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首页> 美国卫生研究院文献>Molecules >Homo-polymerization of α-Olefins and Co-polymerization of Higher α-Olefins with Ethylene in the Presence of CpTiCl2(OC6H4X-p)/MAO Catalysts (X = CH3 Cl)
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Homo-polymerization of α-Olefins and Co-polymerization of Higher α-Olefins with Ethylene in the Presence of CpTiCl2(OC6H4X-p)/MAO Catalysts (X = CH3 Cl)

机译：在CpTiCl2（OC6H4X-p）/ MAO催化剂（X = CH3Cl）存在下α-烯烃的均聚和高级α-烯烃与乙烯的共聚

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Cyclopentadienyl-titanium complexes containing –OC6H4X ligands (X = Cl, CH3) activated with methylaluminoxane (MAO) were used in the homo-polymerization of ethylene, propylene, 1-butene, 1-pentene, 1-butene, and 1-hexene, and also in co-polymerization of ethylene with the α-olefins mentioned. The -X substituents exhibit different electron donor-acceptor properties, which is described by Hammett’s factor (σ). The chlorine atom is electron acceptor, while the methyl group is electron donor. These catalysts allow the preparation of polyethylene in a good yield. Propylene in the presence of the catalysts mentioned dimerizes and oligomerizes to trimers and tetramers at 25°C under normal pressure. If the propylene pressure was increased to 7 atmospheres, CpTiCl2(OC6H4CH3)/MAO catalyst at 25°C gave mixtures with different contents of propylene dimers, trimers and tetramers. At 70°C we obtained only propylene trimer. Using the catalysts with a -OC6H4Cl ligand we obtained atactic polymers with Mw 182,000 g/mol (at 25°C) and 100,000 g/mol (at 70°C). The superior activity of the CpTiCl2(OC6H4Cl)/MAO catalyst used in polymerization of propylene prompted us to check its activity in polymerization of higher α-olefins (1-butene, 1-pentene, 1-hexene) and in co-polymerization of these olefins with ethylene. However, when homo-polymerization was carried out in the presence of this catalyst no polymers were  obtained. Gas chromatography analysis revealed the presence of dimers. The activity of the CpTiCl2(OC6H4Cl)/MAO catalyst in the co-polymerization of ethylene with higher α-olefins is limited by the length of the co-monomer carbon chain. Hence, the highest catalyst activities were observed in co-polymerization of ethylene with propylene (here a lower pressure of the reagents and shorter reaction time were applied to obtain catalytic activity similar to that for other co-monomers). For other co-monomers the activity of the catalyst decreases as follows: propylene >1-butene > 1-pentene >> 1-hexene. In the case of co-polymerization of ethylene with propylene, besides an increase in catalytic activity, an increase in the average molecular weight Mw of the polymer was observed. Other co-monomers used in this study caused a decrease of molecular weight. A significant increase in molecular weight distribution (Mw/Mn) evidences a great variety of polymer chains formed during the reaction.
机译：含有由甲基铝氧烷（MAO）活化的–OC6H4X配体（X = Cl，CH3）的环戊二烯基钛络合物用于乙烯，丙烯，1-丁烯，1-戊烯，1-丁烯和1-己烯的均聚，以及乙烯与上述α-烯烃的共聚。 -X取代基表现出不同的电子给体-受体性质，这由哈米特因子（σ）来描述。氯原子是电子受体，而甲基是电子供体。这些催化剂允许以良好的产率制备聚乙烯。在所述催化剂的存在下，丙烯在常压下于25℃下二聚并低聚为三聚体和四聚体。如果将丙烯压力增加至7个大气压，则在25℃下的CpTiCl 2（OC 6 H 4 CH 3）/ MAO催化剂得到具有不同含量的丙烯二聚物，三聚物和四聚物的混合物。在70℃下，我们仅获得丙烯三聚体。使用具有-OC 6 H 4 Cl配体的催化剂，我们获得了Mw为182,000 g / mol（在25°C）和100,000 g / mol（在70°C）的无规立构聚合物。用于丙烯聚合的CpTiCl2（OC6H4Cl）/ MAO催化剂具有优异的活性，促使我们检查其在高级α-烯烃（1-丁烯，1-戊烯，1-己烯）的聚合以及它们的共聚中的活性。烯烃与乙烯。但是，当在这种催化剂存在下进行均聚时，没有得到聚合物。气相色谱分析表明存在二聚体。 CpTiCl2（OC6H4Cl）/ MAO催化剂在乙烯与高级α-烯烃共聚中的活性受到共聚单体碳链长度的限制。因此，在乙烯与丙烯的共聚中观察到最高的催化剂活性（此处使用较低的试剂压力和较短的反应时间以获得类似于其他共聚单体的催化活性）。对于其他共聚单体，催化剂的活性降低如下：丙烯> 1-丁烯> 1-戊烯 1-己烯。在乙烯与丙烯共聚的情况下，除了催化活性增加外，还观察到了聚合物的平均分子量M ww的增加。本研究中使用的其他共聚单体导致分子量降低。分子量分布（M w / M n ）的显着增加表明反应期间形成了多种聚合物链。

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