Banca de QUALIFICAÇÃO: MARCELA MAGALHÃES DE PAULA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MARCELA MAGALHÃES DE PAULA
DATE: 17/08/2021
TIME: 20:00
LOCAL: meet.google.com/tks-hues-kwk
TITLE:

ACETONITRILE SELECTIVE CATALYTIC OXIDATION ON CERIA CATALYST SYNTHESIZED BY PECHINI METHOD

KEY WORDS:

Selective Catalytic Oxidation. Acetonitrile. Pechini method.

PAGES: 101
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Inorgânicos
SUMMARY:

Given the growing concern about an atmospheric proliferation caused by the emission of greenhouse gases and volatile compounds, such as ammonia, carbon monoxide and nitrile gases, several alternatives have emerged to contain it. Among the technologies already used to solve this problem, in the present work the selective catalytic oxidation of acetonitrile was applied over the catalysts CeO2 and CeO2-CuO. In which the focus was to evaluate the performance of these metal oxides synthesized by the Pechini method and as their only selectivities in N2 and CO2 production. In view of the efforts aimed at obtaining favorable catalysts for the oxidation reaction, they were considered as conditioning factors of the method that contribute to the performance of the synthesized material. Among these possible variables, such as pH range, prepared polyalcohol, ratio between complex acids and cations, the influence of the chelating agent (carboxylic acid) on the final properties of the catalysts was analyzed. In this case, citric acid, malic acid and oxalic. Furthermore, the impact of the addition of copper oxide II in the catalysts on the reaction was also studied. Finally, the effect of these variants on the formed materials was investigated through characterization techniques, such as X-ray diffraction (XRD) and physisorption with N2 (B.E.T. method). XRD standards identified the presence of CeO2 in the prepared catalysts. It was also noted that the deposition of CuO in the synthesized materials did not change its structure. The analysis of physiosorption with N2 provided isotherm profiles that varied between pure and doped, in addition to demonstrating that catalysts synthesized with oxalic acid (CeOx and CeOxCu) had the largest specific areas. On the other hand, those synthesized with malic acid (CeMa and CeMaCu) and citric acid (CeCi and CeCiCu) have higher pore volumes and sizes. Furthermore, in the catalytic tests conducted in the range of 100-600 ºC for 1 hour, high acetonitrile requirements were identified for these catalysts at low temperatures, starting at 100 ºC and reaching total conversion at 250°C to CeMa and 340 °C for CeCi. However, CeOx will start its conversion at a higher temperature, from 300 °C, reaching 100% around 400 °C. On the other hand, with the addition of copper, an increase in the reagent decomposition temperature was found, and thus, an inversion in the yield of these materials, with emphasis on CeCiCu (350 ºC) which had the lowest conversion temperature, followed by CeCiOx (500 ºC) and finally CeMaCu which converted 90% to 600 ºC. As for the selectivity to N2 and CO2, CeMa and CeCi had better results, however, it presented traces of NO and NH3. Furthermore, for the doped materials, CeCiCu and CeOxCu stood out with high selectivity in CO2, followed by N2. But it also had access to NH3, as happened to CeMaCu. However, the latter, we also present traces of NO. That said, it is possible to infer that CeMa exhibited the best results for OCS-CH3CN because it could combine good conversion at reduced temperature, high selectivity to N2 and CO2 and low formation of undesirable by-products. The other catalysts were somehow less selective to N2 and CO2, or generated some kind of secondary source.

BANKING MEMBERS:
Interno - 1759475 - JORGE DAVID ALGUIAR BELLIDO
Interno - 1863340 - EDUARDO PRADO BASTON
Interno - 1810291 - DEMIAN PATRICK FABIANO