Producing nanosized zeolites Y has been restricted to a Si/Al ratio lower than 2.0, requiring prolonged crystallization periods. This study employed temperature ramps during nucleation and crystallization to synthesize nanosized zeolites Y with a Si/Al ratio of 2.4, ranging from 47 to 100 nm, in just one day. Sequential post-synthesis desilication and dealumination treatments were used to modify the pore structure and acidity of the zeolites, leading to hierarchical zeolite formation. These modifications enhanced the structural stability and porosity of the zeolites while preserving their high crystallinity. Desilicated zeolites, unlike dealuminated ones, possessed straighter and more uniform mesoporous within their crystals, with diameters smaller than 5 nm. Additionally, successive desilication produced a greater number of intracrystalline mesoporous. The solids obtained from both processes exhibited porosity within the zeolite structure connected to the external surface, potentially improving the mass transfer limitations of the original zeolite due to the lack of mesoporous. Catalysts were prepared using modified nanozeolites for evaluation in the propylene oligomerization reaction. Catalysts based on dealuminated and desilicated nanosized zeolite Y showed high conversions above 20

The synthesis of submicrometric Y zeolites has only been achieved for a Si/Al ratio lower than 2.0 for long crystallization times. In this work, submicrometric Y zeolites in the range of 100-200 nm were synthesized with a Si/Al ratio equal to 2.4 in just 24 h. Post-synthesis methods allow tuning the porosity and the acidity of the microporous Y zeolites leading to hierarchical zeolites. Hierarchical Y zeolites were obtained by post-synthetic modification of submicrosized Y zeolites, synthesized under organic template-free conditions. The influence of the post-synthetic modification on the structure, particle size, morphology, surface area and acidic properties of the zeolites was studied. The post-synthetic modification involved either sequential desilication-dealumination (DES-DEA) or sequential dealumination-desilication (DEA-DES) of the zeolite framework involving both leaching with NaOH and steaming processes. Structurally more stable zeolites with hierarchical porosity and high crystallinity were synthesized by the sequential DES-DEA process proposed in this work. Sequential DES-DEA process allowed two relevant results in applications of these zeolites for catalysis. On one hand, it allowed a more ordered and controlled dealumination which led to retaining the number of Bronsted acid sites when the NaOH concentration was changed. Characterization of surface acidity revealed protection of the structural aluminum due to the first step of desilication before the dealumination. On the other hand, this method produced simultaneously both intraparticle and interparticle mesoporosity. With the obtained zeolites, NiMo catalysts were prepared and evaluated in the vacuum gas oil hydrocracking reaction. The catalysts based on zeolites obtained by DES-DEA were more active at lower temperatures and exhibited higher yields of middle distillates compared to those obtained with zeolites synthesized by the DEA-DES method. The desilication-dealumination process allowed the production of structurally more stable submicrometric Y zeolites with hierarchical porosity and high crystallinity.

The merits of Chemical Engineering as an industrial activity are in fact unknown to a significant fraction of the population.Chemical engineers work in almost every industry and affect the production of most large-scale manufactured items.Developing products more and more efficiently through chemical processes involves the design of reactors and the use of catalysts.More than 90% of the products are obtained from catalytic processes or the presence of a catalyst is involved in some step of their manufacturing process.As expected, catalysis has spread to other industries, such as health and foods, thus entering unconventional environments, which involve new ways of preparing catalysts and reactors, capable of offering a wide spectrum of reaction conditions and the admission of different raw materials.Although catalysis has been around for more than two centuries, it constitutes one of the fields of applied science with the greatest validity today, representing one of the areas in which research is ever growing.Some of the reasons behind this are the innumerable applications of catalysis in different industries and the effects it generates on the costs of each production process.On the other hand, the rising interest in mitigating environmental damage has also led researchers and professionals to consider environmentally-friendly processes, to obtain new products from renewable and non-renewable sources, which increases the challenges associated with the development of new technologies.In our School of Chemical Engineering, belonging to the Faculty of Engineering in The University of Zulia, we count on professors with widely recognized academic careers, lengthy experience, capabilities and willingness to train engineers with the necessary knowledge to face the challenges demanded by modern industry.Fortunately, we have a great expression of what a professional in Chemical Engineering should be, an outstanding teacher and a tireless researcher in catalysis, respected and appreciated by all, we refer to Prof. Jorge Sánchez.Although this journal presents researches in different branches of Engineering, I allow myself through these lines genuinely call forth some of his memories, as it is difficult not to mention a professional scholar, acknowledged for his vocation and values, for inspiring and fostering in his students, technical and ethical principles, as well as essential attitudes imperative in any engineer.From a very young age, Prof. Jorge Sánchez found his calling for teaching, he even commented on several occasions that in his high school days, his classmates called him: "Salvation", due to his great willingness to explain different topics.Later, in our college years, we were able to witness this, as he was a teaching assistant for various subjects, and when he graduated, he did not hesitate to enter his beloved Alma Mater."I had no doubt about wanting to enter the University of Zulia as a professor, nor did I think about it.",he professed.

The present work reports the synthesis of beta zeolite and its modification with phosphorous in different percentages of P2O5 (1 and 5%) and vacuum gas oil (VGO) hydrocracking (HCK) conversion and yield to naphtha and middle distillates. The solids were characterized by X-ray diffraction, elemental analysis by atomic absorption spectroscopy and inductively coupled plasma atomic emission spectrometry (ICP-AES), N-2 adsorption, Al-27 magic angle spinning-nuclear magnetic resonance ( Al-27-MAS-NMR), temperature-programmed desorption of ammonia (NH3 -TPD) and isopropylamine (IPam-TPD), pyridine adsorption followed by Fourier transform infrared spectroscopy (Py-FTIR), hydrogen temperature programmed reduction, transmission electron microscopy, and energy-dispersive X-ray (TEM-EDX). The catalysts were tested in a tubular reaction system at 350 degrees C, 10 342 kPa, H-2/feed: 1250 NL/L, LHSV: 1 h(-1)with prehydrotreated VGO. Overall activity and middle distillates and naphtha yields were influenced by the phosphorous impregnation on beta zeolite. Between 4 and 6% higher conversion was observed. Textural and acid properties were modified by the phosphorous treatment leading to a total acidity and surface area decrease with phosphorous content. Relative changes in tetrahedral and extra-framework aluminum were followed by Al-27-MAS-NMR. Al-((4)) assigned to distorted extra-lattice tetrahedral aluminum and Al-O(2) extra framework aluminum increased with phosphorous impregnation. Strong acidity monitored by IR of adsorbed pyridine showed a direct correlation with VGO conversion and naphtha yields.

Las propiedades catalíticas de materiales compuestos de arcilla-sílice mesoporosa modificada con cobalto fueron evaluadas para la deshidrogenación catalítica de etilbenceno a estireno. Los materiales fueron preparados incorporando diferentes contenidos de óxido de cobalto mediante dos métodos: por incorporación directa dentro del gel de síntesis y por impregnación a humedad incipiente. La caracterización de los sólidos se realizó mediante fluorescencia de rayos X, adsorción física de nitrógeno, reducción a temperatura programa y difracción de rayos X. Los materiales preparados presentaronmejores propiedades texturales que la arcilla de partida, además, mostraron una forma de isoterma de adsorción del tipo IV con lazo de histéresis tipo H3. En los sólidos impregnados las especies de cobalto se redujeron a una temperatura inferior a la observada para los materiales obtenidos por incorporación del cobalto en el gel de síntesis. Se evidenció la formación de la fase Co3O4 en los materiales con un contenido metálico mayor. La conversión de etilbenceno mejoró con el incremento del contenido de cobalto en ambas series de materiales, sin embargo, la conversión disminuyó para el material impregnado de mayor carga, causado posiblemente por sinterización. La selectividad decreció al aumentar la temperatura y el tiempo de residencia en los ensayos realizados en los catalizadores más activos para cada método de preparación.

Las propiedades catalíticas de materiales compuestos de arcilla-sílice mesoporosa modificada con cobalto fueron evaluadas para la deshidrogenación catalítica de etilbenceno a estireno. Los materiales fueron preparados incorporando diferentes contenidos de óxido de cobalto mediante dos métodos: por incorporación directa dentro del gel de síntesis y por impregnación a humedad incipiente. La caracterización de los sólidos se realizó mediante fluorescencia de rayos X, adsorción física de nitrógeno, reducción a temperatura programa y difracción de rayos X. Los materiales preparados presentaron mejores propiedades texturales que la arcilla de partida, además, mostraron una forma de isoterma de adsorción del tipo IV con lazo de histéresis tipo H3. En los sólidos impregnados las especies de cobalto se redujeron a una temperatura inferior a la observada para los materiales obtenidos por incorporación del cobalto en el gel de síntesis. Se evidenció la formación de la fase Co3O4 en los materiales con un contenido metálico mayor. La conversión de etilbenceno mejoró con el incremento del contenido de cobalto en ambas series de materiales, sin embargo, la conversión disminuyó para el material impregnado de mayor carga, causado posiblemente por sinterización. La selectividad decreció al aumentar la temperatura y el tiempo de residencia en los ensayos realizados en los catalizadores más activos para cada método de preparación.

We focus on the selective hydrogenation using NiPd/(xCeO2-)Al2O3catalysts under liquid and gas conditions.

Resumen Se prepararon compuestos de arcilla-silice mesoporosa mediante la ruta de los complejo satrano. Estos solidos fueron modificados con oxido de hierro a traves de dos vias: en sintesis con relaciones molares Si/Fe de5, 10, 20 y 40, e impregnacion a humedad incipiente con cargas de oxido de hierro de 5, 7, 9 y 12 %. Los materiales preparados fueron caracterizados por fisisorcion de nitrogeno, difraccion de rayos X, desorcion de amoniaco a temperatura programada y reduccion a temperatura programada. Se evaluo la actividad catalitica de dichos materiales para la reaccion de deshidrogenacion catalitica de etilbenceno a estireno. Los materiales obtenidos mostraron mejores propiedades texturales que el material de partida, destacando la formacion de mesoporos de aproximadamente 3nm con una distribucion estrecha de tamanos de poro. Se obtuvieron mejores propiedades texturales para la serie preparada en impregnacion. Los ensayos de TPR mostraron que el hierro fue incorporado en el entramado de silice en diferentes formas. En general, se observaron bajas conversiones y altas selectividades. La baja actividad fue atribuida a la rapida desactivacion de las especies de hierro mediante la formacion de coque. Resultados afirmaron que el metodo de incorporacion de hierro ejercio influencia en su desempeno catalitico. Palabras claves: deshidrogenacion, estireno,etilbenceno, materiales mesoporosos, oxido de hierro. Abstract Clay-mesoporoussilica composites were prepared by the atrane complexes route. These solids were modified with iron oxide through two routes: in synthesis with Si/Fe molar ratios of 5, 10, 20 and 40, and incipient wet impregnation with iron oxide loads of 3, 5, 7, 9 and 12 %. The prepared materials were characterized by nitrogen physisorption, X-ray diffraction, ammonium desorption at programmed temperature and reduction at programmed temperature. The catalytic activity of these materials was evaluated for the catalytic dehydrogenation reaction of ethylbenzene to styrene. The obtained materials showed better textural properties than the starting material, emphasizing the formation of mesopores of approximately 3nm with a narrow distribution of pore sizes. Better textural properties were obtained for solids prepared by impregnation. The TPR tests showed that iron was incorporated into the silica framework in different forms. In general, low conversions and high selectivity were observed. The low activity was attributed to the rapid deactivation of iron species by the formation of coke. Results affirmed that the incorporation methods of iron influenced its catalytic performance. Keywords: dehydrogenation, ethylbenzene, iron oxide, mesoporous material, styrene.

Clay-mesoporoussilica composites were prepared by the atrane complexes route. These solids were modified with iron oxide through two routes: in synthesis with Si/Fe molar ratios of 5, 10, 20 and 40, and incipient wet impregnation with iron oxide loads of 3, 5, 7, 9 and 12 %. The prepared materials were characterized by nitrogen physisorption, X-ray diffraction, ammonium desorption at programmed temperature and reduction at programmed temperature. The catalytic activity of these materials was evaluated for the catalytic dehydrogenation reaction of ethylbenzene to styrene. The obtained materials showed better textural properties than the starting material, emphasizing the formation of mesopores of approximately 3nm with a narrow distribution of pore sizes. Better textural properties were obtained for solids prepared by impregnation. The TPR tests showed that iron was incorporated into the silica framework in different forms. In general, low conversions and high selectivity were observed. The low activity was attributed to the rapid deactivation of iron species by the formation of coke. Results affirmed that the incorporation methods of iron influenced its catalytic performance.

Se prepararon catalizadores de Pd soportados sobre Al2 O3 , CeO2 /La2 O3 -Al2 O3 , Ce0,73Tb0,27Oδ-x/La2 O3 -Al2 O3 y Ce0,6Zr0,4Ox / La2 O3 -Al2 O3 , utilizando la tecnica de impregnacion a humedad incipiente. Los catalizadores fueron caracterizados mediante las tecnicas de Fluorescencia de Rayos X (FRX), Difraccion de Rayos X (DRX), Reduccion a Temperatura Programada (RTP), Quimisorcion de CO y Capacidad de Almacenamiento de Oxigeno (CAO). La actividad catalitica se estudio mediante la reaccion de reduccion de NO por CO en condiciones de alimentacion estequiometricas. Los patrones de DRX mostraron que la cristalinidad de las muestras no es afectada por los tratamientos termicos. Los resultados de RTP indicaron que la adicion de Tb o Zr promovio la reducibilidad del oxido de cerio a mas baja temperatura y la formacion de la fase β-PdHx despues de dos ciclos de reaccion, asi como un incremento en la CAO. La actividad catalitica mejoro luego de dos ciclos de reaccion, siendo el catalizador mas activo el de 0,5%Pd/Ce0,6Zr0,4Ox /La2 O3 -Al2 O3 . Este resultado sugiere cambios en la especies de PdO que junto con el oxido mixto CeZr, generan especies de mayor actividad

The catalytic performance of Al2O3-supported monometallic and bimetallic catalysts in selective hydrogenation of 1,3-butadiene in the presence of 1-butene under liquid phase conditions was studied. Bimetallic catalysts were prepared by the coimpregnation method with the required amounts of the precursors salts [Ni(NO3)2·6H2O and Pd(NH3)4Cl2·H2O] over pellet-form γ-Al2O3 with a constant content of Pd (0.5 wt%) and varying Ni/Pd atomic ratio (0.25, 0.5, 0.75, and 1) obtaining egg-shell profiles of the active components. The catalysts were characterized by X-ray diffraction, temperature-programmed techniques, such as reduction in hydrogen and desorption of ammonia, N2 physisorption, and transmission electron microscopy. The catalytic test showed that the 1,3-butadiene was selectively hydrogenated when bimetallic catalysts were used. The addition of Ni to the Pd-based catalysts suppressed n-butane formation and increased recovery of 1-butene at medium conversion. Therefore, it was observed an improved catalytic performance of the bimetallic catalysts being highest in the case of the 1NiPd/Al2O3.

Co2+, Ni2+, Zn2+ and Al3+ quaternary hydrotalcite-type materials were synthesized at: 0.33; 0.25 and 0.20 (M3+)/(M3++M2+) ratios. Then, these as-synthesized hydrotalcites were calcined and impregnated with Mo (15wt.% MoO3) and Co (3Mo:Co) to obtain the catalytic precursors. As-synthesized and impregnated calcined hydrotalcites were characterized by different physico-chemical techniques such as: X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), BET surface area measurements and NH3-temperature programmed desorption (NH3-TPD). Finally, CoMo/calcined hydrotalcites were tested in hydrodesulfurization (HDS) and hydrogenation (HYS) reactions of thiophene and cyclohexene. Results showed that the 0.25 (M3+)/(M3++M2+) ratio was the most active for the HDS reaction of thiophene, while the 0.33 (M3+)/(M3++M2+) ratio showed the best performance for the HYD reaction of cyclohexene.

The catalytic activity of Pd catalysts supported on Ce0.73Tb0.27Ox/SiO2, Ce0.6Zr0.4Ox/SiO2, Ce0.73Tb0.27Ox/La2O3-Al2O3 and Ce0.6Zr0.4Ox/La2O3-Al2O3 was studied using the reduction of NO by CO. The catalysts were characterized by X-ray fluorescence, surface area, X-ray diffraction, temperature-programmed reduction, CO chemisorption and oxygen storage capacity. Temperature-programmed reduction results indicated that Tb or Zr incorporation improves the reducibility and oxygen storage capacity. CO chemisorption data suggested the presence of large PdO particles due to the low CO/Pd ratio. No significant differences were obtained in light off temperatures (TLight off) for all Pd catalysts and the most active was 1.5%Pd/Ce0.6Zr0.4Ox/SiO2.

Natural gas, a valuable energy carrier, can be used as a fuel or as a raw material for the production of synthesis gas and hydrogen. However, significant quantities of undesirable contaminants, especially hydrogen sulfide (H2S), generate harmful environmental emissions. The objective of this work was to develop a scavenger system for the H2S removal at room temperature. The potential of mesoporous silica molecular sieve (MSU-1) supported ZnO or CuO adsorbents has been studied at room temperature for H2S removal to develop a more effective adsorbent for this important application. Zn2+ or Cu2+ loadings of 10, 20 and 30wt.% were incorporated by the incipient wetness method. The obtained solids were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), temperature programmed reduction (TPR), scanning electron microscopy (SEM) and N2 adsorption/desorption, using the BET method, to investigate their various characteristics. The MSU-1 support did not show activity for H2S removal, however the addition of copper or zinc increased the removal performance. The most active solids for H2S were 10Zn/MSU-1 (42.3mgg−1) and 20Cu/MSU-1 (19.2mgg−1). A decrease in H2S removal was observed at a zinc loading higher than 10wt.% (14.8 and 11.5mgg−1 for 20 and 30Zn/MSU-1), while 10Cu/MSU-1 presented a low adsorption capacity (10.9mgg−1) and 30Cu/MSU-1 has a similar performance than that of 20Cu/MSU-1. The adsorption capacity of the obtained materials strongly depends on the pore system as well as the well-proportioned distribution of the active phase inside the porous material and the size of metal oxide nanoparticles.