超疏水性有机无机杂化层状钛硅亚微球的合成及其催化烯烃环氧化反应性能研究

Titanium-containing zeolites and related materials have been found to be effective for the selective oxidation of organic compounds with aqueous hydrogen peroxide. Isolated tetrahedrally-coordinated Ti4+ and its location in a hydrophobic environment is the key for high catalytic activity. In this project, we propose to synthesize an organic-inorganic hybrid layered titanosilicate submicrosphere with superhydrophobicity, high surface area and well dispersed catalytic active center. The strategy of synthesis of this superhydrophobic layered titanosilicate sub-sphere is based on an arosol-assisted self-assemble (AASA) process by using alkytriethoxysilanes and alkyl orthotitanates as precursors without adding any organic template. The structure, morphology and hydrophobicity of the synthesized materials will be tuned by controlling the sol-gel process and evaporation-induced assembly procedure. This project will focus on the self-assemble mechanism of superhydrophobic layered titanosilicate. Furthermore, the catalytic activity of the resultant materials will be assayed in olefins epoxidation at room temperature. After establishing the structure-activity relationships, the catalytic mechanism of spuerhydrophobic titanosilicate materials in olefins epoxidation will be further investigated. This superhydrophobic organic-inorganic hybrid layered titanosilcate sub-sphere with excellent catalytic activity and selectivity will be a promising catalyst for selective oxidation of olefins using H2O2 aqueous. It is also expected to provide new opportunities for applying superhydrophobic materials in industry catalytic fields.

钛硅分子筛类材料是一类以过氧化氢为氧化剂的有机物选择性氧化反应的有效催化剂，独立分散的四配位钛和高疏水性的微观环境是获得高效催化活性的关键。本项目提出合成一种超疏水性、高比表面积且催化活性中心高度分散的有机无机杂化的层状钛硅亚微球材料。以有机硅氧烷基和钛的醇盐为共同前驱体，采用气溶胶辅助自组装的方法（Arosol-Assisted Self-Assembly, AASA）使有机、无机分子在三维限制空间内自组装成超疏水性钛硅亚微球结构，通过控制溶胶-凝胶过程和挥发诱导自组装的方式来调控材料的结构、形貌以及疏水性能；重点研究超疏水层状钛硅亚微球的形成过程；研究超疏水层状钛硅材料室温下对环己烯环氧化的催化活性和催化机理，探究超疏水材料的结构与催化活性的构效关系；在此基础上针对烯烃环氧化反应设计合成出低能耗、高效率、高稳定性的选择性氧化催化剂，为拓展超疏水材料在催化领域的应用提供可行的途径。

钛硅分子筛材料是一类以过氧化氢为氧化剂的有机物选择性氧化反应的有效催化剂，其在有机物选择性氧化催化反应的活性除了与催化活性中心钛的配位形式及分散状态有关外，还与催化剂表面的亲/疏水性能有关，而且越来越多的研究表明钛硅材料的亲/疏水性能是影响催化活性的至关重要的因素。独立分散的四配位钛和高疏水性的微观环境是获得高效催化活性的关键。本项目提出合成一种超疏水性且催化活性中心高度分散的有机无机杂化的层状钛硅亚材料。经过为期四年的研究，取得了以下研究成果：（1）以苯基三甲氧基硅烷和钛酸丁酯为前驱体，采用挥发诱导自组装的方法，合成得到超疏水性有机无机杂化的层状钛硅材料，该材料在室温下的烯烃环氧化反应中表现出优异的催化性能。（2）采用气溶胶辅助自组装（Aerosol-Assisted Self-Assembly，AASA）的方法，使有机、无机分子自组装成钛硅微球材料（micro-sphere layered organo-titanosilicate，简称ms-LOTS），室温下催化环己烯环氧化反应中的活性是工业TS-1的15倍。（3）以二氧化硅亚微球为硬模板，将超疏水的层状钛硅材料LOTS负载到二氧化硅亚微球材料的表面，制备得尺寸为104 nm左右的超疏水性钛硅亚微球材料，其催化活性是工业TS-1的60倍。（4）以介孔的EP-FDU-12为硬模版，采用AcHE方法合成具有超大孔的EP-FDU-WZrOx固体酸，该固体酸具有耐水热稳定（300oC的水热）和耐高温（1000oC）的性能，并且有机污染物的催化降解反应表现优良性能。