Novel Composite Catalysts Efficiently Catalyze C8 Aromatics by Controlling the Reaction Pathway

Abstract

Pt-3Si/Z20 and 3La/Z113 catalysts were prepared by modifying high Si/Al ratio ZSM-5 and low Si/Al ratio ZSM-5, respectively. Here, a high-performance composite catalyst was prepared by combining two catalysts (Pt-3Si/Z20 and 3La/Z113) with different functions. Many techniques were performed to characterize the catalysts. The composite catalyst has multiple active sites with different functions by integrating the properties of the two catalysts. The efficient synergistic effects of dealkylation and isomerization are applied to the complex C8 aromatics reaction. The reaction pathways of ethylbenzene, m-xylene, and o-xylene in C8 aromatics were successfully controlled. Additionally, we found that the different spatial arrangements of the two catalysts had effects on the xylene losses of the catalysts. This could be attributed to the disproportionation of p-xylene during the reaction. At 360 °C, EB conversion, PX yield, and xylene loss were 71.6%, 23.2%, and 1.75%, respectively. This work has important guiding significance for the industrial production of p-xylene.