制备条件对Pd/TiO_2催化剂上对羧基苯甲醛加氢性能的影响  

Effect of Preparation Conditions on p-Carboxy Benzaldehyde Hydrogenation Performance of Pd/TiO_2 Catalysts

作　　者：堵文斌[1] 王继元[1] 陈韶辉[1] 卞伯同[1] 曾崇余[2] 

机构地区：[1]中国石化扬子石油化工有限公司研究院,南京210048 [2]南京工业大学化学化工学院,南京210009

出　　处：《贵金属》2011年第2期9-13,共5页Precious Metals

摘　　要：采用浸渍法以TiO2成型载体制备了Pd/TiO2催化剂,考察了浸渍液pH值、Pd负载量、焙烧温度以及还原温度等因素对粗对苯二甲酸(CTA)中的主要杂质对羧基苯甲醛(4-CBA)的加氢精制性能的影响,并采用BET、XPS、XRD、H2-TPR等手段对催化剂进行了表征。结果表明,浸渍液pH值的升高会造成催化剂表面Pd原子富集,导致催化剂比表面积降低。Pd负载量0.5%时,催化剂所提供的活性中心数目足以满足4-CBA加氢所需。适当提高催化剂焙烧温度,有利于含钯前驱体的分解,催化剂还原温度过高时,会造成Pd/TiO2催化剂活性的迅速降低。Pd/TiO2催化剂的适宜制备条件为:浸渍液pH=2.0、Pd负载量0.5%、催化剂焙烧温度400℃、还原温度低于200℃。Pd/TiO2 catalysts were prepared by the impregnation method using the formed TiO2 as supports.Effect of pH values of impregnation solution,loading amounts of palladium,calcination and reduction temperatures of catalysts on the hydrogenation performance of p-carboxy benzaldehyde（4-CBA）,the main impurity in crude terephthalic acid（CTA）,was investigated.These catalysts were characterized by BET,XPS,XRD and H2-TPR techniques.It was found that the introduced palladium was accumulated on the catalyst＇ surface with the increase of pH values of impregnation solution,which led to the decrease of surface area of Pd/TiO2 catalysts.When the Pd loading amount was 0.5%,the catalyst could provide enough active sites to satisfy the hydrogenation need of 4-CBA.Suitably increasing the calcination temperature of the catalysts was favorable to the decomposition of Pd precursors.However,too high reduction temperature would lead to the remarkably decrease of catalytic activity of Pd/TiO2 catalysts.The suitable preparation conditions were advised here： the pH value of impregnation solution should be 2.0,loading amount of palladium should be 0.5%,calcination and reduction temperatures of catalyst should be 400℃ and below 200℃,respectively.

关 键 词：物理化学 对苯二甲酸 对羧基苯甲醛 加氢精制 钯 二氧化钛 负载型催化剂 

分 类 号：O643.36[理学—物理化学]