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

研究了高压水热法合成硅酸盐的压力条件和有机离子对硅酸盐形貌的影响。并以具有优异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性。(1)有机模板剂离子对ZSM-5分子筛形貌的影响合成了一系列组成式为R_3R 'N ^+X^-（R= R'）的不对称四烷基铵盐，并将其用于合成pentasil型ZSM-5分子筛。用它们制得的分子筛的组成和形貌与ZSM-5分子筛有很大的不同。这表明不对称铵盐具有形成新型沸石的可能性。(2)分子筛微孔的物理化学环境Eu^<3+>离子交换后的分子筛显示出基于f-f跃迁的红色发光带，并通过引入有机配体如2，2' -联吡啶、2，6-吡啶甲酸和乙酰丙酮对这种发光性质进行了修饰。特别地，发光强度显著增加。根据发光模式讨论了分子筛中Eu^<3+>离子周围的对称性。

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.