论文部分内容阅读
从宏观和微观角度简要总结了微孔晶体晶化过程及晶化机理的研究,包括微孔晶体的成核与晶体生长(宏观角度)、晶化机理的主要观点、结构导向效应、研究微孔晶体晶化的主要技术手段及最新的研究思路和策略(微观角度).借鉴于致密晶体晶化行为的研究,微孔晶体的晶化过程分为成核与晶体生长两个阶段.在成核阶段,提出了晶核可以从液相(液相成核)、固相(固相成核)或固液相(双相成核)中成核,后被统一为“通用”成核机制.在晶体生长阶段,研究主要集中于生长模式.受制于当前较低分辨率和灵敏度的表征手段以及合成体系的复杂度,人们对晶体的成核与生长机制的认识还存在着极大的争议.在微孔晶体的晶化过程及晶化机理研究中,一项重要的内容是通过特定的表征手段确认在晶化过程中生成的小结构单元,包括色谱、电喷雾质谱、原位和非原位核磁共振、紫外拉曼光谱等.结合实验数据和理论计算可以确定一些单靠实验数据不能确认的结构单元.在微孔晶体的晶化过程中,结构导向剂起到了极其关键的作用.本文简要总结了结构导向剂的种类和导向的典型结构.最后介绍了新近提出的“反向进化”法,该方法可用于研究在晶化的早期阶段生成的小结构单元及晶化起点的结构.
From the macroscopic and microscopic perspectives, the crystallization process and crystallization mechanism of microporous crystals are briefly summarized, including the nucleation and crystal growth of microporous crystals (macroscopic perspective), the main viewpoints of crystallization mechanism, structure-oriented effect, micropore Crystallization of the main technical means and the latest research ideas and tactics (microscopic point of view) .Based on the study of the crystallization behavior of dense crystals, the crystallization process of microporous crystals into nucleation and crystal growth in two stages.In the nucleation Stage, it is proposed that the nuclei can nucleate from the liquid phase (liquid phase nucleation), the solid phase (solid phase nucleation) or the solid-liquid phase (biphasic nucleation) and be unified as “common” nucleation Mechanism.At the stage of crystal growth, the research mainly focuses on the growth mode.Because of the current low resolution and sensitivity characterization methods and the complexity of the synthesis system, there is still a great understanding of the nucleation and growth mechanism of the crystal Controversy.In the study of crystallization process and crystallization mechanism of microporous crystals, an important content is to identify the small structural units generated in the crystallization process by specific characterization methods, including chromatography, electrospray ionization mass spectrometry, in situ and Non-nuclear magnetic resonance, External Raman spectroscopy, etc. Combining the experimental data and theoretical calculations, it is possible to determine some structural units that can not be confirmed solely by experimental data. In the crystallization of microporous crystals, the structure-directing agent plays an extremely crucial role.In this paper, Finally, we introduce the newly proposed “reverse evolution ” method, which can be used to study the structure of the small structural units and the starting point of crystallization in the early stage of crystallization.