Synthesis of metallocene catalysts supported on poly[p-(silylene)phenylene] derivatives for the application to olefin polymerizations

Abstract

The polymeric [Ind 2 Si(C 6 H 4 )] n and [Ind 2 Si(C 6 H 4 ) 2 ] m compounds (Ind = indenyl) were synthesized via the condensation reaction of bisindenyldichlorosilane and p-dilithiobenzene or p-dilithiobiphenyl, and the supported-type zirconocene catalysts were prepared by reacting them with zirconium tetrachloride. The content of zirconium in the catalysts is much higher than that in the metallocene catalysts supported by inorganic compounds. Polymerizations of ethene and propene were conducted with them using methylaluminoxane (MAO) or ordinary alkylaluminiums as cocatalysts and toluene as the solvent. The catalysts combined with MAO display very high activities especially for the ethene polymerization. From the polymerization at high temperatures, it was found that the active species are markedly stabilized, probably due to the rigid backbones of the carriers. The activity of the catalysts activated with ordinary alkylaluminiums is far less as compared with those activated with MAO.

“Bound but Not Gagged”Immobilizing Single-Site α-Olefin Polymerization Catalysts

“…In the case of propylene polymerization, an enhancement in catalyst stability, stereoselectivity, and regioselectivity was observed, when compared to the corresponding mononuclear and dinuclear catalysts, Ph 2 Si(Ind) 2 ZrCl 2 and C 6 H 4 (SiPh(Ind) 2 ZrCl 2 ) 2 , respectively. However, broad molecular weight distributions were observed for polypropylene ( M w / M n = 2.9−4.5) and especially polyethylene ( M w / M n = 4.4−8.5) …”

“…Polysiloxanes derived from the hydrolysis of chloro- or alkoxy-silanes leave polymeric materials with hydroxyl groups that require capping, usually with a silane complex (HMDS or ClSiR 3 ). ,, Alt and co-workers took advantage of these functional groups to tether an ansa-bridged difluorene ligand . The hydroxyl groups of polymethylsiloxane microgels were end-capped with HOSiMe 2 (CH 2 ) 6 SiMe(Flu) 2 , Scheme .…”

“…However, broad molecular weight distributions were observed for polypropylene (M w /M n ) 2.9-4.5) and especially polyethylene (M w /M n ) 4.4-8.5). 543 Dos Santos et al have cohydrolyzed bisindenyldiethoxysilane (Ind 2 Si(OEt) 2 ) with TEOS (ratio of indene to TEOS 1:3-5) to form indene-containing xerogels that can be converted to a supported metallocene, following lithiation and metathesis with ZrCl 4 ‚2THF. 544 More recently, Deffieux and co-workers have produced an indene-modified silica support via reaction of bisindenyldichlorosilane, Me 2 SiCl 2 , (ClMe 2 Si) 2 O, and TEOS under a non-hydrolytic solgel process.…”

Immobilization of Metallocenes through Noncovalent Bonding via MAO to a Reversibly Cross-Linked Polystyrene

“…The activities of the heterogeneous runs with values between 4000 and 8000 kg PP/(mol Zr h bar) are very high in comparison with other polymer supported systems. ,, They are in the range of the activities of silica supported 5 used for polymerization in hexane …”

“…The polymer analogous synthesis of such systems in high diastereomeric purity is very complicated. Some bridged systems have been reported in the literature, which have been synthesized on a polymer carrier, ,, but none of them seems to be a single site catalyst.…”