Molecules 2005, 10(6), 659-671; doi:10.3390/10060659
Article

Homo-polymerization of α-Olefins and Co-polymerization of Higher α-Olefins with Ethylene in the Presence of CpTiCl2(OC6H4X-p)/MAO Catalysts (X = CH3, Cl)

* email, email,  and
Received: 5 August 2004; Accepted: 23 September 2004 / Published: 4 July 2005
(This article belongs to the Special Issue Synthesis and Chemistry of Chiral Metallocenes)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Cyclopentadienyl-titanium complexes containing –OC6H4X ligands (X = Cl,CH3) activated with methylaluminoxane (MAO) were used in the homo-polymerizationof ethylene, propylene, 1-butene, 1-pentene, 1-butene, and 1-hexene, and also in co-polymerization of ethylene with the α-olefins mentioned. The -X substituents exhibitdifferent electron donor-acceptor properties, which is described by Hammett’s factor (σ).The chlorine atom is electron acceptor, while the methyl group is electron donor. Thesecatalysts allow the preparation of polyethylene in a good yield. Propylene in the presenceof the catalysts mentioned dimerizes and oligomerizes to trimers and tetramers at 25oCunder normal pressure. If the propylene pressure was increased to 7 atmospheres,CpTiCl2(OC6H4CH3)/MAO catalyst at 25oC gave mixtures with different contents ofpropylene dimers, trimers and tetramers. At 70oC we obtained only propylene trimer.Using the catalysts with a -OC6H4Cl ligand we obtained atactic polymers with Mw182,000 g/mol (at 25oC) and 100,000 g/mol (at 70oC). The superior activity of theCpTiCl2(OC6H4Cl)/MAO catalyst used in polymerization of propylene prompted us tocheck its activity in polymerization of higher α-olefins (1-butene, 1-pentene, 1-hexene)and in co-polymerization of these olefins with ethylene. However, when homo-polymerization was carried out in the presence of this catalyst no polymers wereobtained. Gas chromatography analysis revealed the presence of dimers. The activity ofthe CpTiCl2(OC6H4Cl)/MAO catalyst in the co-polymerization of ethylene with higher α-olefins is limited by the length of the co-monomer carbon chain. Hence, the highest catalyst activities were observed in co-polymerization of ethylene with propylene (here a lower pressure of the reagents and shorter reaction time were applied to obtain catalytic activity similar to that for other co-monomers). For other co-monomers the activity of the catalyst decreases as follows: propylene >1-butene > 1-pentene >> 1-hexene. In the case of co-polymerization of ethylene with propylene, besides an increase in catalytic activity, an increase in the average molecular weight Mw of the polymer was observed. Other co- monomers used in this study caused a decrease of molecular weight. A significant increase in molecular weight distribution (Mw/Mn) evidences a great variety of polymer chains formed during the reaction.
Keywords: Hemititanocene; ethylene; propylene; 1-butene; 1-pentene; 1-hexene; co- polymerization of ethylene
PDF Full-text Download PDF Full-Text [187 KB, uploaded 18 June 2014 19:26 CEST]

Export to BibTeX |
EndNote


MDPI and ACS Style

Skupinski, W.; Nicinski, K.; Jamanek, D.; Wieczorek, Z. Homo-polymerization of α-Olefins and Co-polymerization of Higher α-Olefins with Ethylene in the Presence of CpTiCl2(OC6H4X-p)/MAO Catalysts (X = CH3, Cl). Molecules 2005, 10, 659-671.

AMA Style

Skupinski W, Nicinski K, Jamanek D, Wieczorek Z. Homo-polymerization of α-Olefins and Co-polymerization of Higher α-Olefins with Ethylene in the Presence of CpTiCl2(OC6H4X-p)/MAO Catalysts (X = CH3, Cl). Molecules. 2005; 10(6):659-671.

Chicago/Turabian Style

Skupinski, W.; Nicinski, K.; Jamanek, D.; Wieczorek, Z. 2005. "Homo-polymerization of α-Olefins and Co-polymerization of Higher α-Olefins with Ethylene in the Presence of CpTiCl2(OC6H4X-p)/MAO Catalysts (X = CH3, Cl)." Molecules 10, no. 6: 659-671.

Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert