Solvothermal Synthesis and Characterization of Large-Crystal All-Silica, Aluminum-, and Boron-Containing Ferrierite Zeolites

摘要

Large crystals of all-silica, aluminum-, and boron-containing ferrierite zeolites were synthesized using a solvothermal synthesis method and a fluoride medium. Alkylamines, namely, propylamine, butylamine, and pentylamine were employed as templates in the syntheses. The products were characterized by powder X-ray diffraction (XRD), inductively coupled plasma-optical emission spectrometry (1CP-OES), thermogravimetric analysis (TGA), elemental (CHN) analyses, scanning electron microscopy (SEM), N2-adsorption, and ~1H, ~11B, ~(27)A1, as well as ~(29)Si MAS NMR spectroscopy. The ~(27)Al and ~(11)B MAS NMR spectroscopic investigations revealed that aluminum and boron were successfully incorporated into the FER-type framework. SEM indicated the occurrence of crystals with a size of up to about 600 μm. Furthermore, for all-silica and boron-containing ferrierite zeolites, the shape, size, and thickness of the crystals could be controlled by increasing the chain length of the alkyl group in the alkylamine and the crystallization time. Aluminum-containing ferrierite zeolites could be synthesized with a rectangular morphology exclusively. Observation of transient guest profiles during methanol uptake by means of IR microscopy exemplifies the possibility of directly observing diffusion anisotropy in FER-type frameworks.