Controllable synthesis of ZSM-11/ZSM-5 intergrowth zeolite using 1,3-cyclohexanedimethanamine as organic template
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Controllable synthesis of ZSM-11/ZSM-5 intergrowth zeolite using 1,3-cyclohexanedimethanamine as organic template Zhendong Wang1 · Yi Luo1 · Xiangcheng Li1 · Weimin Yang1
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract A new organic template, 1,3-cyclohexanedimethanamine (1,3-CDA), is found to be effective in directing the crystallization of ZSM-11 zeolite. Phase transformation from ZSM-11 to ZSM-5 was observed when varying the molar ratios of OH−/SiO2, Na+/SiO2 and S iO2/Al2O3. ZSM-11/ZSM-5 intergrowth zeolites with ZSM-5 contents from 10 to 100% were synthesized. The structural intergrowth was evidenced by TEM, and its formation may be ascribed to the competition between ZSM-11 and ZSM-5 zeolite in the system. The morphology of zeolite varies with the change of composition of the starting gel. The a+/SiO2 ratios. With the increase the O H −/ particle sizes of the products decrease with the increase of 1,3-CDA/SiO2 and N SiO2 ratio, the sizes decrease at first and then increase. Meanwhile, the morphologies change from cross-like aggregates of orthotropic rods to aggregates of nano-rods, and then to irregular bulk crystals. With the decrease of S iO2/Al2O3 ratios from 100 to 40, the particle sizes decrease from 200 to about 50 nm, resulting in the formation of nanosized ZSM-11/ZSM-5 intergrowth zeolite. Keywords ZSM-11 · ZSM-5 · Intergrowth zeolite · 1,3-Cyclohexanedimethanamine · Morphology
1 Introduction Zeolites are important microporous crystalline materials and have been found applicable in a wide range of areas, such as catalysis, adsorption, separation, and ion-exchange [1]. Since the pioneering work by Barrer in the early 1960s [2], numerous organic compounds, usually known as the structure-directing agents (SDAs) or organic templates, have been extensively used for the synthesis of novel zeolites and related microporous materials [3, 4]. Up to now, it is still the most important and effective way to obtain materials with new pore structures, morphologies and/or properties. Recently, research on the preparation of intergrowth zeolites has drawn much attention, because the combination of two structural phases may offer possibilities to obtain better * Zhendong Wang [email protected] * Weimin Yang [email protected] 1
State Key Laboratory of Green Chemical Engineering and Industrial Catalysis, Sinopec Shanghai Research Institute of Petrochemical Technology, Shanghai 201208, China
adsorbents and catalysts [5–7]. Seeking for the special properties of those materials has motivated the discovery of a series of zeolites with intergrowth structures, such as zeolite beta [8], MTT/TON [9], EMT/FAU [10], RTH/ITE [11], CHA/AEI [12], and ERI/OFF [13]. A multitude of studies have illustrated that the precondition for the formation of these zeolitic materials is that the intergrown frameworks should have at least part of or all of the basic structure building units in common [14]. ZSM-5 (MFI) and ZSM-11 (MEL) zeolites are very important members of the pentasil
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