Journal of Petrochemical Universities

Journal of Petrochemical Universities ›› 2013, Vol. 26 ›› Issue (4): 21-26.DOI: 10.3969/j.issn.1006396X.2013.04.005

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Synthesis of Pure ZSM22 Zeolites via Suppressing Intergrowths of Competing Phases

  

  1. (1. School of Chemical and Materials Science,Liaoning Shihua University, Fushun Liaoning 113001,China;  2. School of Petrochemical Engineering, Liaoning Shihua University, Fushun Liaoning 113001,China)
  • Received:2013-02-01 Published:2013-08-25 Online:2013-08-25

ZSM-22沸石合成与共生竞争相控制

孙月桥1,张圆圆1,杜夏梅1,金英杰2   

  1. (1.辽宁石油化工大学化学与材料科学学院,辽宁抚顺113001;2.辽宁石油化工大学石油化工学院,辽宁抚顺113001)
  • 作者简介:孙月桥(1986-),女,河北邯郸市,在读硕士。
  • 基金资助:
    辽宁省自然科学基金资助项目(200922180)。

Abstract: The effect of hydrothermal synthesis conditions on both relative crystallinity and phase purity of ZSM22 zeolites was investigated in SiO2Al2O3K2ODAHH2O system, hereby DAH referring to 1,6diaminohexane as template. The resulting samples were characterized by powder Xray diffraction (XRD) and inductively coupled plasma (ICP) analyses in order to examine the structure, XRD phase, and chemical composition. As a result, several ZSM22 zeolites with the higher phase purity were synthesized at respective temperatures from 433 K up to 438 K by use of the different gels which involved SiO2/Al2O3 molar ratios of 80~100 and OH-/SiO2 molar ratios of 0.33~0.35. It is found that the relative crystallinity and phase purity of ZSM22 zeolites markedly varied as a function of crystallization temperature, SiO2/Al2O3 and OH-/SiO2 molar ratios. In fact, an adequate increase in crystallization temperature improves on ZSM22 phase purity, followed a significant enhancement of relative crystallinity. Although the ZSM5 crystal growth takes place predominantly in the solid phase, the decrease in the range of SiO2/Al2O3 ratio less than 80 leads to a gradual increase in the ZSM5 phase fraction while the increase in SiO2/Al2O3 ratio larger than 110 also enhances the phase fraction of cristobalite. Furthermore, Si/Al atomic ratios in ZSM22 framework located the range of 41.8~53.4, and by correlating the Si/Al ratio of ZSM22 framework with the SiO2/Al2O3 ratio of aluminosilicate gels, it is noted that the nominal ratios in ZSM22 framework tended to shift towards the center of the Si/Al ratio interval mentioned above.

Key words: Zeolite synthesis,    , ZSM22,    ,  Competing phase,   ,  ZSM5,    , Cristobalite,    ,  Relative crystallinity,   ,  Phase purity

摘要: 在SiO2Al2O3K2ODAHH2O(1,6己二胺,DAH)体系中,研究水热合成条件对ZSM22沸石相对结晶度和相纯度的影响。采用X射线衍射(XRD)和电感耦合等离子体(ICP)技术表征合成产物的结构、物相及化学组成。结果表明,合成胶n(SiO2)/n(Al2O3) 在 80~110,n(OH-)/n(SiO2) 在 0.33~0.35和433~438 K条件下,合成出系列相纯度较高的ZSM22沸石。产物相对晶度和相纯度依赖于合成胶硅铝物质的量比、碱度和晶化温度。适当升高晶化温度有利于提高产物的相纯度和相对结晶度;n(SiO2)/n(Al2O3)在80~110之外,合成胶硅铝物质的量比的降低或提高分别导致ZSM5或方石英相分率的逐渐增加。此外,纯ZSM22骨架n(Si)/n(Al)分布于41.8~53.4;与n(SiO2)/n(Al2O3)关联可知,n(Si)/n(Al)比值向该区间中心呈收敛趋势。

关键词: 沸石合成 , ZSM-22 竞争相 , ZSM-5 , 方石英 , 相对结晶度 , 相纯度

Cite this article

SUN Yueqiao,ZHANG Yuanyuan,DU Xiamei,et al. Synthesis of Pure ZSM22 Zeolites via Suppressing Intergrowths of Competing Phases[J]. Journal of Petrochemical Universities, 2013, 26(4): 21-26.

孙月桥,张圆圆,杜夏梅,金英杰. ZSM-22沸石合成与共生竞争相控制[J]. 石油化工高等学校学报, 2013, 26(4): 21-26.