A Study on Synthesis of Silicates by High-Pressure Hydrothermal Method using Organic Template Reagents

研究了压力条件和有机离子对高压水热法制备的硅酸盐形貌的影响。并以具有良好发光性能的稀土离子为探针，研究了沸石微孔的物理化学环境特征：(1)有机模板离子对沸石形貌的影响合成了一系列组成公式为R_3R‘n^+X^-(R=R’)的不对称四烷基铵盐，并将其用于制备五元系ZSM-5沸石。所得沸石的组成和形貌与ZSM-5沸石有很大的不同。沸石微孔的物理化学环境与Eu~(2+)、Lt；~(3+)和Gt~(2+)离子交换的沸石分子筛表现出基于f-f跃迁的红色发射带，这种发光性质可以通过引入有机配体2，2‘-联吡啶、2，6-吡啶甲酸和乙酰丙酮来修饰。特别是，发光强度显著提高。根据发光图谱，讨论了分子筛中Eu~(2+)~(3+)~(2+)的对称性。

This study was carried out on the influences of pressure conditions and organic ions on the morphology of the silicates prepared by high-pressure hydrothermal method. Also, the physicochemical environmental characteristics of the micropores of zeolites were investigated by using the rare earth ion with excellent luminescence properties as a probe.(1) Influence of the organic template ions on the morphology of resulting zeolitesA series of unsymmetrical tetraalkyl ammonium salts with the composition formula of R_3R'N^+X^- (R=R') were synthesized and were used to prepare the pentasil-type ZSM-5 zeolite. The composition and morphology of the zeolites obtained by using them were considerably different from those of ZSM-5 zeolite. This indicates that the unsymmetrical ammonium salts possess a possibility for the formation of new zeolites.(2) Physicochemical environment of the micropores of zeolitesThe zeolites ion-exchanged with Eu^<3+> ions showed a red emission bands based on the f-f transition, and this luminescence properties were modified by introductions of organic ligands such as 2, 2' -bipyridene, 2, 6-pyridinecarboxylic acid, and acetylacetone. Particularly, the luminescence intensity was considerably increased. The symmetry around the Eu^<3+> ion in zeolites was discussed on the basis of the luminescence patterns.