Abstract
A 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 C16H33-[N+-methylpiperidine] (C16MP) as mesoporogen. C16MP 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.
Highlights
Zeolites are crystalline microporous aluminosilicates, widely used for acid-catalyzed reactions in the chemical industry [1,2,3,4,5,6,7]
A 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 C16H33-[N+-methylpiperidine] (C16MP) as mesoporogen
Peak broadening points to reduced crystal size dimensions, as exemplified by the X-ray diffraction (XRD) pattern of MFI-sheet, prepared using a diquaternary ammonium surfactant [15,24], and is observed for ZSM-5 zeolites obtained by a combination of C16MP with DAB, DAH or DEA
Summary
Zeolites are crystalline microporous aluminosilicates, widely used for acid-catalyzed reactions in the chemical industry [1,2,3,4,5,6,7]. An appealing illustration of this approach is to synthesis of ZSM-5 zeolite nanosheets by diquaternary ammonium surfactants developed by Ryoo’s group [24]. In these nanosheets, the crystal size is limited to several nanometers in the b-direction. The benefit of nanosheets has been demonstrated for many catalytic reactions We report a novel dual-templating synthesis of ZSM-5, which yields directly an optimum hierarchical material with similar catalytic performance as ZSM-5 nanosheet synthesized by diquaternary ammonium surfactants. The obtained zeolites were extensively characterized for their morphological, textural and acidic properties by elemental analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Ar porosimetry, infrared (IR) spectroscopy and solid state nuclear magnetic resonance (NMR) spectroscopy
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call