沸石分子筛的生成机理和晶体生长(Ⅱ)——电子衍射法研究液相中分子筛晶核的生成

THE MECHANISM OF FORMATION AND CRYSTAL GROWTH OF MOLECULAR-SIEVE-ZEOLITE-Ⅱ-THE STUDY ON NUCLEATION OF MOLECULAR-SIEVE-ZEOLITE IN A LIQUID PHASE BY THE ELECTRON DIFFRACTION METHOD

研究沸石分子筛生成机理与晶体生长中的一个重要关键问题是沸石分子筛的晶核如何形成。核的形成条件、结构和互变性能直接影响分子筛的生成、晶体生长以及杂晶的存在与消除,是目前国际上分子筛化学界关注的问题之一。然而直到目前为止尚缺乏直接而有效的研究方法。我们曾经应用固体宽谱Na23-核磁共振法研究过八面沸石结构导向剂溶胶与凝胶固相中晶核的生成问题,在晶核较大时可以得到较满意的结果。

The study on nucleation of molecular-Sieve-Zeolite is an important key to the investigation of the mechanism of formation and crystal growth of Molecular-Sieve-Zeolite.This is one of the problems to which Zeolite-Chemists pay close attention.But there is no efficient method so far.We applied broad line Na23-NMR technique to investigate the existence and growth of nucleation center with Faujasite type structure in a colloidal system and obtained some satisfactory results if sizes of the nuclei were bigger.To look for new research means,we made use of electron diffraction method to detect and study the nuclei in a sol of aluminosilicates.An example was introduced here.It is proved that there are nuclei of NaX type Zeolites in a sol of Faujasite type"Directing-Agent"which ages in a short time.So the application of the electron diffraction method to investigate the nucleation of Zeolite in a liquid phase seems to be a new development.