An investigation on the catalytic performance of 10 MR zeolites in methanol aromatization reaction

Five zeolites ZSM-5, ZSM-22, EU-1, MCM-22, and ITQ-13 with 10 member ring channels were hydrothermally synthesized and their structure, acidity, morphology and catalytic behaviors in methanol aromatization reaction were compared. The results indicate that the morphology, microporous volumes, and physicochemical properties of the zeolites differ significantly from each other, and thus results in considerable influence on the catalytic activity and stability. Among the five zeolites studied, ZSM-5 shows the highest aromatic yield of 34.8%, followed by MCM-22 with the aromatic yield of 21.9%. However, unlike ZSM-5 and MCM-22, the other three catalysts are inactivitive for methanol aromatization. The introduction of Ga species into ZSM-5 and MCM-22, however, can improve the aromatic yield significantly. The aromatic yields on Ga/ZSM-5 and Ga/MCM-22 reach 40.8% and 27.1%, respectively. The TG/DTA and GC analyses of the coke compounds deposited on the deactivated catalysts suggest that the five zeolites display much differences in composition, location and distribution of coke deposition.