生产聚烯烃弹性体用新茂金属催化剂合成与性质研究

In recent years, we have developed several types of new half-sandwich monocyclopentadienyltitanium complexes which show high catalytic activity, high comonomer incorporation ability and good thermostability for ethylene/-olefin copolymerization reaction upon activation with methylaluminoxane (MAO) or trialkylaluminum/trity fluorinated organoborate and can be used to produce polyolefin elastomers. However, there are still some problems to be solved by further research works. One problem is that some catalysts produce copolymers with relatively low molecular weights, which needs to be solved by further modifying the structures of the catalysts. The other problem is that the synthetic route of some catalysts is somewhat complicated and needs to be simplified to lower the cost of the catalysts. In this project, a series of new half-sandwich monocyclopentadienyl titanium catalysts are going to be designed on the basis of the structural modification of the known catalysts, and synthesized in optimized synthetic routes. Their catalytic properties for the copolymerization of ethylene with α-olefins in the presence of a suitable cocatalyst are going to be studied in detail. The effects of catalyst structure and polymerization conditions on the performance of catalysts will be examined for developing better catalysts and improving the polymerization reaction conditions. We hope that, by carrying out this research project, low-cost and high-performance new half-sandwich metallocene catalysts for the production of polyolefin elastomers could be developed.

我们课题组近些年开发出一系列适合于乙烯与α-烯烃共聚的新型单茂钛类催化剂，此类催化剂经MAO或烷基铝/五氟苯硼类助催化剂活化，可催化乙烯与α-烯烃共聚生成高共单体含量乙烯-α-烯烃共聚物，适合用于生产聚烯烃弹性体。且这些催化剂活性高，耐高温，显示出良好的发展前景。然而，仍然存在一些需要进一步研究解决的问题，如有的催化剂体系生产的聚合物分子量偏低；有的催化剂性能很好，但合成步骤较多，成本偏高。为进一步提高这些单茂钛类催化剂的性能，降低催化剂成本，本项目拟在已有工作基础上，进一步优化催化剂结构、改进催化剂合成路线，系统研究其在适当助催化剂活化下对乙烯与α-烯烃共聚反应的催化性能，探索催化剂结构与性能的关系，经过反复优化催化剂结构、催化体系和聚合反应条件，以期最终开发出具有自主知识产权、成本较低、催化乙烯与α-烯烃共聚性能优良、适合生产聚烯烃弹性体的茂金属催化剂体系。

聚烯烃弹性体在汽车配件、电线电缆、家用器具、玩具、以及塑料增韧剂等方面获得了广泛应用。开发用于生产聚烯烃弹性体、具有自主知识产权的高性能催化剂具有重要意义。在该项目资助下，我们合成了10类茂金属和非茂金属烯烃聚合催化剂，对所合成的新催化剂进行了必要的表征和组成分析，研究了其对乙烯、丙烯均聚和乙烯/1-己烯共聚反应的催化性质，获得了多种高性能催化剂体系。合成出一类含大空阻取代基芳氧基侧链单茂钛催化剂，发现其对乙烯/1-己烯共聚显示出优良的催化性能，具有良好应用前景。合成出一类含苄胺基侧臂单茂铬(IV)催化剂，对乙烯/1-己烯共聚催化性能良好，所得共聚物分子量高，共单体插入率适中。合成出两类含大空阻取代基胺双酚四齿配体钛和锆催化剂，对乙烯/1-己烯共聚催化性能良好，催化剂合成容易、寿命长、共单体插入率适中。合成出一类含大空阻取代基水杨醛亚胺钒催化剂，对乙烯/1-己烯共聚催化性能良好，不需要MAO活化，共聚物分子量较高，共单体插入率适中。合成出一类NNNN-四齿配体钛锆铪催化剂，可催化乙烯聚合生成分子量达400万以上的超高分子量聚乙烯。项目执行期间，发表SCI检索论文6篇，获得授权中国发明专利6项。