Effects of hierarchical zeolites on aromatization of acetylene

Abstract

The conventional zeolites and the hierarchical zeolites were employed to investigate the catalytic performance of aromatization from acetylene. In the case of the conventional MCM-22 zeolites, the effects of their Si/Al ratio on the catalytic performance were investigated by considering the conversion of acetylene, the selectivity of aromatics, and the formation of cokes. By swelling the interlayers in the MCM-22 precursor followed by pillaring the swollen spaces, hierarchical zeolites with layered nanosheets (i.e., MCM-36) were successfully prepared, characterized and tested for aromatization. With the novel hierarchical zeolite-based catalysts, the effects of structural difference as well as the Si/Al ratio were scrutinized. From the catalytic activity tests, the selectivity towards aromatic compounds through MCM-36 was significantly improved, and the amount of carbon deposition was decreased a lot, probably due to the increased number of external Bronsted acid sites. To draw such conclusion, several characterization techniques were also applied and the results were analyzed. The techniques included physisorption, XRD, FT-IR, TEM, SEM, EDX methods.