Synthesis of elastomeric polypropylene in bulk using C 1-symmetric ansa-metallocenes. New aspects of the synthesis of 1-(fluoren-9-yl)-2-(2-methyl-5,6-dihydrocyclopenta [f]-1H-inden-1-yl)ethane and complexes of zirconium and hafnium with this ligand
作者:P. M. Nedorezova、E. N. Veksler、E. S. Novikova、V. A. Optov、A. O. Baranov、A. M. Aladyshev、V. I. Tsvetkova、B. F. Shklyaruk、D. P. Krut’ko、A. V. Churakov、L. G. Kuz’mina、J. A. K. Howard
DOI:10.1007/s11172-005-0264-x
日期:2005.2
Isomeric 1-(fluoren-9-yl)-2-(2-methyl-5, 6-dihydrocyclopenta [f]-1 H-indenyl) ethanes 1a,b and C 1-symmetric metallocenes, viz., rac-1-(η5-fluoren-9-yl)-2-(2-methyl-5, 6-dihydrocyclopenta [f]-η5-inden-1-yl) ethanezirconium dichloride (9) and rac-1-(η5-fluoren-9-yl)- 2-(2-methyl-5, 6-dihydrocyclopenta [f]η5-inden-1-yl)ethanehafnium dichloride (10), with these ligands were synthesized by modified procedures. The structures of compounds 1b (two crystalline modifications) and 10 were established by X-ray diffraction analysis. The synthesis of polypropylene (PP) in bulk was studied in the presence of polymethylalumoxane-activated metallocenes 9 and 10 in the temperature range of 30–70°C. It was demonstrated that triisobutylaluminum can be used as a cocatalyst. In this case, the molecular weight of PP increases by a factor of ∼2. An increase in the reaction temperature leads to an increase in stereoregularity and crystallinity of PP. The polymer synthesized at high temperatures crystallizes in the γ form. The resulting PP is characterized by a wide range of properties from rigid crystalline thermoplastic to amorphous elastomeric. Samples, which have a high molecular weight and moderate isotacticity, exhibit high elastomeric and durability properties.
异构 1-(芴-9-基)-2-(2-甲基-5, 6-二氢环戊并[f]-1 H-茚基)乙烷 1a, b 和 C 1 对称茂金属,即、通过改进的程序合成了带有这些配体的 rac-1-(η5-芴-9-基)-2-(2-甲基-5, 6-二氢环戊并[f]-η5-茚-1-基)乙烷二氯化锆(9)和 rac-1-(η5-芴-9-基)-2-(2-甲基-5, 6-二氢环戊并[f]-η5-茚-1-基)乙烷二氯化铪(10)。通过 X 射线衍射分析,确定了化合物 1b(两种晶体修饰)和 10 的结构。在聚甲基铝氧烷活化茂金属 9 和 10 的存在下,在 30-70°C 的温度范围内研究了聚丙烯(PP)的合成。结果表明,三异丁基铝可用作助催化剂。在这种情况下,聚丙烯的分子量增加了 ∼ 2 倍。反应温度升高会导致 PP 的立体规整度和结晶度增加。在高温下合成的聚合物以 γ 形式结晶。生成的聚丙烯具有从刚性结晶热塑性塑料到无定形弹性体等多种特性。具有高分子量和中等同素异形性的样品具有较高的弹性和耐久性能。