Propene polymerization with the MgCl2-supported dichlorobis(?-diketonato)titanium catalysts activated by ordinary alkylaluminums

Abstract

Several kinds of dichlorobis(β‐diketonato)titanium complexes, i.e., Ti(ace‐tylacetonato)2Cl2, Ti(1‐benzoylacetonato)2Cl2, Ti(2,2,6,6‐tetramethyl‐3,5‐heptanedionato)2Cl2 and Ti(4,4,4‐trifluoro‐1‐phenyl‐1,3‐butanedionato)2Cl2, were synthesized and the corresponding MgCl2‐supported catalysts were prepared by impregnation method. The test of them for propene polymerization revealed that those MgCl2‐supported catalysts could be activated not only by methylaluminoxane (MAO) but also by ordinary alkylaluminums as well. The effect of typical Lewis bases on the catalyst performance was investigated in some detail, which indicated that organic silanes are most effective for the improvement of isospecificity of those catalysts. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 129–135, 1998

Development of novel MgCl2 supported catalyst with trivalent titanocene complex of CP2TiCl2AlCl2 for propylene polymerization

“…Taking into account the fact that the polymerization activity by CpTiCl 3 combined with alkylaluminums is almost negligible, it seems that MgCl 2 plays an important role in the polymerization activity. Similar results were obtained with Ti(acac) 2 Cl 2 /MgCl 2 (acac, acetylacetonato) 6. It is considered that the resulting active species consist of trivalent titaniums with an alkyl group, comparable with those in conventional Ziegler–Natta catalysts 5, 6.…”

“…Similar results were obtained with Ti(acac) 2 Cl 2 /MgCl 2 (acac, acetylacetonato) 6. It is considered that the resulting active species consist of trivalent titaniums with an alkyl group, comparable with those in conventional Ziegler–Natta catalysts 5, 6. From such a viewpoint, we tried to develop a novel catalyst by supporting the trivalent titanium complexes on MgCl 2 and evaluate the catalytic performance for the propylene polymerization.…”

“…In olefin polymerizations with conventional Ziegler–Natta catalysts, it is well known that the isospecificity of the catalyst is drastically improved by the addition of a suitable Lewis base like EB, di‐ n ‐butyl phthalate, phenyltriethoxysilane, and so on 9. We previously reported that these electron donors are effective even for CpTiCl 3 /MgCl 2 ,5 Ti(acac) 2 Cl 2 /MgCl 2 ,6 and Cr(acac) 3 /MgCl 2 (ref. 10) catalysts.…”

“…As a result, the highly isospecific catalyst was successfully prepared by adding DIPDMS as the external donor, which produced PP with the II as high as 98.4%, even without using any internal donors. According to our knowledge, only a few catalyst systems, which do not use any internal donors6, 10 or external donors,11 can produce isotactic PP with a selectivity over 98%. As compared with the tetravalent titanium based catalysts like CpTiCl 3 /MgCl 2 (ref.…”

Heterogeneous Single-Site Catalysts for Olefin Polymerization

“…The polypropylene produced is atactic, but isotactic polymer is formed when an external donor such as ethylbenzoate is added . A similar pattern is observed when bis(diketonato) metal dihalides are supported on MgCl 2 . The titanium-based catalysts are far more active than the zirconium analogues: (acac) 2 TiCl 2 −MgCl 2 −Al( i -Bu) 3 (acac = acetylacetone) has an activity of 310 kg/mol M·h vs 1.1 kg/mol M·h for (acac) 2 ZrCl 2 −MgCl 2 −Al( i -Bu) 3 .…”