TiO2－SiO2－Al2O3／SiO2催化剂的制备及其合成PTT的催化性能研究

摘要

A TiO2-SiO2-Al2 O3/SiO2 supported catalyst was synthesized by using silica ( SiO2 ) supported titanium compounds via impregnation process .The synthesis conditions were optimized by orthogonal experiment .The obtained supported catalyst was used in the synthesis of poly ( trimethylene terephthalate ) ( PTT) and was compared with TiO 2/SiO2 catalyst in catalytic perform-ance .The results showed that the addition amounts of tetraethyl orthosilicate and deionized water gave agreat effect on the catalyt -ic performance of TiO2/SiO2 -Al2O3/SiO2;the synthesis conditions were optimized as 0.65 g tetrabutyl titanate, 80μL tetraeth-yl orthosilicate, 0.13 g aluminum isopropoxide , deionized water 240 μL; the PTT with the intrinsic viscosity of 0.871 dL/g could be synthesized when 0.65 mg/g TiO2-SiO2-Al2 O3/SiO2 based on purified terephthalic acid ( PTA) was applied in the syn-thesis of PTT under the conditions of 1,3-aluminum isopropoxide/PTA mole ratio 1.8, esterification temperature 240 ℃, poly-condensation temperature 255 ℃ and time 50 min; TiO2-SiO2-Al2 O3/SiO2 supported catalyst provided better catalytic perform-ance in the synthesis of PTT than TiO 2/SiO2 catalyst.%采用浸渍法，以二氧化硅（SiO2）负载钛（Ti）系化合物制备 TiO2－SiO2－Al2O3／SiO2负载型催化剂，并通过正交实验优化制备工艺条件，将所得到的负载型催化剂用于合成聚对苯二甲酸丙二醇酯（ PTT），同时与TiO2／SiO2催化剂的性能进行比较。结果表明：在制备 TiO2－SiO2－Al2 O3／SiO2时，正硅酸乙酯和去离子水加入量对其催化性能有较大的影响，较佳制备工艺条件为钛酸四丁酯0．65 g，硅酸乙酯80μL，异丙醇铝0．13 g，去离子水240μL；将TiO2－SiO2－Al2O3／SiO2催化剂应用于合成PTT，在其加入量（相对于精对苯二甲酸（PTA））为0．65 mg／g，1，3－丙二醇／PTA摩尔比为1．8，酯化温度240℃，缩聚反应温度255℃，缩聚时间50 min的条件下，合成的PTT特性黏数达0．871 dL／g；与TiO2／SiO2催化剂相比较，TiO2－SiO2－Al2 O3／SiO2催化剂合成PTT具有更高的催化性能。