Persona: Calvino Casilda, Vanesa
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0000-0002-2756-2164
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Calvino Casilda
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Vanesa
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Publicación Hierarchically organized metal supported carbon catalysts for C-C bond forming reactions(Elsevier, 2022-10-12) Martín García, Seila; Rubio Marcos, Fernando; Calvino Casilda, VanesaThe preparation of heterogeneous catalysts is decisive to the development of catalytic processes that are environmentally acceptable. Therefore, the methodology used in the preparation of such catalysts is a key factor in the development of high catalytic activity and with concern to environmental value. Herein, we report the design of catalysts by dispersing nanoparticles of cobalt oxide (Co 3O4 ) on micrometric supports of zinc oxide (ZnO) and activated carbon (AC) using a fast and green methodology free of waste and solvents and with a low-energy consumption. In particular, the partial reaction that takes place, at room temperature, between both metal oxides and between these oxides and AC, due to proximity and diffusion effects of the corresponding materials, results in the formation of different interfaces (ZnCo, ZnAC, CoAC Co-Co). Specifically, such interfaces are new reactive surfaces that lead to very interesting and innovative properties. Thus, depending on its application, it is possible to control and modify the catalytic properties (activity / conversion / selectivity) of a solid by tuning surface and interface. This fact is proved in the model reaction of Knoevenagel condensation between aldehydes and malonic esters. Therefore, our results prove that controlling the interfaces is a feasible way to achieve in the Knoevenagel condensation, which is a reaction widely used in the formation of C–C bonds for the organic synthesis of important intermediates and final products.Publicación Porous Alkaline‑Earth Doped Multiwall Carbon Nanotubes with Base Catalytic Properties(Springer, 2019-05-04) Barrios‑Bermúdez, N.; Santos‑Granados, J; Cerpa‑Naranjo, A; Rojas‑Cervantes, M.L.; Moreno, Rodrigo; Calvino Casilda, VanesaAlkaline-earth doped multiwall carbon nanotubes, M-CNT (M=Mg, Ca, Sr, Ba) have been prepared by a combined method of ionic exchange and precipitation. The wide characterization of the solids by nitrogen adsorption, ATR–FTIR, thermal analysis, XRD, scanning electron microscopy, transmission electron microscopy, point of zero charge (PZC), and X-ray photoelectron spectroscopy shows that the incorporation of M to the CNTs has been successfully produced. The doping with the alkaline-earth cations causes a decrease in the SBET value of the raw material, mainly due to the blockage of mesopores by the metal carbonate phase formed in most of cases. This metallic phase also contributes to the destabilization of the nanotubes by promoting their oxidation. According to PZC values, the acid character of oxidized CNTs changes to basic for the M-CNT series, Mg-CNT showing the highest PZC value. The basic properties of the catalysts have been tested in the C–C bond forming reaction of Knoevenagel, by carrying out the condensation of ethyl cyanoacetate with benzaldehyde or 4-methoxybenzaldehyde.Publicación Metal-free synthesis of quinolines catalyzed by carbon aerogels: Influence of the porous texture and surface chemistry(Elsevier, 2017-04-17) Godino Ojer, Marina; Soriano, Elena; Calvino Casilda, Vanesa; Maldonado-Hódar, Francisco J.; Pérez Mayoral, María ElenaWe report herein an experimental and theoretical study of the Friedländer reaction, from 2-amino-5-chlorobenzaldehyde and ethyl acetoacetate, catalyzed by free-metal nanocatalysts based on carbon aerogels, to afford quinoline 3a. The developed methodology implies the combined use of carbon aerogels with solvent-free technologies under MW irradiation yielding the corresponding quinoline with moderated yield (66%) in only 5 min of reaction time. Our results demonstrated that the reactivity of the samples upon MW irradiation is strongly dependent on the porosity and surface chemistry of the carbon aerogels, the most active catalytic species being the most acidic oxygenated functional groups, –CO2H groups originated by oxidant treatment, or even in situ by hydrolysis of –CO–O–CO–, over the carbon surface. The theoretical investigation of the reaction mechanism, by using computational methods, demonstrated that the synthesis of quinoline 3a in the absence or in the presence of carbon aerogels takes place by aldolization, subsequent heterocyclization and finally double dehydration. Relatively strong π-π stacking interactions between carbon support and reagents could be behind of the observed catalytic performance also extended for the oxygenated models. Furthermore, the concentration of –CO2H groups over the carbon surface is a key factor favoring each step of the reaction but acting as individual catalytic sites.