规整中孔TiO2微球的均相沉淀合成及其在环戊烯氧化反应中的应用

TiO2作为重要的功能性环保无机材料, 因具有特殊的光电性质和物化性能而广泛应用于介(压)电材料、涂料及催化等领域1～3]. 戊二醛(Glutaraldehyde)是一种重要的精细化学品, 但其生产工艺复杂、条件苛刻. 邓景发等4]成功开发了以环戊烯为原料, 双氧水为氧化剂, 均相钨酸为催化剂的新型一步法合成路线, 工艺操作简单, 降低了生产成本. 但由于均相催化剂分离复杂, 其固载化方法正在研究中5～7]. 本文以TiCl4为前驱体, 在均相醇-水热体系中首次合成了高比表面积和规整中孔结构的TiO2微球(约3.6 μm), 其外壳约100 nm, 空隙壳层约300 nm. 考察了制备条件对TiO2微球结构的影响, 并采用孔分布, XRD, SEM及TEM等手段对该TiO2微球进行了表征, 同时考察了TiO2微球负载的WO3催化剂在环戊烯催化氧化合成戊二醛中的反应行为, 并与其它载体进行了比较.

Preparation of Core-shell Titania Spheroid with Mesoporous Structure and the Application in Synthesis of Glutaraldehyde

A novel process for preparation of micrometer-scale functional materials without organic templates has been demonstrated. Titania spheroid with a tailored core-shell structure and high ordered mesoposity has been manipulated in the ethanol hydrothermal system containing ammonia sulfate as a dispersant. Titania spheroid with a mean diameter of 3.6 μm and a high specific surface area of 266 m2/g has been synthesized by precipitating titanium tetrachloride with ammonia gas released from hydrolysis of urea at a high temperature. A special core-shell structure with a 100 nm thin shell and a 300 nm spacing strip interiors has been characterized by SEM &; TEM. The catalytic performance of the titania spheoid supported WO3 catalyst for the selective oxidation of cyclopentene(CPE) to glutaraldehyde(GA) has been investigated. The WO 3/TiO2 spheroid catalyst displays an exciting prospect for good selectivity(72.9%) toward GA and a high GA yield(about 70%) for the titled reaction using aqueous H2O2 as the oxidant.