制备方法对Ru-Zn/SiO_2催化苯选择加氢制环己烯的影响  

Effect of Preparation on Ru-Zn/SiO_2 Catalysts Performance for Selective Hydrogenation of Benzene to Cyclohexene

作　　者：王冬冬[1] 薛伟[1] 宋颖[1] 王延吉[1] 

机构地区：[1]河北工业大学绿色化工与高效节能河北省重点实验室,天津300130

出　　处：《河北工业大学学报》2010年第3期19-23,共5页Journal of Hebei University of Technology

基　　金：国家自然科学基金资助项目(20636030;20706011;20876033);天津市应用基础研究计划重点项目(07JCZDJC00100)

摘　　要：采用浸渍沉积法（I）和微乳液法（M）分别制备得到了具有相同组成的Ru-Zn/SiO2催化剂,利用程序升温还原（TPR）、X射线衍射（XRD）、透射电子显微镜（TEM）和N2等温吸附脱附技术对催化剂进行了表征.结果表明,在Ru-Zn/SiO2-I催化剂中,Ru颗粒高度分散,平均粒径-3nm;而在Ru-Zn/SiO2-M催化剂中,除高度分散的小尺寸Ru颗粒外,还存在一种直径约20-30nm,长度约100-200nm的棒状颗粒.通过苯选择加氢制环己烯反应对两种催化剂进行了评价,发现Ru-Zn/SiO2-I活性低于Ru-Zn/SiO2-M,但选择性却较高.认为这是由于Ru-Zn/SiO2-I中形成了一种壳核包覆结构的Zn/Ru颗粒,Zn壳的存在使得Ru-Zn/SiO2-I催化苯加氢反应活性较差,但反应中生成的环己烯不易发生深度加氢,因而选择性较高.Ru-Zn/SiO2 catalysts with the same content were prepared through microemulsion method and impregnationdeposition method, and were characterized by temperature-programmed reduction （TPR）, X-ray diffraction （XRD）, transmission electron microscopy （TEM） and N2 adsorption-desorption technique. It can be concluded from the results that Ru particles were dispersed uniformly with diameters about -3 nm in Ru-Zn/SiO2-Ⅰ catalyst. However, there was a kind of stick Ru particles with diameters about 20-30 nm and length about 100-200 nm existing in Ru-Zn/SiO2-M catalyst besides the highly dispersed particles. The catalytic activities were evaluated through the selective hydrogenation of benzene. Ru-Zn/SiO2-Ⅰ catalyst showed a lower activity than Ru-Zn/SiO2-M, but a higher selectivity to cyclohexene. The results were attributed to the formation of a kind of Zn/Ru particles with a shell/core structure in Ru-Zn/SiO2-Ⅰ catalyst. The zinc shell lowered the activity for hydrogenation of benzene and cyclohexene simultaneously, resulting a higher cyclohexene selectivity.

关 键 词：苯 环己烯 选择加氢 Ru-Zn/SiO2 制备方法 

分 类 号：O643.3[理学—物理化学] TQ203.2[理学—化学]