Abstract:

With the implementation of green chemical industry strategy, titanium silicalite has attracted widespread attentions due to its unique selective epoxidation ability. Therefore, the rational structure regulation of titanium silicalite is the key to enhance the olefin epoxidation. This paper systematically summarized the synthesis strategies of high-performance titanium silicalite by adjusting the structure type, the molar ratio between Si and Ti atoms, the surface hydrophobicity and the mass transfer in particles, and the industrial process of TS-1 was introduced. Moreover, using the metal-loaded titanium silicalite as the example, we highlighted the reaction performance and mechanism of propene epoxidation with H₂ and O₂, and affirmed the importance of the titanium and the metal dual sites in the catalyst. Among them, the efficiency of metal sites could be tuned from three aspects of electrical property, size effect and space distribution, as illustrated based on the Au-based catalysts. Moreover, based on the current problems and challenges of propene epoxidation with H₂ and O₂, potential solutions and future directions were further proposed.

Key words: titanium silicalite, propene epoxidation, metal site, molecular sieves, catalyst, chemical reaction

摘要：

随着绿色化工发展战略的推进，钛硅分子筛凭借其独特的选择性环氧化能力而引起广泛关注，合理调控钛硅分子筛的结构是提升烯烃环氧化反应效果的关键。本文分别对钛硅分子筛的结构类型、硅钛原子比、表面疏水性、颗粒传质性能的调控方法进行了介绍，系统总结了高活性钛硅分子筛的合成策略，并概述了TS-1钛硅分子筛工业生产技术的进展。以负载金属的钛硅分子筛催化剂为例，着重讨论了基于该催化剂的丙烯直接临氢气相环氧化反应的性能与机理，肯定了催化剂中包括载体钛位点和负载金属位点的双位点在环氧化反应中的重要性，并从金基催化剂的电子性质、空间分布、尺寸效应三个方面总结了高效金属位点的调控策略。此外，基于丙烯气相临氢环氧化当前存在的问题与挑战，进一步提出其潜在的解决方案与未来的发展方向。

关键词: 钛硅分子筛, 丙烯环氧化, 金属位点, 分子筛, 催化剂, 化学反应