Synthesis of Zeolite ZSM-10 and Catalytic Evaluation of Pt/K-ZSM-10 for n-Hexane Aromatization.

Abstract

The synthesis of zeolite ZSM-10 with the MOZ topology and the catalytic properties of platinum supported K+ exchanged of ZSM-10 (Pt/K-ZSM-10) for the aromatization of n-hexane are presented. When the 1,4-diazocyclo[2,2,2]octane (1,4-dimethyl DABCO) hydroxide is used as an organic structure-directing agent together with K+, crystallization of pure ZSM-10 is very sensitive not only to the Si/Al molar ratio, but also to the concentration of K2O in the synthesis mixture. The physicochemical properties of Pt/K-ZSM-10 and its catalytic properties for the aromatization of n-hexane are compared with those obtained from Pt/K-L, which is the commercialized catalyst for this process. Although, when Pt loading level was fixed to be ca. 1.0 wt%, Pt/K-ZSM-10 and Pt/K-L shows comparable Pt dispersion levels, Pt/K-ZSM-10 was found to show the lower n-hexane aromatization activity, due to Pt clusters easily migrate to the external surface of the zeolite catalyst. The overall characterization and catalytic results of this work demonstrate that nanocrystallity of ZSM-10 is one of the most crucial factors influencing location of platinum and thus n-hexane activity.