Half-Titanocene-Based Catalysts in the Syndiospecific Polymerization of Styrenes: Possible Oxidation States of the Titanium Species and Geometries of the Active Sites
| Autor: | Fabia Grisi, Pasquale Longo, Mariagrazia Napoli |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
chemistry.chemical_classification
Polymers and Plastics Chemistry Organic Chemistry Methylaluminoxane Solution polymerization Polymer Catalysis Styrene Inorganic Chemistry chemistry.chemical_compound Cyclopentadienyl complex Polymerization Polymer chemistry Materials Chemistry Coordination polymerization |
| Zdroj: | Macromolecules. 42:2516-2522 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/ma900041c |
| Popis: | Half-titanocenes (CpCH2CH2O)TiCl2 (1) and (CpCH2CH2OCH3)TiCl3 (2), (Cp = cyclopentadienyl), activated by methylaluminoxane (MAO), have been tested in the polymerization of styrene, p-methylstyrene, and p-chlorostyrene. Both catalysts produce syndiotactic polystyrene and poly-p-methylstyrene in the whole range of explored temperatures and concentrations. In the polymerization of p-chlorostyrene, however, catalyst 1 affords a syndiotactic polymer only at the low temperature and the high monomer concentrations; and catalyst 2 gives only an atactic product. The results have been compared to those obtained in the presence of the catalytic system CpTiCl3 (3)/MAO and have been discussed considering the possible oxidation states of the titanium species and the geometries of the active sites. |
| Databáze: | OpenAIRE |
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