摘要
以正硅酸乙酯为硅源,正十六胺为模板剂,乙醇和水为溶剂,采用水热合成法制备了纯硅HMS介孔材料.以TiCl4为钛源,采用气相接枝技术将Ti物种引入到HMS的骨架中,制得Ti/HMS催化剂;以六甲基二硅氮烷为硅烷化试剂,采用液相接枝技术,将甲基接枝到Ti/HMS催化剂表面,以提高催化剂的疏水性.采用XRD、N2吸附、TEM、UV-Vis和FT-IR等技术表征研究了催化剂的结构、表面化学组成及疏水性;以过氧化氢异丙苯为氧化剂,分别在淤浆床及固定床反应器中,研究了Ti/HMS催化剂对丙烯的催化环氧化性能及稳定性.研究结果表明,所制备的Ti/HMS催化剂具有典型的六方介孔结构特征,且钛物种主要以四配位的活性物种形式存在于骨架中;经硅烷化试剂处理后,催化剂的疏水性得到显著提高;经硅烷化处理后的催化剂对丙烯环氧化具有优异的活性、选择性和稳定性,在2400小时的稳定性实验中,CHP的转化率维持在99.0%以上,环氧丙烷的选择性维持在97.0%以上.
Si-HMS mesoporous material was hydrothermally synthesized with tetraethyl orthosilicate as Si source, 1- hexadecylamine as template, ethanol and water as solvent. Ti speices were incorporated into the framework of Si-HMS with TiCI4 as Ti source by vapor-phase grafting technology; In order to improve the hydrophobicity of Ti/ HMS, methyl was grafted on the surface of Ti/HMS with Hexamethyl disilazane as methyl-silicon group agent by liquid-phase technology. The structure, surface chemical component and hydrophobic properties of Ti/HMS catalyst were characterized by XRD, N2 adsorption, TEM, UV-Vis and FT-IR, etc. ; The performance of catalytic epoxidation of propylene by Ti/HMS was studied in a slurry bed reactor and a fixed-bed reactor using cumene hydroperoxide as oxidant, respectively. The results showed that the prepared Ti/HMS catalysts possessed a typical mesporous structure, and Ti species existed as the tetra-coordinated form in the framework ; the hydrophobicity of Ti/HMS was obviously improved after it was treated with silane. The Ti/HMS catalyst treated by silane has excellent activity, selectivity and stability. In the period of 2400 hs performance test, the CHP conversion was over 99.0%, the selectivity to PO was over 97.0%.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2010年第1期6-11,共6页
Journal of Molecular Catalysis(China)
基金
国家重点基础研究发展规划(973计划)项目(2009CB623505)
关键词
含钛HMS催化剂
骨架钛
过氧化氢异丙苯
丙烯环氧化
Titanium-containing HMS catalyst
Framework titanium
Cumene hydroperoxide
Propylene epoxidation
