含氟钛硅分子筛的结构特征及其催化性能研究

项目名称： 含氟钛硅分子筛的结构特征及其催化性能研究

项目编号： No.21503154

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 方向青

作者单位： 西安航空学院

项目金额： 21万元

中文摘要： 目前关于钛硅分子筛/H2O2体系中会形成Ti-O-O-H活性中间体，已经得到共识，在环氧化反应体系中碳碳双键会优先与电负性更强的氧原子结合实现氧的传递。本项目从增强分子筛Ti活性中心的正电性角度出发，将具有强拉电子效应的氟元素植入分子筛骨架，得到一系列含氟的钛硅分子筛。通过一系列物理化学表征手段，对分子筛中氟的具体存在形式进行解析，结合分子筛本身的物化性质变化，揭示F植入钛硅分子筛骨架的反应历程。并对含氟系列的钛硅分子筛进行催化氧化性能表征，进一步明确氟的结构单元与钛硅分子筛催化氧化性能之间的关系。通过对比分子筛两种不同的氟结构单元(SiO3/2F和SiO4/2F-)的结构特性及其催化性能特征，进一步采用后处理的方式，选择性的去除分子筛中SiO4/2F-基团的负面作用，进一步提高分子筛的催化性能，为实现高性能含氟钛硅分子筛的可控设计与合成提供新思路。

中文关键词： 含氟钛硅分子筛；后处理改性；氟核磁；催化氧化性能；形成机理

英文摘要： It is fairly well accepted that the Ti-O-O-H which is generated by the interaction of the Ti (IV) framework, in the case of epoxidation, the C=C double bond in alkenes is expected to interact with more electrophilic O as the active oxygen-donating species. Implant fluorine species into titanosilicates will influence its catalytic property through change the electronegativity of these two oxygen atoms. In this project, we focus on synthesis a series of fluorine-planted titanosilicates through an post-synthesis in the presence of fluoride, multiple characterization measurements will be carried out comprehensively to reveal the formation mechanism of SiO3/2F units. Furthermore, we will compare the catalytic oxidation performance of fluorine-planted titanosilicates which have different fluorine species, clarify the relationship of the structure and property. In addition, the adverse effect of F- can be eliminated by the synergistic effect between anion and cation in the inorganic salt. Inorganic salt post-treatment process basically has following two effects: anion can availably exchange part of the F- in the F-Ti-MWW zeolite, meanwhile, the metal cation itself has strong electropositive which could neutralize the electronegative of residual F-, the catalytic performance of F-Ti-MWW will be further enhanced. This work will provide a new idea of design and synthesis of fluorine-planted titanosilicates with excellent catalytic activity.

英文关键词： Fluorine-planted Titanosilicate;Post-synthesis Modifiction;19F MAS NMR;Catalytic Oxidation Activity;Formation Mechanism