双核茂钛催化剂中苄基苯环的弱作用效应对乙烯聚合行为影响的研究

发布时间：2018-05-13 16:48

本文选题：苄基 + 双核茂金属　；参考：《有机化学》2017年05期

【摘要】：为了研究茂环上的苄基对双核茂金属催化行为的影响,合成了含有苄基的桥连双核茂金属[(η~5-C_5H_5)TiCl_2(η~5-(C_6H_5)C(Me)_2(C_5H_3)]2[μ,μ-1,4-(CH_2)2(C_6H_4)][(TiBz)_2],通过~1HNMR、~(13)C NMR、质谱和元素分析进行了表征,确认了化学结构.在甲基铝氧烷(MAO)助催化作用下(TiBz)_2催化乙烯聚合得到C(4)支链的聚乙烯,C(4)支链源自于苄基苯环弱作用效应导致的乙烯三聚产生的1-己烯对聚乙烯插入.该催化体系具有很好的共聚能力,催化乙烯与1-己烯共聚时,聚合物中1-己烯插入率高达13.7 mol%,且形成交替共聚片段结构.对其特殊的催化循环机理进行了探讨,苄基苯环与中心金属弱相互作用导致1-己烯与乙烯分子交替插入得到己烯乙烯交替共聚(HEHE)片段,聚合物较窄的分子量分布(PDI=2.23)表明,在聚合过程中两个金属中心产生了强烈的协同效应,使其共聚能力大幅度提高.
[Abstract]:In order to study the effect of benzyl group on the catalytic behavior of binuclear metallocene, a novel binuclear metallocene with benzyl group was synthesized. [(畏 _ 5-C _ 5H _ 5H _ 5H _ 5H _ 5H _ 5T _ 2T _ 2C _ 5H _ 5H _ 5C _ 5H _ (3)] 2 [渭, 渭 -14-CH2H2C _ 6H _ 4] [TiBzhe _ 2], characterized by 1HNMR-13C NMRs, mass spectrometry and elemental analysis. In the presence of methyl aluminoxane (MAO), TiBzf2 was used to catalyze ethylene polymerization to obtain Cn4) the branched chain originated from the insertion of 1-hexene into polyethylene by ethylene trimerization due to the weak effect of benzyl benzene ring. When ethylene was copolymerized with 1-hexene, the insertion rate of 1-hexene in the polymer was up to 13.7 mol / mol, and the structure of alternating copolymerization fragment was formed. The special mechanism of catalytic cycle was discussed. The weak interaction between benzyl benzene ring and central metal resulted in the intercalation of 1-hexene and ethylene to produce the hexene alternating copolymerization (HEHEH) fragment, and the narrower molecular weight distribution of the polymer (PDI _ (2.23) indicated that, The two metal centers have a strong synergistic effect during the polymerization process, which greatly improves the copolymerization ability of the two metal centers.
【作者单位】：华东理工大学化学与分子工程学院;
【基金】：国家自然科学基金(No.U1362111)资助项目~~
【分类号】：O632.12;O643.36

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