Formation of Isolated Titanium(III) Ions as Active Sites of Supported Titanium-Magnesium Catalysts for Polymerization of Olefins
Научная публикация
| Общая информация |
Язык:
Английский,
Жанр:
Статья (Full article),
Статус опубликования:
Опубликована,
Оригинальность:
Оригинальная
|
| Журнал |
Macromolecular Chemistry and Physics
ISSN: 1022-1352
, E-ISSN: 1521-3935
|
| Вых. Данные |
Год: 2014,
Том: 215,
Номер: 18,
Страницы: 1707-1720
Страниц
: 14
DOI:
10.1002/macp.201400142
|
| Ключевые слова |
catalysts, polyethylene, polypropylene, Ziegler-Natta polymerization |
| Авторы |
Mikenas Tatiana B.
1
,
Koshevoy Evgeny I.
1
,
Zakharov Vladimir A.
1,2
,
Nikolaeva Marina I.
1
|
| Организации |
| 1 |
The Laboratory of Catalytic Polymerization, Boreskov Institute of Catalysis Siberian Branch of the Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
|
| 2 |
Chemistry Department, Novosibirsk State University, St. Pirogova 2, Novosibirsk 630090, Russia
|
|
Информация о финансировании (1)
|
1
|
Министерство образования и науки Российской Федерации
|
|
Electron spin resonance (ESR) studies reveal a high yield of isolated Ti3+ compounds (30-70% of the total titanium content) that form in superactive supported titanium-magnesium catalysts (TMCs) of composition TiCl4/MgCl2 with a low titanium content (<= 0.1 wt%) after their interaction with different aluminum trialkyls (AlR3). These catalysts strongly differ from conventional TMCs with titanium contents of 1-3 wt%, which produce a set of isolated or associated Ti(II) and Ti(III) species after the interaction with the AlR3. A correlation is found between the content of the isolated Ti(III) ions and the activity in ethylene polymerization. According to temperature rising elution fractionation (TREF) data, the catalysts with a low titanium content (isolated Ti(III) ions) mainly produce polypropylene with a very high atactic-fraction content. Organic products formed on the interaction of AlEt3 and AlMe3 with TMC are identified. The data obtained allow a scheme of Ti3+ and Ti2+ compounds formed in these catalysts to be proposed.