高等学校化学学报

高等学校化学学报 ›› 2000, Vol. 21 ›› Issue (8): 1161.

• 论文 •    下一篇

四乙基溴化铵-氟化物复合模板剂合成β沸石(Ⅱ)──β沸石晶化过程研究

祁晓岚1, 刘希尧1, 陈钢1, 陈学艺1, 李士杰2, 林炳雄2   

  1. 1. 燕山石化集团公司研究院, 北京 102500;
    2. 北京大学物理化学研究所, 北京 100871
  • 收稿日期:1999-09-09 出版日期:2000-08-24 发布日期:2000-08-24
  • 通讯作者: 刘希尧(1936年生),男,教授级高级工程师,博士生导师,主要从事沸石分子筛合成、表征及石油化工与精细化工应用研究.

Synthesis of β Zeolite Using Tetraethylammonium Brom ide Together with Fluoride as Composite of Template(Ⅱ) ── Studies on Crystallization Process of β Zeolite

QI Xiao-Lan1, LIU Xi-Yao1, CHEN Gang1, CHEN Xue-Yi1, LI Shi-Jie2, LIN Bing-Xiong2   

  1. 1. Research Institute of Yanshan Petrochemical Corporation, Beijing 102500, China;
    2. Institute of Physical Chemistry, Peking University, Beijing 100871, China
  • Received:1999-09-09 Online:2000-08-24 Published:2000-08-24

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摘要： 采用FT-IR,XRD,SEM,TG,ICP-AES等技术研究了四乙基溴化铵(TEABr)-氟化物复合模板剂体系合成β沸石的晶化过程.发现本体系β沸石的合成遵循液相转变机理,在诱导期向生长期转变的转折点存在过渡态,氟离子对过渡态的形成和转变起到重要作用.在诱导期初期固相是富铝的,但晶体生长期固相硅铝比基本不变,表明硅铝同步进入骨架.

关键词: &beta, 沸石, 晶化过程, 复合模板剂, 过渡态, 氟离子

Abstract: The crystallization process of β zeolite has been investigated by using FT IR, XRD, TG, SEM, and ICP AES. The samples were obtained by hydrothermal synthesis at 140 ℃ and chemical composition of the mixture used for synthesis can be expressed as n(Al2O3)∶n(SiO2)∶n(TEABr)∶n(Na2O)∶ n(NaF) ∶n(H2O)∶n =1∶25∶7.5∶2.5∶3.75∶550∶6.25. The crystallization curve of zeolite β exhibits a typical Sshaped characteristic. The typical framework IRabsorptions at 567 and 518 cm-1 have different natures. The former is detected at the beginning of induction period and its intensity changes a little in induction period, but exhibits a direct correlation with crystallinity in growth period. The latter is not detected in the induction period, but exhibits the same trend in growth period. The large amorphous SiO2 Al2O3 particles which are visible at the beginning of crystallization change into small grains during the induction period. n(SiO2)/n(Al2O3) ratio of the solid phases obtained at different synthesis time changes significantly during the induction period, but changes a little in growth period. So the β zeolite crystal nucleus are formed via liquid phase synthesis mechanism. Atypical gel in synthesis of β zeolite is transformed initially into a solid, which contains richer aluminium, minor F- and occluded TEAspecies. The aluminosilicate gel particles are dissolved by F- during the induction period and the transition complex, which has a specific weak X-ray diffraction peak at 2θ=22.8° and specific DTGpattern, is formed at the turning point from induction period to growth period. During the growth period Si and Al transport from the liquid to the solid phase at almost the same rates. F- anion has greater influence on the formation and turning of transition complex.

Key words: Zeolite, Crystallization process, Composite of template, Transition state, Fluorine anion

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