Effects of calcination temperature on properties of formed TiO_2 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%.