Examinando por Autor "Bustamante, Tatiana M."

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    Catalytic pyrolysis of used tires on noble-metal-based catalysts to obtain high-value chemicals: Reaction pathways
    (Elsevier B.V., 2022-07-01) Osorio Vargas, Paula; Campos, Cristian H.; Torres, Cecilia C.; Herrera, Carla; Shanmugaraj, Krishnamoorthy; Bustamante, Tatiana M.; Diaz de Leon, J.N.; Medina, Francisco; Arteaga Pérez, Luis E.
    A systematic study on the use of noble metals (Pd, Pt, Au) supported on titanate nanotubes (NT-Ti) for selectively producing BTX and p-cymene from waste tire pyrolysis is provided here. All the materials were characterized for chemical, textural and structural properties using a range of analytical techniques. The M/NT-Ti (M: Pd, Pt, or Au) catalysts exhibit low nanoparticle sizes (1.8 support > non-catalyst. The Py-GC/MS suggest that the catalysts participate in the secondary reactions of dealkylation, dehydrogenation, isomerization, aromatization, and cyclization leading to a higher formation of BTX than the uncatalyzed reaction. Finally, a comprehensive reaction pathway describing the catalytic pyrolysis of WT over Pd/NT-Ti was proposed by studying the catalytic pyrolysis of individual polymers constituting the waste tires, and D,L-Limonene. © 2021 Elsevier B.V.
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    Cobalt Nanoparticles Supported on TiO2 for Highly Selective Formation of N-Benzylideneanilines from Nitroarenes and Benzaldehyde via Reductive Imination Reaction
    (MDPI, 2024-04-04) González-Vera, Daniela; Bustamante, Tatiana M.; Díaz de León, J. Noé; Torres, Cecilia C.; Campos, Cristian H.
    The search for active, inexpensive, and stable heterogeneous catalysts to produce desired imines in fine chemistry presents an ongoing challenge for both academia and industry. This work reports the utilization of Co nanoparticles supported on TiO2 derived from the H2-assisted reduction of the perovskite-type mixed oxide CoTiO3. The entire preparation process is operationally simple and straightforward, enabling scalability for practical applications. The resulting catalyst comprises metallic cobalt nanoparticles responsible for the hydrogenation process, whereas the TiOx thin layer surrounding the cobalt promotes the adsorption of C=O, thereby enhancing the formation of desired products. Notably, at lower temperatures, the reaction yields the target imine product. Our study demonstrates a synergistic effect between nitrobenzene and benzaldehyde in the presence of a Co-TiOx interface, which reduces the apparent activation energy for the hydrogenation of the-NO2 group. Furthermore, under moderate reaction conditions, the catalytic system offers applicability to various nitrobenzene compounds substituted at the 4-position and benzaldehyde, resulting in high yields of the corresponding imines with electron-density-donating substituent groups. Finally, the catalyst exhibits facile separation for subsequent reuse, displaying moderate stability with minimal selectivity for the desired product.
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    Liquid Phase Hydrogenation of Pharmaceutical Interest Nitroarenes over Gold-Supported Alumina Nanowires Catalysts
    (MDPI AG, 2020-02) Shanmugaraj, Krishnamoorthy; Bustamante, Tatiana M.; Campos, Cristian H.; Torres, Cecilia C.
    In this work, Au nanoparticles, supported in Al2O3 nanowires (ANW) modified with (3-aminopropyl)trimethoxysilane were synthetized, for their use as catalysts in the hydrogenation reaction of 4-(2-fluoro-4-nitrophenyl)-morpholine and 4-(4-nitrophenyl)morpholin-3-one. ANW was obtained by hydrothermal techniques and the metal was incorporated by the reduction of the precursor with NaBH4 posterior to superficial modification. The catalysts were prepared at different metal loadings and were characterized by different techniques. The characterization revealed structured materials in the form of nanowires and a successful superficial modification. All catalysts show that Au is in a reduced state and the shape of the nanoparticles is spherical, with high metal dispersion and size distributions from 3.7 to 4.6 nm. The different systems supported in modified-ANW were active and selective in the hydrogenation reaction of both substrates, finding for all catalytic systems a selectivity of almost 100% to the aromatic amine. Catalytic data showed pseudo first-order kinetics with respect to the substrate for all experimental conditions used in this work. The solvent plays an important role in the activity and selectivity of the catalyst, where the highest efficiency and operational stability was achieved when ethanol was used as the solvent