焙烧温度对TiO2成型载体性能的影响

以偏钛酸为原料，采用挤条成型的方法制备TiO₂成型载体。考察焙烧温度对TiO₂成型载体抗压强度、比表面积、孔容、孔径分布和晶相结构等的影响，采用XRD、BET、TG-DSC和SEM等手段对载体进行表征，并采用浸渍法制备了用于粗对苯二甲酸加氢精制的Pd/TiO₂催化剂。结果表明，提高焙烧温度有利于提高成型载体的侧压强度，但会使成型载体的比表面积和孔容降低，孔径分布向大孔方向位移。焙烧温度超过800 ℃，锐钛型TiO₂成型载体的晶型结构发生相变，逐步转变成金红石型。600 ℃制备的TiO₂成型载体的侧压强度在110 N·cm^－1以上，比表面积达60 m²·g^－1。并用TiO₂成型载体制备了质量分数0.5%Pd/TiO₂催化剂，用于对苯二甲酸加氢精制过程，4-CBA转化率达99%以上，为对苯二甲酸加氢精制催化剂研究提供了新的载体。酸

Effects of calcination temperature on properties of formed TiO2 support

Formed TiO₂ support was prepared by extrusion using low cost metatitanic acid as starting material. The influence of calcination temperature on crush strength, surface area, pore volume, pore size distribution and crystal phase of the formed TiO₂ supports were investigated, and the supports were characterized by XRD, BET, TG/DSC and SEM. Pd/TiO₂ catalyst for hydrofining of raw terephthalic acid was prepared by impregnation. The results showed that higher calcination temperature favored higher crush strength but led to declining surface area and pore volume, and shift to macropores distribution. Crystal phase transformation of TiO₂ supports from anatase to rutile occurred at calcination temperature of over 800 ℃. The formed TiO₂ support calcined at 600 ℃ had crush strength of over 110 N·cm^－1 and surface area of 60 m²·g^－1. 0.5%Pd/TiO₂ catalyst was prepared and used in hydrofining of raw terephthalic acid, with 4-CBA conversion of over 99%.