钾修饰SiO_2负载超低含量过渡金属催化剂上乙烷选择氧化反应  

Selective Oxidation of Ethane over the Potassium-modified Silica-supported Super Low Loading Transition Metal Catalysts

作　　者：张哲[1] 赵震[1] 徐春明[1] 段爱军[1] 王宏宣[1] 

机构地区：[1]中国石油大学重质油国家重点实验室,北京102249

出　　处：《分子催化》2006年第1期17-22,共6页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金(20373043);教育部支持留学归国人员科学研究及实验室建设重点基金

摘　　要：制备了一系列碱金属K修饰的S iO2负载的超低含量过渡金属(K∶M∶S i=10∶1∶1000,摩尔比,M=V、Cr、Mn、Fe、Co、N i、Cu和Zn)催化剂,考察了该系列催化剂对乙烷分子氧选择氧化生成醛类含氧化合物的反应性能.引入钾促进了S iO2负载的超低含量过渡金属催化剂上乙烷选择氧化生成乙醛和丙烯醛.钾修饰的S iO2负载超低含量过渡金属催化剂上,相对稳定的全充满、半充满或无d电子的表面离子有利于乙烷选择氧化反应进行,而存在多种价态的相对不稳定的离子结构有利于乙烷深度氧化的进行.The potassium-modified silica-supported very low loading transition metal catalysts （K： M： Si = 10： 1 ： 1000, mol, M = V, Cr, Mn, Fe, Co, Ni, Cu, Zn） were prepared. The catalytic performances of K-M/SiO2 catalysts for the selective oxidation of ethane using oxygen as oxidant were measured and these catalysts were characterized by means of UV-Vis spectra. The result showed that using the very low loading silica-supported transition metal oxide catalysts modified by potassium, not only was aldehyde detected, but also acrolein was obtained from the products of ethane selective oxidation reaction. The different absorption bands and peaks of UV-Vis spectra were assigned to ligand-to-metal charge transfer （LMCT） of O^2- on surface sites to M^n＋ or the d-d field transition. The relation between the ion structure of transition metal and the performance of catalysts was established and it was found that the stable ion structures with d-orbitals which are fully occupied or half occupied or empty are good for the selective oxidation of ethane to aldehydes, while the ions which have the relatively unstable d-electron structures with mixed valences are good for the deep oxidation of ethane.

关 键 词：超低含量 过渡金属 催化剂 乙烷 选择氧化 

分 类 号：O643.32[理学—物理化学]