负载型二(2-乙酰基-1-萘酚氧基)二氯化钒催化剂的制备及其催化乙烯聚合反应

分别以活性MgCl2和无水MgCl2为载体,采用浸渍法制备了负载型二(2-乙酰基-1-萘酚氧基)二氯化钒催化剂(简称负载型催化剂),并采用元素分析、红外光谱、X射线光电子能谱、X射线衍射、核磁共振和氮吸附静态容量法等手段对载体和负载型催化剂的结构进行了表征。表征结果显示,采用浸渍法制备的负载型催化剂没有改变催化活性组分的化学结构。研究负载型催化剂对乙烯聚合的性能时发现,负载型催化剂比二(2-乙酰基-1-萘酚氧基)二氯化钒均相催化剂的活性提高约一倍,所得聚乙烯的黏均相对分子质量增大;以活性MgCl2为载体的负载型催化剂的活性高。聚合动力学研究表明,负载型催化剂活性中心的稳定性好于二(2-乙酰基-1-萘酚氧基)二氯化钒均相催化剂,负载型催化剂活性中心的衰减速率较慢。

Preparation of Supported(CH3COC10H6O)2VCl2 Catalyst for Polymerization of Ethylene

Supported(CH3COC10H6O)2VCl2 catalysts were prepared by impregnation using active MgCl2 or anhydrous MgCl2 as supports.The supports and supported catalysts were characterized by means of element analysis,IR,XRD,XPS,NMR and BET.Structure of active component on supports kept unchanged after impregnation.Study on catalytic behaviors of supported catalysts indicates that activities of supported catalysts are twice as high as that of homogeneous catalysts. Viscosity-average relative molecular mass of obtained polyethylene is also higher.Because of dominant specific surface area and pore structure of active MgCl2,the obtained supported(CH3COC10H6O)2VCl2 catalyst shows higher activity than that supported by anhydrous MgCl2.Reaction kinetics shows that decaying rate of active center on supported catalysts was slower than that of homogeneous catalysts.