以丁二酸-氯化胆碱-四乙基溴化铵三元低共熔混合物作为溶剂和模板剂,借助微波辐射在常压下合成了具有多级孔结构的 SAPO-5分子筛。系统地考察了 P2O5/Al2O3与 HF/Al2O3摩尔比,硅源与晶化时间等条件对多级孔SAPO-5分子筛合成的影响。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、N2物理吸脱附以及29Si魔角旋转核磁共振(29Si MAS-NMR)等手段对合成产物的结构和性质进行了表征。分析结果表明：在 SAPO-5分子筛晶体中同时存在晶体内介孔和晶体间介孔,29Si MAS-NMR分析表明Si的取代方式以SM3取代机理为主。此外,通过SEM可知在特定合成条件下可得到具有六角纳米盘状特殊形貌的多级孔SAPO-5分子筛。
Hierarchical structured SAPO-5 molecular sieve was ionothermally synthesized by microwave irra-diation using a mixture solution of succinic acid, choline chloride and tetraethyl ammonium bromide as solvent and template under ambient pressure. The effects of the molar ratios of P2O5/Al2O3 and HF/Al2O3, silicon source, and crystallization time on the structure of SAPO-5 molecular sieve were systematically investigated. The re-sulting SAPO-5 molecular sieve was characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), N2 physical adsorption-desorption and 29Si magic-angle spin-ning nuclear magnetic resonance (29Si MAS-NMR) techniques, respectively. The results indicate that in-tra-crystalline and inter-crystalline mesopores coexist within the SAPO-5 molecular crystals, while 29Si MAS-NMR test shows that the incorporation of Si in the sample follows the SM3 mechanism. In addition, SEM images exhibit that hierarchical structured SAPO-5 molecular sieve with hexagonal nanometer-disc morphology can be synthesized under specific synthetic conditions.
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