在由高度阻碍的c(2) 对称金属催化共聚化中,从1,3-丁中获得E立体正规的1,1和1,3组成单元
Pasquale Longo1, Stefania Pragliola, Giuseppe Milano
1Università di Salerno, Dipartimento di Chimica Via S. Allende, I-84081 Baronissi Salerno, Italy.
Journal of the American Chemical Society
|April 17, 2003
概括
高度阻碍的金属催化剂在乙烯/丁共聚合中实现了前所未有的E-选择性1.1和1.3组成单元,揭示了反应机制和立体选择性的洞察力. 这促进了聚合物化学的进步.
科学领域:
- 聚合物化学 聚合物化学
- 有机金属催化工艺
背景情况:
- 烯与二烯的共聚化在控制宪法和立体化学结果方面提出了挑战.
- 金属催化剂为烯聚合提供了可调节的特性,但使用二烯实现特定的微结构仍然是复杂的.
研究的目的:
- 实现前所未有的1,1和1,3组成单位,以乙烯/丁共聚合物中的E配置.
- 阐明使用阻碍金属催化剂共聚化的机制和立体选择性.
主要方法:
- 乙烯和1,3-丁在高温和低乙烯度下联合聚合.
- 使用了一个高度阻碍的C(2) -对称的金属基因催化剂.
- 研究了聚合物微观结构和反应动力学.
- 执行了循环化反应的分子建模.
主要成果:
- 获得了前所未有的E配置的1.1和1.3组成单元的产量.
- 在标准条件下,催化剂主要形成甲-1,2-cyclopropane单位.
- 动力学分析表明,乙烯参与了旋的速率决定步骤,但不参与1,1/1,3单位的形成.
- 分子建模通过基异构化支持了E-立体选择性.
结论:
- 在乙烯/丁共聚合过程中建立了一条新的途径,以获得特定的组成单元.
- 这些发现为深入了解金属催化二烯合并提供了深入的理解.
- 这项研究通过异构化机制为观察到的E-立体选择性提供了合理化.
相关概念视频
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