. La presente Tesis Doctoral se centra en la obtención de diferentes productos químicos de alto valor añadido, como HMF y furfural, mediante catálisis heterogénea, a partir de azúcares C6 y C5 (glucosa y xilosa, respectivamente), utilizando para ello un catalizador sólido mesoporoso como es gamma-Al2O3, que se ha caracterizado mediante distintas técnicas de análisis como XRD, adsorción-desorción de N2 a -196 °C, XPS y NH3-TPD. Posteriormente, se realizaron diferentes estudios catalíticos utilizando gamma-Al2O3 ácida junto con CaCl2 como sal inorgánica añadida al medio de reacción, consiguiendo un efecto sinérgico entre ambos. Además, se ha obtenido furfural partiendo de biomasa natural como materia prima, concretamente huesos de aceituna, ricos en hemicelulosa mediante la deshidratación de los azúcares C5 contenidos en ellos, principalmente xilosa. Para ello se fabricaron licores derivados de la fracción hemicelulósica en dos etapas utilizando diferentes condiciones de operación (160-200 °C de temperatura y 30-75 minutos de tiempo de reacción), dando lugar así a licores hemicelulósicos con diferentes concentraciones de xilosa. A esta etapa le siguió otra donde se realizó la deshidratación de los carbohidratos C5 presentes en estos licores para la obtención de furfural, mediante el uso combinado de gamma-Al2O3 y CaCl2

Valorization of olive stones to obtain furfural in the presence of gamma-Al2O3 and CaCl2

Furfural is considered as one of the 12 platform molecules derived from biomass for the synthesis of high value-added chemicals. It is mainly produced by acid-catalyzed dehydration ofpentoses, such as xylose, which can be obtained from hemicellulose, one of the main components of lignocellulosic biomass. The aim of this work was to obtain furfural from lignocellulosic wastes from the agro-food industry, such as olive stones. For this purpose, the catalytic behavior of a mesoporous g-Al2O3 as acid solid catalyst and the effect of the addition of CaCl2 in order to improve the furfural yield were evaluated. Firstly, the production of sugar-rich liquors from olive stones was optimized in a thermostated 2 L reactor under continuous stirring, by using water as solvent with a solid:liquid mass ratio of 1:10, at 160-200 °C for 30-75 minutes. The liquors H7 and H10 obtained at 180 °C and 60 minutes and 190 °C and 45 minutes, respectively, showed the highest xylose contents and they were chosen for furfural production. The catalytic dehydration of pentoses-containing liquors, mainly D-xylose, was studied in batch type glass reactors in a thermostated aluminum block under magnetic stirring, at 150 °C for 50 minutes. In a typical test, 1.5 mL of liquor, 3.5 mL of toluene, 50 mg of g-Al2O3 and 0.65 g CaCl2·g.sol -1 were added to the reaction medium. The reaction products were analyzed by HPLC. The presence of the catalyst, g- Al2O3, hardly improves the performance of furfural with respect to the non-catalytic process . However, an increase in furfural yield is observed in the presence of CaCl2, being maximum when g-Al2O3 and CaCl2 are used together (100% and 74% for H7 and H10, respectively). The lower yield attained from H10 could be due to the use of a higher temperature to obtain this liquor, since the formation of degradation products, such as formic acid, acetic acid and HMF, could promote secondary reactions of furfural, consequently decreasing the furfural yield.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Synergic effect between inorganic salts and gamma-Al2O3 for xylose dehydration to furfural

Lignocellulosic biomass, with a high content of hemicellulose, is the main source of pentoses, from which biofuels and value-added chemicals can be produced. Amongst the latter, 2-Furfuraldehyde (furfural, FUR) is the only unsaturated organic compound prepared from carbohydrates, obtained by acid-catalyzed dehydration of xylose (XYL). Different acid solid catalysts have been studied as alternative to conventional mineral acids, which are employed in industry. In this work, the dehydration of XYL in a biphasic water:toluene system with a mesoporous γ-Al2O3 has been studied, and the effect of the presence of CaCl2 or MgCl2 in the reaction medium on the catalytic performance was evaluated. The presence of CaCl2 and the use of γ-Al2O3 in the reaction medium for xylose dehydration to furfural were studied and compared to the non-catalytic process, at 175 °C. In all cases, high conversion values were attained with respect to the non-catalytic process. γ-Al2O3 shows a high activity, with a XYL conversion of 96%, after 90 min of reaction, but the furfural yield was lower than expected due to alumina favored secondary reactions. Thus, high furfural yields were achieved by using CaCl2 even in absence of catalyst under these experimental conditions. However, considering that side reactions are favored at high temperatures, the catalytic process was studied with CaCl2 and γ-Al2O3 at 150 °C. At this lower temperature, a synergistic effect can be inferred between γ-Al2O3 and CaCl2, reaching values of XYL conversion and FUR yield of 99% and 59%, respectively, after only 30 min of reaction. Moreover, the effect of the addition of CaCl2 and MgCl₂ was compared (Fig. 3), adding the same number of moles, corresponding to 0.65 and 0.39 gsalt·gaq.sol., respectively. Although both salts improved the catalytic performance, CaCl2 is more beneficial than MgCl2. The reaction mechanism has been studied by 1H NMR.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Valorización de huesos de aceituna para la obtención de furfural en presencia de gamma- Al2O3 y CaCl2

En la actualidad, se considera que la biomasa lignocelulósica es una materia prima sostenible muy prometedora, ya que es la única fuente de carbono renovable que no compite con la cadena alimentaria. A partir de ella puede obtenerse energía, así como combustibles y productos químicos de alto valor añadido como el furfural, el cual ha sido identificado por el Departamento de Energía de los Estados Unidos (DOE) como una de las 12 moléculas plataforma con mayor relevancia. Así, el furfural es un precursor muy versátil para sintetizar una gran variedad de productos químicos, como el alcohol furfurílico o el ácido furoico, entre otros productos de interés. Actualmente, el furfural se produce principalmente mediante hidrólisis ácida de la hemicelulosa, uno de los principales componentes de la biomasa lignocelulósica, formada mayoritariamente por unidades de pentosas como la xilosa, cuya posterior deshidratación en presencia de un catalizador ácido conduce a furfural. En el presente trabajo se pretende la obtención de furfural a partir de licores ricos en carbohidratos procedentes de residuos lignocelulósicos, más concretamente, de huesos de aceituna. Con este fin se ha evaluado el comportamiento catalítico de una gamma-Al2O3 mesoporosa como catalizador sólido ácido, como alternativa al uso de ácidos minerales convencionales, y además, también se ha estudiado el efecto de la adición de sales inorgánicas como el CaCl2 para mejorar el rendimiento a furfural. La presencia de gamma-Al2O3 y CaCl2 permite obtener un rendimiento en furfural del 100% usando licores procedentes de los huesos de aceituna como fuente de xilosa, obtenidos tras hidrólisis a 180 ºC y 60 min.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Trabajar el arte en Educación Infantil

Se presenta memoria final de proyecto educativo que pretende demostrar que desde muy pequeños los niños y niñas de Educación Infantil pueden observar obras de arte de autores consagrados y expresar los sentimientos que esta interacción despierta en ellos y ellas. Se realiza en el CEIP Eduardo Ocón Rivas de Benamocarra, Málaga. Los objetivos son: acercar la pintura a la comunidad escolar; observar e interpretar lo observado; razonar la contemplación de el arte; aprender a escuchar los sentimientos que despierta una obra; despertar en el alumnado un interés personal por el lenguaje plástico; disfrutar y criticar con criterio; conocer a célebres pintores e investigar su vida y su obra; ampliar la biblioteca de aula; trabajar el lenguaje escrito partiendo del lenguaje plástico y viceversa. Los resultados demuestran que los niños y niñas de infantil poseen la capacidad suficiente para tratar el arte con mayúsculas, y de 'tu a tu'; queda comprobada la multitud de posibilidades que nos ofrece la pintura para ilustrar cualquier aspecto de los contenidos de educación infantil.Junta de Andalucía. Consejería de EducaciónAndalucíaES