负载双核茂金属催化剂催化乙烯聚合反应动力学研究(英文)

Study on Kinetics of Ethylene Polymerization Catalyzed by Supported Binuclear Metallocene

以SiO2为载体,制备了负载的双核茂金属[(η5-C5H5)Zr Cl2]2[μ,μ-(SiMe2)2(η5-allyl C5H2)2]/MAO/SiO2催化剂,以己烷为溶剂进行了淤浆条件下乙烯聚合反应,研究了扩散因素、乙烯聚合压力和聚合温度对乙烯淤浆聚合动力学参数的影响,测定了聚合反应级数和表观活化能,采用动力学和相对分子质量法计算了负载催化剂的活性中心浓度,并对链增长速率常数等动力学参数进行了计算.结果表明,以负载双核茂金属催化剂催化乙烯淤浆聚合反应速率对单体浓度呈1.11级依赖,反应活化能Ea为72.47 kJ/mol,活性中心浓度C*为0.33 mol/mol,链增长速率常数Kp为1.06×106L.(mol.h)-1.

The kinetics of ethylene polymerization catalyzed by supported binuclear metallocene catalyst [（η 5-C 5 H 5） ZrCl 2 ] 2 [μ,μ-（SiMe 2） 2（η 5-allyl C 5 H 2） 2 ]/MAO/SiO 2 in slurry phase was investigated.The effects of polymerization factors,such as diffusion index,polymerization pressure and temperature on the kinetics were studied.The kinetics parameters such as reaction order（n）,the apparent activation energy（E a） and the chain propagation rate constant（K p） were determined and the concentration of active site（C ＊） was obtained by kinetic extrapolation method.The result indicates that the supported binuclear metallocene / MAO catalyst system exhibits a higher catalytic activity than that of mononuclear system,attributed to the higher C ＊ concentration and higher K p of the former.The slurry phase polymerization reaction rates show 1.11 order dependency on monomer concentration,and E a = 72.47 kJ / mol,C ＊ = 0.33 mol / mol and K p = 1.06×10 6 L.（mol.h）-1 are found.