オレフィンポリメリゼーション触媒の参加者として,カチオンアルキアルミニウム複合体ジルコノセン水素
Steven M Baldwin1, John E Bercaw, Hans H Brintzinger
1Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena, California 91125, United States.
Journal of the American Chemical Society
|September 24, 2010
まとめ
新型ジルコノセーン三水素カチオンがイソタキシ性ポリプロペンの形成を触媒化する. トリメチラアルミニウムの存在下では,メチル橋渡しカチオンに変換され,ポリメリゼーションプロセスと製品が変化します.
科学分野:
- 有機金属化学 有機金属化学
- ポリマーサイエンスの科学
- カタリシス カタリシス カタリシス
背景:
- ジルコノセーン複合体は,オレフィンポリメリゼーションにおける重要な触媒である.
- 触媒の特異化と変換を理解することは,ポリマーの性質を制御するために不可欠です.
研究 の 目的:
- アルキアルミニウム複合体のジルコノセーン三水化カチオンの触媒的振る舞いを調査する.
- 触媒の活性種とポリメリゼーションメカニズムを変更するトリメチラアルミニウムの役割を明らかにする.
主な方法:
- 特定の前駆物質と反応剤を用いたジルコノセーン三水化カチオンの合成.
- 低温 (-30 °C) でプロペンのポリメリゼーション実験.
- トリメチラアルミニウムの存在と欠如における触媒種の分析.
主要な成果:
- ジルコノセン三水素カチオンは,イソタキシ性ポリプロペンの形成を効率的に触媒化する.
- トリメチラアルミニウムの存在下では,トリヒドリドカチオンは,ヒドロアルミニウムによる二重メチル橋渡しのカチオンに変容します.
- この変形したカチオンは静止状態になり,AlMe (((2) コープ付きポリプロペンが形成されます.
結論:
- この研究は,共触媒の存在の影響を受けたダイナミックな触媒変換を明らかにしています.
- この変換は,ポリメリゼーション経路と最終的なポリマー構造に大きく影響し,Al-capedポリプロペンを生成します.
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