合成,表征和活动在乙烯聚合二氧化支的阴离子cyclopentadienyl氧化复合体的乙烯聚合
Nicolas Millot1, Sophie Soignier, Catherine C Santini
1Laboratoire de Chimie Organométallique de Surface, UMR 9986 CNRS--ESCPE Lyon, 43 bd du 11 Novembre 1918, F-69626 Villeurbanne Cedex, France.
Journal of the American Chemical Society
|July 20, 2006
概括
在上支的复合体表现出不同的表面环境,影响它们的反应性. 与"浮动"的阴离子催化剂相比,共价结合的催化剂在乙烯聚合中表现出更高的活性.
科学领域:
- 有机金属化学 有机金属化学
- 材料科学 材料科学 材料科学
- 催化剂是一种催化剂.
背景情况:
- 复合物在催化过程中至关重要,特别是在聚合过程中.
- 支的表面功能化提供可调节的催化性能.
- 了解有机金属前体和表面之间的相互作用是设计高效催化剂的关键.
研究的目的:
- 为了研究Cp*ZrMe3与二氧化的反应途径.
- 为了描述由此产生的表面结合的基物种.
- 评估这些物种在乙烯聚合过程中的催化活性.
主要方法:
- Cp*ZrMe3与在800°C预处理的二氧化的反应.
- 使用光谱技术 (隐含) 进行表面物种的表征.
- 在室温下进行乙烯聚合实验.
主要成果:
- 观察到两个反应途径:原溶解和甲基转移,其中原溶解占主导地位 (9:1比).
- 一个明确的表面物种,[[三重键]SiO) ZrCp* Me) 2 ,是在两个不同的局部环境中形成的.
- 与B(C6F5)3的反应产生了基于当地环境的三个不同的表面物种 (4a,4b,5).
- 在乙烯聚合过程中,联Zr催化剂 (4) 的活性 (93kg PE mol Zr−1 atm−1) 比"浮动"阴离子催化剂 (7) (67kg PE mol Zr−1 atm−1) 的活性更高.
结论:
- 表面结合的基物种的局部环境对它们的反应性有很大影响.
- 联的催化剂在乙烯聚合过程中比它们的"浮动"同类更活跃.
- 支持的有机金属复合物为开发先进的聚合催化剂提供了多功能平台.
相关概念视频
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