论文部分内容阅读
合成了不对称异双核钴镍催化剂MN5CoNi.该催化剂经AlEt3,MMAO,AlEt3/[PhMe2NH][B(C6F5)4](B)或MMAO/B活化后用于乙烯聚合.异双核催化剂与相应的等摩尔双组分混合单核催化剂相比,以TEA作助催化剂时,异双核催化剂的Co和Ni中心的活性都远低于双组分混合体系,且Ni中心生成的聚乙烯含量低于双组分混合体系,异双核催化剂中的Co和Ni中心同时被抑制.以MMAO作助催化剂时,异双核催化剂的活性虽低于双组分混合体系,但是异双核催化剂中的两种金属中心的活性都有了较大的提高,且Ni中心生成的聚乙烯含量高于后者.同时考察了活性随时间变化,发现异双核催化剂中活性衰减比双组分混合体系慢,说明异双核体系中Co和Ni中心在MMAO活化下比双组分混合体系的金属中心更稳定.当以TEA/B作助催化剂时,异双核催化剂中Co和Ni中心的活性有所提高,但仍远低于双组分混合体系,且Ni中心生成的聚乙烯含量低于后者,说明Ni被选择性抑制.当使用MMAO/B作助催化剂时,结果与MMAO类似.
The asymmetric heterobonuclear cobalt-nickel catalyst MN5CoNi was synthesized and used for ethylene polymerization after being activated by AlEt3, MMAO, AlEt3 / [PhMe2NH] [B (C6F5) 4] (B) or MMAO / When using TEA as cocatalyst, the activity of Co and Ni centers of heterobinuclear catalysts are much lower than that of two-component mixed system, and the content of polyethylene in the center of Ni is lower than that of bis In the mixed system, the Co and Ni centers in the heterobinuclear catalyst are inhibited simultaneously.When MMAO is used as cocatalyst, the activity of heterobinuclear catalyst is lower than that of the two-component mixed system, but the two metal centers in heterobinuclear catalyst The activity of polyethylene in the heteronuclear catalyst is much higher than that in the two-component system, indicating that the content of polyethylene in the center of Ni is higher than that in the latter .At the same time, The Co and Ni centers are more stable than the metal centers of the two-component mixed system under the activation of MMAO.When TEA / B is used as a cocatalyst, the activity of Co and Ni centers in heterobinuclear catalysts is improved, but still much lower than that of bis Component mixed system, and Ni center generated An ethylene content lower than the latter, indicating that Ni is selectively suppressed when using MMAO / B as cocatalyst, MMAO similar results.