An investigation on mechanism for aromatization of n-hexane on Zn/HZSM-5 catalyst

The aromatization of n hexane over Al 2O 3, Zn/Al 2O 3 and HZSM 5 was compared. Influence of zinc content and hydrothermal treatment on aromatization properties of Zn/HZSM 5 was investigated. It was found that B acid is indispensable active centre for n hexane aromatization while Al L acid shows very weak activation to n hexane. Incorporation of zinc onto surface of HZSM 5 greatly enhances the its aromatization activity. When zinc content exceeds 1 8%, it has little effect on aromatization properties of Zn/HZSM 5. There exists synergistic interaction between B acid sites and Zn L acid sites on Zn/HZSM 5 catalyst, which is necessary to enhancement of aromatization performance of HZSM 5. Mechanism for n hexane aromatization on Zn/HZSM 5 catalyst is proposed on the basis of the experimental results.