Persona: Calvino Casilda, Vanesa
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Calvino Casilda
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Publicación The role of gold dopant in AP-Nb/MCF and AP-MCF on the Knoevenagel condensation of ethyl cyanoacetate with benzaldehyde and 2,4- dichlorobenzaldehyde(Elsevier, 2019-03-15) Sobczaka, Izabela; Wolskia, Lukasz; Siodlaa, Tomasz; Ziolek, María; Calvino Casilda, Vanesa; Martín Aranda, Rosa MaríaThe Knoevenagel condensation with chlorine substituted benzaldehyde is difficult because of deactivation of aldehyde group. In this work we have shown that the activity of mesoporous cellular foams (MCF and Nb/MCF), modified with 3-aminopropyl-trimethoxysilane (AP) as a source of basicity, can be enhanced for this reaction by the anchoring of gold species. Gold species were loaded on amine modified materials towards Au/AP-MCF and Au/AP-Nb/MCF. Moreover, copper was used as a dopant for the latter sample giving rise to AuCu/AP/MCF. All these materials were characterized in details by different complementary techniques (N2 adsorption isotherms, TEM, UV–vis, TG/DTA, XPS, DFT calculations) which allowed the evaluation of states of all components of the catalysts. The interaction between niobium species and AP was evidenced to increase the stability of the basic modifier. This interaction was weakened by the introduction of gold and copper. The presence of both, negatively charged gold nanoparticles (NPs) and gold cations was crucial for the activation of 2,4-dichlorobenzaldehyde via the interaction with chlorine substituent atoms and aldehyde oxygen atoms as well as breaking of the “pseudo hydrogen bond” between aldehyde hydrogen atom and chlorine substituent, which destabilized the structure making it more active. Gold dopants did not influence significantly the condensation of ethyl cyanoacetate with benzaldehyde.Publicación Impact of Brønsted acid sites in MWW zeolites modified with cesium and amine species on Knoevenagel condensation(Elsevier, 2019-05-15) Wojtaszek Gurdak, Anna; Grzesinska, Aneta; Ziolek, María; Calvino Casilda, Vanesa; Martín Aranda, Rosa MaríaLayered zeolites of MWW family, MCM-22 and pillared MCM-36, were used as supports for base modifiers: cesium species (introduced via cation exchange or impregnation) and 3-aminopropyl trimethoxysilane (AP). The obtained materials were characterized by different methods (ICP-OES, N2 adsorption, XRD, XPS, TG/DTA, FTIR combined with pyridine adsorption, 2-propanol decomposition) for evaluation of chemical, structural and surface properties. All materials obtained were subjected to the Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate and ethyl acetoacetate. The effect of the zeolite structure, the stability of the catalysts as well as acid-base properties of zeolites on the activity in Knoevenagel condensation were considered. Of particular interest was the role of Brønsted acid sites (BAS). The nature of basic sites and BAS played different roles depending on the methylene compound used in the Knoevenagel condensation. AP-modified zeolites were the most active in the condensation between benzaldehyde and ethyl cyanoacetate, in which, in the first step of the reaction AP abstracted hydrogen from methylene carbon in ethyl cyanoacetate. A different reaction pathway was postulated for the condensation with ethyl acetoacetate on the basis of the highest activity of unmodified zeolites and the relationship between benzaldehyde conversion and the number of BAS. For this reaction protonation of benzaldehyde was postulated as the initial step of the reaction.Publicación Ordered mesoporous molecular sieves as active catalyts for the synthesis of 1,4-dihydropyridine derivatives(Elsevier, 2020-09-01) Calvino Casilda, Vanesa; Martín Aranda, Rosa MaríaResearch on heterocyclic compounds with biological and pharmacological activity continues to arouse great interest. The study of 1,4-dihydropyridines (1,4-DHPs) is of particular interest in the pharmaceutical field due to their important applications as calcium channel antagonists for the treatment of heart diseases. The implementation of novel heterogeneous catalysts to optimize Hantzsch synthesis, such as ordered mesoporous molecular sieves, is an efficient and eco-friendly proposal that still requires a lot of work. The remarkable features of ordered mesoporous molecular sieves, such as high surface area, tailored porosity, chemical and thermal stability, among others, turn these materials into powerful solid catalysts capable of selectively leading the synthesis of 1,4-DHPs. In addition, the combination of ordered mesoporous molecular sieves and process intensification for the synthesis of 1,4-DHP derivatives is still a research field in development. Therefore, promote greener methodologies in the synthesis of 1,4-DHPs that can be extended to any organic synthesis in fine chemical production is an important goal yet to be achieved.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.