Facile Synthesis and Catalysis of Pure-Silica and Heteroatom LTA
Facile Synthesis and Catalysis of Pure-Silica and Heteroatom LTA
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DOI：
10.1021/acs.chemmater.5b03579
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发表时间：
2015-11-24
影响因子：
8.6
通讯作者：
Davis, Mark E.
中科院分区：
文献类型：
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作者：
Boal, Ben W.;Schmidt, Joel E.;Davis, Mark E.
A型沸石(LTA)在分离和离子交换方面有许多大规模的用途。由于铝含量高，高温稳定性差，在催化方面的应用受到极大的限制。在此，我们报道了一种在氟化物介质中用一种简单的咪唑基有机结构导向剂制备纯二氧化硅、铝硅酸盐(产物Si/Al=12-42)和钛硅酸盐LTA的可靠方法。铝硅酸盐材料是甲醇制烯烃反应的活性催化剂，与商品化的具有沸石骨架的硅铝磷酸盐或沸石类似物(分别为SAPO-34和SSZ-13)相比，对丁烯以及C-5和C-6产物具有更高的产物选择性。用单晶X射线衍射法测定了纯二氧化硅材料的晶体结构，提供了被封闭的有机物和氟化物的信息以及结构信息。
AZeolite A (LTA) has many large-scale uses in separations and ion exchange applications. Because of the high aluminum content and lack of high-temperature stability, applications in catalysis, while highly desired, have been extremely limited. Herein, we report a robust method to prepare pure-silica, aluminosilicate (product Si/Al = 12-42), and titanosilicate LTA in fluoride media using a simple, imidazolium-based organic structure-directing agent. The aluminosilicate material is an active catalyst for the methanol-to-olefins reaction with higher product selectivities to butenes as well as C-5 and C-6 products than the commercialized silicoalumniophosphate or zeolite analogue that both have the chabazite framework (SAPO-34 and SSZ-13, respectively). The crystal structures of the as-made and calcined pure-silica materials were solved using single-crystal X-ray diffraction, providing information about the occluded organics and fluoride as well as structural information.