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A highly efficient and environmentally friendly approach for the synthesis of 1,8-dioxo- octahydroxanthenes has been developed catalysed by a supported cobalt nanoparticle catalyst (CoNP@SBA-15) in water. The use of this heterogeneous catalytic system offered several advantages including high yields, low catalyst loading, short reaction times and easy workup. Furthermore, the catalyst was efficiently reused for ten consecutive cycles without any significant loss in catalytic activity.

Esta tesis se basa en producir carbonatos de polipropileno en reacciones de copolimerización utilizando dos tipos diferentes de catalizadores heterogéneos: Glutarato de zinc (ZnGA) y catalizadores Double Metal Cyanide (DMC). Se ha hecho un estudio completo de ambos catalizadores además de la caracterización de los policarbonatos obtenidos en las reacciones. Uno de los aspectos más interesantes de este estudio es el uso del dióxido de carbono (CO2), no sólo como medio de presurización de la reacción sino también como fuente de alimentación de carbonos (C1). El dióxido de carbono es una de las principales fuentes que causan el efecto invernadero. De cara a atacar y solucionar este problema, el CO2 (subproducto de numerosos procesos industriales) ha sido capturado, almacenado y utilizado (e insertado) en reacciones de copolimerización. Estas reacciones, las cuales son llevadas a cabo en condiciones subcríticas y en modo batch, se denominan reacciones de copolimerización puesto que implican la utilización de dos monómeros como reactivos: óxido de propileno y dióxido de carbono., Departamento de Ingeniería Química y Tecnología del Medio Ambiente, Doctorado en Ingeniería Química y Ambiental

A bifunctional nanocatalyst composed of iron containing SBA-15 material modified with sulfonic acid groups was synthesized by a mechanochemical approach. A full characterization of the obtained nanocatalyst was performed by N2 physisorption isotherms analysis, transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and Fourier-Infrared Spectroscopy (FT-IR). The mechanochemically synthesized nanocatalyst displays a high isoeugenol conversion to vanillin under mild conditions using H2O2 as oxidizing agent. Interestingly, this conversion resulted to be higher than that one obtained with the same material synthesized by an impregnation method. Additionally, the nanocatalyst showed excellent reusability over four successive runs under the studied reaction conditions.

An immobilized copper Schiff base tridentate complex was prepared in three steps from SBA-15 supports. The immobilized copper nanocatalyst (heterogeneous catalyst) was characterized by Fourier transform infrared spectroscopy (FT-IR), cross polarization magic angle spinning (CP-MAS), 13-carbon nuclear magnetic resonance (13C-NMR), atomic absorption spectroscopy (AAS), thermogravimetric analysis (TGA), and N2-physisorption. Moreover, morphological and structural features of the immobilized nanocatalyst were analyzed using transmission electron microscopy (TEM) and X-ray powder diffraction spectrometry (PXRD). After characterizing the nanocatalyst, the catalytic activity was determined in hydrogen peroxide (H2O2) decomposition. The high decomposition yield of H2O2 was obtained for low-loaded copper content materials at pH 7 and at room temperature. Furthermore, the nanocatalyst exhibited high activity and stability under the investigated conditions, and could be recovered and reused for at least five consecutive times without any significant loss in activity. No copper leaching was detected during the reaction by AAS measurements.

Zn-Co double metal cyanide (DMC) catalysts were prepared by varying the initial amounts of ZnCl2 to analyze the influence of method of preparation on the different copolymerization parameters. Synthesized catalysts were analyzed by different techniques, infrared spectrometry and inductively coupled plasma optical emission spectrometry, scanning electron microscopy, N2-physisorption and X-ray diffraction to determine whether characteristics affect the catalytic activity. The copolymers were characterized by infrared spectrometry and gel permeation chromatography. Highly active catalyst (2.5 kg polymer/g catalyst) was synthesized, low amounts of cyclic carbonate byproduct were produced (0.4 %) with medium crystallinity catalysts and considerable amounts of K+ (0.4% to 1.0%wt)., CTQ2015-64892-R (MINECO/FEDER)

CuO/MgAl2O4 and CuO/MgFe2O4 catalysts were successfully synthesized with the use of spinel supports by a very simple and low-cost mechanochemical method. High-speed ball-milling was used to synthesize these catalyst supports for the first time. Materials were subsequently characterized by using XRD, FESEM, TEM, EDS-Dot mapping, XPS, BET-BJH, and Magnetic Susceptibility to investigate the physical-chemical characteristics of the catalysts. Acidity evaluation results indicated that the catalyst with the Mg-Al spinel support had more acid sites. XRD results showed a successful synthesis of the catalysts with large crystal sizes. Both catalysts were used in isoeugenol oxidation and vanillyl alcohol to vanillin reactions, with the CuO/MgAl2O4 showing optimum results. This catalyst provided 67% conversion (74% selectivity) after 2 h and this value improved to 81% (selectivity 100%) with the second reaction after 8 h. The CuO/MgFe2O4 catalyst in the first reaction after five hours revealed 53% conversion (47% selectivity) and after eight hours with the second reaction, the conversion value improved to 64% (100% selectivity). In terms of reusability, CuO/MgAl2O4 showed better results than the CuO/MgFe2O4 catalyst, for both reactions.