UTN- FRC -Producción Académica de Investigación y Desarrollo - Artículos

Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/2453

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Author: search.filters.author.Martínez, María LauraSubject: search.filters.subject.Gallium

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    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 Raquel
    EXperiment 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.
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    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 Raquel
    Ir-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.