非水热法Bi／MSU-2的合成及其催化氧化性能  

SYNTHESIS AND CATALYTIC OXIDATION ACTIVITY OF Bi/MSU-2 BY NON-HYDROTHERMAL METHOD

作　　者：许锦鹏[1] 陈晓晖[1] 魏可镁[1] 

机构地区：[1]福州大学化肥催化剂国家工程研究中心,福建福州350002

出　　处：《石油学报（石油加工）》2006年第B10期235-237,共3页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：国家自然科学基金（20306004）资助项目

摘　　要：以非离子表面活性剂辛基酚聚氧乙烯醚（TX-100）为模板剂，正硅酸乙酯为硅源，在室温酸性条件下（pH-2），采用水解缩聚法一步合成纯硅MSU-2型中孔分子筛。采用离子扩散法、等体积浸渍法、物理机械混合法制备了3种含铋（Bi）的MSU-2样品，并通过XRD、UV-Vis等表征手段研究了分子筛的孔道、骨架结构等物相结构，并考察了它们对苯乙烯的催化氧化反应性能。结果表明，所合成的样品均具有MSU—x典型的三维无序、孔径均一的中孔结构，Bi原子进入分子筛骨架并高度分散于骨架中。以H2O2为氧化剂，甲醇为介质，苯乙烯催化氧化制苯甲醛的反应中，采用浸渍法得到的Bi／MSO-2分子筛样品活性最低；离子扩散法的效果最好，苯乙烯转化率达到34．1％，苯甲醛产率高达22．3％。这可能是由于Bi元素迁移到分子筛孔道中，在内表面上有很好的分散性，而且形成某种特殊的有助于催化氧化的活性中心。由离子扩散法制备的分子筛样品中活性中心的有效含量高于由其他方法制备的Bi／MSU-2。Novel pure silica mesoporous MSU-2 molecular sieve was synthesized using Triton X100 as a neutral surfactant template, tetraethylorthosilicate （TEOS） as a silica source, followed by removing the pore-forming agent by calcinations. Then, three samples doped with Bi were prepared by different methods （ionmigration, impregnation, physically mixing）. Characterization results from X-ray diffraction （XRD） and Ultraviolet visible diffuse reflectance spectroscopy （UV-Vis） indicated that all the samples possessed non-ordered wormhole-like pore structures with no long-range symmetry and the incorporation of Bi^3＋ into the zeolit~ framework, and Bi atoms were highly dispersed in the silica-based structure of MSU-2. Catalytic activity evaluation of the materials in the oxidation of styrene to benzaldehyde with H2 02 in the methanol medium was also reported. It was found that the catalyst prepared through ion-migration had the best activity due to the better dispersion of Bi on the inner surface of MSU-2 and formation of more special structure, which showed more catalytic activity than those prepared by other methods.

关 键 词：Bi/MSU-2 离子扩散 浸渍 物理混合 非水热法 苯甲醛 

分 类 号：O643.3[理学—物理化学] TQ426[理学—化学]