Conversão de etanol a produtos de maior valor agregado sobre óxidos de nióbio de zircônio modificados

Abstract

Several compounds can be obtained using ethanol as a resource. Among these, the interest in the ones obtained from ethanol dehydrogenation is growing, as ethyl acetate, butadiene and butanol. Catalysts Nb2O5/ZrO2, Cu-Nb2O5/ZrO2 and AgNb2O5/ZrO2 were prepared by incipient wetness impregnation and evaluated for ethanol conversion. The catalysts were characterized by FRX, DRX, BET, TPR-H2, TPD-NH3 and TPD-CO2 to investigate their textural, structural, acid-base and redox properties. The catalytic activity and product distribution were investigated in different temperatures (300-450 °C) and space velocities (0,4-15,6 h-1 ). Catalytic testes showed that the increase in temperature favored ethanol dehydration, increasing ethylene molar percentage and reducing acetaldehyde percentage. However, the addition of silver and copper promoted ethanol dehydrogenation, obtaining high percentages of acetaldehyde in 300 °C. At this temperature, it was observed that butadiene and ethyl acetate were increased, while acetaldehyde was reduced when the space velocity was reduced. Therefore, this study was interesting to better understand the proper reaction conditions to obtain the desired products, but the catalysts showed most acid sites, leading to high formation of dehydration products, ethylene and diethyl ether.