Ti-HMS合成、表征及其催化氧化性能研究  

Synthesis,Characterization and Catalytic Oxidation Activity of Ti-HMS

作　　者：俞卫华[1] 周春晖[1] 倪哲明[1] 张波[1] 葛忠华[1] 

机构地区：[1]浙江工业大学化学工程与材料学院浙江省多相催化重点实验室,浙江杭州310014

出　　处：《高校化学工程学报》2007年第5期779-783,共5页Journal of Chemical Engineering of Chinese Universities

基　　金：浙江省自然科学基金资助项目(405025);国家自然科学基金资助项目(20541002)

摘　　要：以有机金属二氯二茂钛为钛源,六方介孔二氧化硅分子筛(HMS)为载体,采用嫁接法合成了含钛量(mol)分别为2.8%、3.8%和4.8%的Ti-HMS,HMS合成原料组成中H2O/EtOH(v/v)分别为0.5、1、2、5、9。合成材料用X射线粉末衍射(XRD)、N2吸附-脱附等温线、漫反射紫外可见光谱(UV-VIS)进行了表征,并考察了它们以叔丁基过氧化物(TBHP)为氧化剂在对叔丁基甲苯液相氧化中的催化性能。结果表明,表面钛嫁接后的HMS介孔结构有所损失,比表面积和孔体积减少。载体HMS合成原料中的H2O/EtOH(v/v)影响介孔织构和钛的配位环境。UV-VIS资料表明,H2O/EtOH(v/v)=0.5和9时不利于钛着床于分子筛骨架,H2O/EtOH(v/v)=1、2和5的HMS适合作为嫁接钛的载体。催化剂的活性主要受四配位Ti、介孔织构的影响。钛嫁接的HMS在氧化反应中表现出较好的催化活性,载钛量为4.8%Ti、H2O/EtOH(v/v)=1的Ti-HMS显示最好催化活性,对叔丁基甲苯转化率为21.8%。Using the organometallic precursor titanocene dichloride as titanium source and hexagonal mesoporous silica （HMS） prepared with different H2O/EtOH（v/v） = 0.5, 1, 2, 5 and 9 as supports, the Ti-HMS catalysts with loading 2.8%, 3.8% and 4.8 mol% titanium content were prepared by grafting method. The catalysts prepared were characterized by powder X-ray diffraction （XRD）, nitrogen adsorption-desorption isotherms, and diffuse reflectance UV visible spectroscopy （UV-VIS）. The catalytic performances of Ti-HMS prepared were tested by the oxidation reaction of 4-tert-butyltoluene in the liquid phase with tert-butylhydroperoxide （TBHP） as oxidant. The results show that grafting Ti onto the surface of HMS leads to damage to the mesostructure of HMS and decrease its surface area and its pore volume. The UV-VIS spectra show that the textural mesopores of HMS and the coordination environment of Ti（IV） are influenced by H2O/EtOH（v/v）, and H2O/EtOH（v/v）=0.5 and 9 do not favor Ti atom being in four-coordinated state, while H2O/EtOH（v/v）=I, 2 and 5 afford higher amount of isolated Ti（IV） framework sites. The catalytic activity of Ti-HMS depends on the amount of tetrahedral-coordinated Ti atoms and the textural mesopores of HMS. The grafted -Ti HMS samples exhibit high activities in the oxidation reactions, and Ti-HMS with loading 4.8% Ti and H2O/EtOH（v/v）= 1 gives a maximum 4-tert-butyltoluene conversion of 21.8%.

关 键 词：嫁接 TI-HMS 对叔丁基甲苯 氧化 

分 类 号：O643.361[理学—物理化学] TQ426.61[理学—化学]