催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (7): 788-792.

• 研究论文 • 上一篇    下一篇

ZSM-35 分子筛的静态合成和晶化机理

鞠晓花1,2, 范峰滔2, 田福平1, 冯兆池2   

  1. 1 大连理工大学化工学院化学系精细化工国家重点实验室, 辽宁大连 116024 2 中国科学院大连化学物理研究所催化基础国家重点实验室, 辽宁大连 116023
  • 收稿日期:2010-07-25 出版日期:2010-07-25 发布日期:2010-07-25

Static Synthesis and Crystallization Mechanism of ZSM-35 Zeolite

JU Xiaohua1,2, FAN Fengtao2, TIAN Fuping1,*, FENG Zhaochi2,*   

  1. 1State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China 2State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2010-07-25 Online:2010-07-25 Published:2010-07-25

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1562

被引次数

6

摘要： 以环己胺为有机模板剂, 硅溶胶为硅源, 采用静态合成法在 220 ºC 的水热体系中制得了 ZSM-35 分子筛纯相. 当初始凝胶中含有一定量的 K+时, 在晶化过程中, K+与Na+的共同作用可以很好地抑制混晶丝光沸石的生成, 且当 n(K+)/n(K+ + Na+) = 0.3 时, 制得的 ZSM-35 分子筛晶化度最高. 利用 X 射线衍射和紫外拉曼光谱对分子筛形成的最佳条件以及晶化机理进行了研究. 发现合成初期前体中含有五元环和六元环的硅物种构筑单元. 通过水热晶化过程, 与硅酸盐的五元环或六元环有关的 450 cm–1 处紫外拉曼谱峰增强, 在晶化后期, 随着无定形凝胶逐渐被消耗, 在 421, 312 和 215 cm–1 处出现新的 ZSM-35 结构的特征拉曼谱峰, 说明这些环物种相互聚集最终形成了 ZSM-35 分子筛.

关键词: ZSM-35 分子筛, 静态合成, 环己胺, 晶化机理

Abstract: The pure ZSM-35 zeolite was synthesized in a static hydrothermal system at 220 ºC using cyclohexylamine as the template and silica sol as the Si source. When the initial gel contained a certain amount of K+, the mutual role of K+ and Na+ inhibited the formation of mordenite, and well crystallized product was formed with n(K+)/n(K++Na+) = 0.3. Optimum regions of the synthetic conditions of ZSM-35 zeolite obtained by X-ray diffraction were n(M2O)/n(Al2O3) = 3.2–3.4 and n(SiO2)/n(Al2O3) = 22. The building units in the precursor were identified as five-membered and six-membered silicate rings by UV-Raman spectroscopy. The intensity of the Raman band at 450 cm–1 increased in the beginning of crystallization, and the new bands at 421, 312, and 215 cm–1 appeared with consuming the amorphous gel, indicating that the ring species were turned out to be aggregate through the hydrothermal treatment, and finally formed ZSM-35 zeolite. The strong Raman band at 421 cm–1 should be assigned to the bending vibration of the five-membered silicate ring, and the Raman band at 312 cm–1 might cor-respond to the six-membered silicate ring of ZSM-35 zeolite framework.

Key words: ZSM-35 zeolite, static synthesis, cyclohexylamine, crystallization mechanism