硅烷化对Ti/HMS分子筛催化性能的影响  

Influence of Silylation on Catalytic Performance of Ti/HMS Molecular Sieve

作　　者：李学峰[1] 高焕新[2] 金国杰[2] 丁琳[2] 陈璐[2] 杨洪云[2] 何欣[2] 陈庆龄[1] 

机构地区：[1]华东理工大学化学与分子工程学院,上海200237 [2]中国石化上海石油化工研究院,上海201208

出　　处：《催化学报》2007年第6期551-556,共6页

基　　金：国家重点基础研究发展规划(973计划;2003CB615805).

摘　　要：分别用水热法和气相沉积法制备了Ti/HMS分子筛,采用三甲基氯硅烷(TMCS)和六甲基二硅氮烷(HMDSZ)对Ti/HMS样品进行了气相硅烷化,并用X射线衍射、N2吸附、红外光谱、29Si核磁共振和紫外-可见光谱对样品进行了表征.丙烯环氧化反应的测定结果表明,硅烷化可显著提高环氧化催化活性.水热法制备的Ti/HMS经HMDSZ硅烷化后的催化活性比经TMCS硅烷化后的稍高;气相沉积法制备的Ti/HMS经HMDSZ硅烷化后的催化活性远高于经TMCS硅烷化后的催化活性.这是由于TMCS不但能与分子筛表面的硅羟基反应,而且能破坏分子筛骨架中的Si-O-Ti甚至Si-O-Si键,形成新的羟基,导致样品的亲水性较强,同时还能对气相沉积法制备的Ti/HMS中的四配位骨架钛产生破坏作用.Ti/HMS samples were prepared by hydrothermal synthesis （HTS） and chemical vapor deposition （CVD） methods and then silylated by trimethylchlorosilane （TMCS） and hexamethyldisilazane （HMDSZ） in a vapor phase. The samples were characterized by XRD, N2 adsorption, FT-IR, ^29Si NMR, and DRUV-Vis, and their catalytic performance for the epoxidation of propylene using cumene hydroperoxide as oxidant was measured. The silylation could promote remarkably the catalytic performance. The Ti/HMS silylated by HMDSZ had much higher catalytic activity than that silylated by TMCS. This is because TMCS could not only react with silanol but also break Si-O-Ti and Si-O-Si bonds to form new silanol, which led to higher hydrophilicity for the silylated samples than those silylated by HMDSZ. The silylation with TMCS partially destroyed the tetraco- ordinated framework titanium species in Ti/HMS, but this did not occur in the silylation with HMDSZ.

关 键 词：钛 HMS分子筛 水热合成 气相沉积 硅烷化 丙烯 环氧化 

分 类 号：O643.36[理学—物理化学]