<i>In Situ</i> Activation: Chances and Limitations to Form Ultrahigh Molecular Weight Syndiotactic Polypropylene with Metallocene Dichlorides
作者:Lucas Stieglitz、Daniel Henschel、Thomas Pehl、Bernhard Rieger
DOI:10.1021/acs.organomet.1c00397
日期:2021.12.27
molecular weight of polypropylene (PP), whereas the polymerization with the corresponding hafnocene Ib (HfCl2[Me2C(η5-Flu)(η5-Cp)]) resulted in a lower productivity and stereoregularity but yielded ultrahigh molecular weight polypropylene (Mw = 1100 kg mol–1). The backbone in II (HfCl2[Ph2C(η5-Flu)(η5-Cp)]) was associated with a higher productivity and molecular weight, while the syndiotacticity was not affected
合成了具有不同桥接基序(C 和 Si)的芴基环戊二烯基C s对称柄型茂金属(M = Zr,Hf)配合物I - IV,随后在丙烯的间规配位聚合中进行了检测。所有复合物活化原位用三异丁基铝(TIBA)和[PH 3 C] [B(C 6 ˚F 5)4,以突出的这样的好处(TrBCF)原位活化,导致与甲基铝氧烷 (MAO) 相比显着更高的分子量和显着提高的生产率。异丙叉桥联的二茂锆Ia (ZrCl 2 [Me 2 C(η 5 -Flu)(η 5 -Cp)]) 表现出高生产率 (80000 kg PP (mol cat h) -1 ) 和立构规整性 ([rrrr] up至 93%) 与中等分子量的聚丙烯 (PP),而与相应的铪茂Ib (HfCl 2 [Me 2 C(η 5 -Flu)(η 5-Cp)]) 导致较低的生产率和立构规整性,但产生超高分子量聚丙烯 ( M w = 1100 kg mol –1