高稳定性钛系聚酯催化剂TiOC@SiO_(2)的制备及应用

Preparation and application of high stability titanium polyester catalyst TiOC@SiO_(2)

钛系聚酯催化剂因催化活性高、环境友好等优点,是传统锑系聚酯催化剂的理想替代品。为了制备出耐水解性好、分散性好、催化性能稳定的钛系聚酯催化剂,采用反相微乳液法,制备得到核壳结构催化剂TiOC@SiO_(2)。在钛有机化合物的表面包覆一层硅氧烷,以此稳定钛有机化合物的催化活性。利用多种现代表征方法对TiOC@SiO_(2)的形貌、结构和性能进行了表征分析,并探究其在合成聚对苯二甲酸乙二醇酯(PET)中的催化性能。研究结果表明,TiOC@SiO_(2)催化剂为粒径约200nm的核壳球形结构,无Ti—O—Si键,钛含量为6.95%。TiOC@SiO_(2)催化剂在90℃下水浴2h后,其结构和催化活性保持不变,复合结构显著提高了钛有机化合物的耐水解性和分散性。在聚酯合成实验中,仅添加5μg/g TiOC@SiO_(2),在270℃下缩聚反应92min,即可制备出特性黏度为0.677dL/g、端羧基含量为14.4mol/t、b值为2.16的PET。

Titanium-based polyester catalysts are ideal substitutes for traditional antimony-based catalysts due to their high catalytic activity and environmental friendliness.In order to prepare titanium polyester catalyst with hydrolysis resistance,good dispersibility and stable catalytic performance,TiOC@SiO_(2)catalyst was prepared by reverse microemulsion method.A layer of siloxane was coated on the surface of titanium containing organic compound to stabilize the catalytic activity.The morphology,structure and properties of TiOC@SiO_(2)were characterized by various modern characterization methods,and its catalytic performance in the synthesis of polyethylene terephthalate(PET)was evaluated.The results showed that the TiOC@SiO_(2)catalyst had a core-shell spherical structure with a particle size of about 200nm,but no Ti—O—Si bond,and a Ti content of 6.95%.The structure and catalytic activity of TiOC@SiO_(2)catalyst remained unchanged at 90℃for 2h.The composite structure significantly improved the hydrolysis resistance of the titanium organic compounds and dispersibility.In the polyethylene terephthalate synthesis experiment,with only 5μg/g TiOC@SiO_(2)added and polycondensation at 270℃for 92min,polyester with intrinsic viscosity of 0.677dL/g,terminal carboxyl content of 14.4mol/t and b value of 2.16 was prepared.