A dual-templating synthesis strategy to hierarchical ZSM-5 zeolites as efficient catalysts for the methanol-to-hydrocarbons reaction

\u3cp\u3eA novel dual-templating synthesis strategy is presented to obtain hierarchical ZSM-5 zeolite using a combination of known structure-directing agents for ZSM-5 synthesis and C\u3csub\u3e16\u3c/sub\u3eH\u3csub\u3e33\u3c/sub\u3e-[N\u3csup\u3e+\u3c/sup\u3e-methylpiperidine] (C\u3csub\u3e16\u3c/sub\u3eMP) as mesoporogen. C\u3csub\u3e16\u3c/sub\u3eMP is a cheap surfactant, which can be obtained in a single step by alkylation of N-methylpiperidine. The zeolite materials were extensively characterized for their textural and acidic properties and evaluated on the basis of their ability to convert methanol to hydrocarbons. Bulk and nanosheet (di-quaternary ammonium surfactant) ZSM-5 zeolites served as reference materials. Hierarchical ZSM-5 zeolite can be obtained in this way with diethylamine, n-propylamine, 1,4-diaminobutane, 1,6-diaminohexane. In particular, the combination with diethylamine afforded a material that displayed similar performance in the methanol-to-hydrocarbons reaction as nanosheet ZSM-5. The optimum ZSM-5 zeolite is highly crystalline, contains a large mesopore volume and few silanol groups and external Brønsted acid sites, which contributes to the low rate of deactivation.\u3c/p\u3