UTN- FRC -Producción Académica de Investigación y Desarrollo
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Item Esterification of succinic acid using sulfated zirconia supported on SBA-15(2021) Aguzin, Federico L.; Martínez, María Laura; Beltramone, Andrea Raquel; Padró, Cristina L.; Okulik, NoraCatalytic esterification of succinic acid with ethanol to obtain diethyl succinate (DES), a nontoxic plasticizer, is reported. Three sulfated zirconias supported on SBA-15 [SZ-SBA-15(X)] with Si/Zr molar ratios (X) of 10, 20, and 30 were syn- thesized and characterized. N2 adsorption/desorption isotherms and X-ray dif- fraction patterns evidenced preservation of the ordered mesoporous structure of the catalysts after incorporation of Zr. Yields of DES greater than 85 % were obtained at the final reaction time by using SZ-SBA-15(10) and SZ-SBA-15(20) catalysts, which were higher than those achieved with Amberlyst 36. Reuse of the SZ-SBA-15(20) catalyst showed that, even though the structure of the support was preserved, decreases in sulfur concentration and in the DES yield occurred.Item EXperimental design optimization of the ODS of DBT using vanadium oXide supported on mesoporous Ga-SBA-15(2020) Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, María Laura; Beltramone, Andrea RaquelEXperiment design-response surface methodology is applied in this work to model and optimize the o Xidation of dibenzothiophene (DBT) using VOX-Ga-SBA-15 catalyst. The analyzed variables are the influence of the nature of the catalyst (V and Ga loading), the s ubstrate/catalyst mass ratio (g DBT/g of catalyst) and the o Xidant/substrate molar ratio (H2O2/DBT). The response analyzed is conversion of DBT at 15 min of reaction time. A set of re- sponse surfaces were obtained applying the BoX-Behnken Design. Based on statistical methodology it was pos- sible to find the best arrangement between the amounts of the gallium heteroatom and the vanadium active species. The higher levels of the objective function were obtained employing the catalyst with 4 wt.% of gallium and 6 wt.% of vanadium; the optimal ratio between g DBT/g of catalyst was 4 and the molar ratio between H2O2/DBT was 5. Gallium incorporation as heteroatom in tetrahedral position allowed the better anchorage ofthe active species of vanadium, generating a very well dispersed catalyst. The optimized catalyst minimized the mass transfer limitation and moreover, was active after several recycles. The best catalyst was likewise very active for the oXidation of the most refractory sulfur compounds as benzothiophene and 4,6-dimetyldi- benzothiopene.Item Indole HDN using iridium nanoparticles supported on titanium nanotubes(2022) Ledesma, Brenda Cecilia; Martínez, María Laura; Gómez Costa, Marcos Bruno; Beltramone, Andrea RaquelThe HDN of indole was studied over iridium modified titanate nanotube catalyst. Titanium nanotube was prepared by the alkaline hydrothermal method. Iridium was added by wetness impregnation. The activity was compared with Ir–TiO2 and commercial NiMo/Al2O3 catalysts. The catalysts prepared were characterized by X-ray diffraction (XRD), N2 adsorption isotherms, UV–Vis-DRS, FTIR, XPS, TEM, Py-FTIR and H2-Chemisorption. XRD, N2 isotherms and UV–vis-DRS con- firmed the nanotube structure. The analysis showed that the mesoporous structure was maintained after Ir incorporation. The results showed that titanate nanotube as support significantly reduce the size of iridium crystallites and improves its dispersion considerably. Iridium titanate nanotube presented abundant and strong Brönsted acidity compared with TiO2 iridium catalyst. According a kinetic study, Ir–TNT was the most active catalyst for indole HDN, in mild conditions in a Batch reactor. The Brönsted acidity in synergic effect with Lewis acidity and hydrogenolysis capacity of iridium species were the responsible for the good activity.Item Iridium-supported SBA-15 modified with Ga and Al as a highly active catalyst in the hydrodenitrogenation of quinoline(2020) Ledesma, Brenda Cecilia; Martínez, María Laura; Beltramone, Andrea RaquelIr-supported SBA-15 was studied in the hydrodenitrogenation (HDN) of quinoline as a model nitrogen com- pound. The activity was improved when Si-SBA-15 support was modified with Ga and Al. Characterization of the catalysts was performed by XRD, N2 adsorption, XPS, H2 chemisorption, TEM, TPR, NMR and Py-FTIR. Dispersion and nature of the iridium species are dependent parameters on the support characteristics. Better activity for the elimination of the nitrogen atom was observed with Ir-Ga-SBA-15 as compared to Ir-Al-SBA-15 at 250 and 300 °C. However, the TON value for Ir-Al-SBA-15 was higher than Ir-Ga-SBA-15 at 300 °C, indicating the influence of the stronger Bronsted acidity in the elimination of the nitrogen atom at higher temperature. The enhanced activity was attributed to the particularly good dispersion of the iridium catalytic centers and to the synergic effect of Bronsted and Lewis acid sites, derived from Ga or Al incorporation. Ga-SBA-15 with 1 wt.% of iridium loading was the most active catalyst for HDN of quinoline. 95% of nitrogen elimination was attained at short time in mild conditions. The reusability of the catalyst presents it as potential catalyst for HDN process.Item Iron-modified mesoporous materials as catalysts for ODS of sulfur compounds(2020) Rivoira, Lorena Paola; Juárez, Juliana María; Martínez, María Laura; Beltramone, Andrea RaquelFe-modified mesoporous catalysts were used in the ODS of DBTs using H2O2 as oXidant and acetonitrile as solvent. SBA-15, MCM-48, CMK-3 and CMK-1 were used as supports. Iron was incorporated using iron nitrate by wetness impregnation. The catalysts were characterized by XRD, N2 isotherms, TEM, XPS and ICP. We developed catalysts with high specific surface area, pore volume and narrow mesopore size distribution and highly dis- persed Fe- species. The catalysts were tested in the o Xidative desulfurization of different sulfur compounds as benzothiophene, dibenzothiopene and 4,6-dimethyl dibenzothiopene. The catalyst prepared using CMK-3 as support was the most active for the ODS reaction. The good activity was related with the high dispersion of the iron oXides, mainly in the magnetite phase. Temperature, hydrogen peroXide and sulfur initial concentration were studied using Fe-CMK-3 in the oXidation of DBT. The optimal operation conditions were determined. Fe- CMK-3 is an active and stable catalyst to be applied in the industrial process of ODS.Item Multiple-wall carbon nanotubes obtained with mesoporous material decorated with ceria-zirconia(2020) Rodríguez, Miguel Angel; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel; Martínez, María LauraIn this work, Ceria-Zirconia on ordered Santa Barbara mesoporous silica (Ce-Zr-SBA-15), has been used directly as a catalyst for the synthesis of carbon nanotubes (CNTs) through Chemical Vapor Deposition (CVD). In addition to cerium oxide, it contains zirconium oxide nano crystallites, which act as catalysts for carbon nanostructures. The catalytic performance of this material was evaluated for the decomposition of ethanol at 900 °C, with N2 flow. The carbon decomposed from absolute ethanol diffuses through the surface of the nanostructured catalytic material and precipitates in the form of MWCNT structures, which could be identified by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), showing average diameters of 30–35 nm.Item Hydrodenitrogenation of indol using iridium catalyst supported on titanium nanotubes(2022) Ledesma, Brenda Cecilia; Martínez, María Laura; Gómez Costa, Marcos Bruno; Beltramone, Andrea RaquelThe HDN of indole was studied over iridium modified titanate nanotube catalyst. Titaniun nanotube was prepared by the alkaline hydrothermal method. Iridium was added by wetness impregnation. The activity was compared with Ir-TiO2 and commercial NiMo/Al2O3 catalysts. The catalysts prepared were characterized by X-ray diffraction (XRD), N2 adsorption isotherms, UV–Vis-DRS, XPS, TEM, Py- FTIR and H2-Chemisorption. XRD, N2 isotherms and UV–vis-DRS confirmed the nanotube structure. The analysis showed that the mesoporous structure was maintained after Ir incorporation. The results showed that titanate nanotube as support significantly reduce the size of iridium crystallites and improves its dispersion considerably. Iridium titanate nanotube presented abundant and strong Bronsted acidity compared with TiO2 iridium catalyst. Ir-TNT was the most active catalyst for indole HDN, in mild conditions in a Batch reactor. The Bronsted acidity in synergic effect with Lewis acidity and hydrogenolysis capacity of iridium species were the responsible for the good activity.The HDN of indole was studied over iridium modified titanate nanotube catalyst. Titaniun nanotube was prepared by the alkaline hydrothermal method. Iridium was added by wetness impregnation. The activity was compared with Ir-TiO2 and commercial NiMo/Al2O3 catalysts. The catalysts prepared were characterized by X-ray diffraction (XRD), N2 adsorption isotherms, UV–Vis-DRS, XPS, TEM, Py- FTIR and H2-Chemisorption. XRD, N2 isotherms and UV–vis-DRS confirmed the nanotube structure. The analysis showed that the mesoporous structure was maintained after Ir incorporation. The results showed that titanate nanotube as support significantly reduce the size of iridium crystallites and improves its dispersion considerably. Iridium titanate nanotube presented abundant and strong Bronsted acidity compared with TiO2 iridium catalyst. Ir-TNT was the most active catalyst for indole HDN, in mild conditions in a Batch reactor. The Bronsted acidity in synergic effect with Lewis acidity and hydrogenolysis capacity of iridium species were the responsible for the good activity.