载体对钒铬氧化物催化剂结构及催化3-甲基吡啶氨氧化反应活性的影响(英文)  

Effect of supports on the structure and activity of vanadium-chromium oxide catalysts for ammoxidation of 3-picoline

作　　者：姜枫[1] 邓生财[2] 牛磊[1] 肖国民[1] 

机构地区：[1]东南大学化学化工学院,江苏南京211189 [2]南京大学化学化工学院 介观化学教育部重点实验室 江苏省纳米技术重点实验室,江苏南京210093

出　　处：《催化学报》2013年第10期1833-1838,共6页

基　　金：the National Natural Science Foundation of China(21276050);the National Key Technology R&D Program(2012BAD32B03)~~

摘　　要：通过等体积浸渍法制备了Nb2O5,MgF2,TiO2和SiO2负载和未负载的钒铬氧化物催化剂,并应用X射线衍射、N2吸附-脱附、H2程序升温还原和NH3程序升温脱附对催化剂进行了表征.结果表明,催化剂比表面积较大时有利于CrVO4-I(单斜)的生成,比表面积较小则有利于CrVO4-III(斜方)的生成.在310–400℃下3-甲基吡啶氨氧化制备3-氰基吡啶反应中,具有较高催化活性的催化剂与V物种还原性较高和表面活性位数量较多有关;而高的3-氰基吡啶选择性则与催化剂表面较低的酸性密切相关.升高反应温度可大幅度提高催化剂的活性,且其选择性基本不变.Bulk and Nb2 O5 -,MgF2 -,TiO2 -,and SiO2 -supported vanadium-chromium oxide catalysts were prepared by the incipient wetness impregnation method and investigated for the ammoxidation of 3-picoline to nicotinonitrile at 310–400℃.The physical and chemical properties of the catalysts were assessed by X-ray diffraction,N2 adsorption-desorption,H2 -temperature-programmed reduction,and NH3 -temperature-programmed desorption.The surface area of the supports influenced the formation of the active components of the catalysts: high surface area encouraged the formation of monoclinic CrVO4 whereas low surface area favored the formation of orthorhombic CrVO4.The high reducibility of vanadium in the catalyst and the large number of surface active sites resulted in higher 3-picoline conversion efficiencies.The high selectivity was attributed to the low surface acidity of the catalysts.Reaction temperature showed a positive effect on the catalytic performance for it could increase 3-picoline conversion and maintain nicotinonitrile selectivity.

关 键 词：氨氧化 3-甲基吡啶 3-氰基吡啶 载体 钒铬氧化物 

分 类 号：O643.32[理学—物理化学]