在乙烯聚合过程中通过精准调的二氧化 (imino) 氧化 (pyridylcobalt) 预催化剂获得线性α-宏烯,具有立体和电子参数
Kainat Fatima Tahir1,2,3, Yanping Ma1, Qaiser Mahmood2
1Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Precision chemistry
|December 30, 2024
概括
研究人员开发了用于高效的乙烯聚合的新型前催化剂,产生高分子量聚乙烯. 这些催化剂能够合成功能性α-宏-olefins,这是各种应用的有价值的前体.
科学领域:
- 聚合物化学 聚合物化学
- 有机金属化学 有机金属化学
背景情况:
- 仅从乙烯合成功能性聚乙烯存在重大挑战.
- 催化剂设计,包括预催化剂结构和共催化剂选择,对于控制聚合结果至关重要.
研究的目的:
- 开发和研究用于乙烯聚合的新型前催化剂.
- 通过修改配体结构以取电子和固态组来优化催化性能.
主要方法:
- 制备一系列双 (imino) 皮里丁前催化剂,使用不同的配体替代剂 (F,NO2,基).
- 在不同条件下使用甲基氨酸 (MAO) 或改性甲基氨酸 (MMAO) 作为催化剂的乙烯聚合实验.
- 聚乙烯产品的表征使用分子量测定,分散度指数,结晶度,化温度和高温NMR光谱.
主要成果:
- 优化的预催化剂在60°C时表现出前所未有的乙烯聚合率 (高达27.6×10^6 g mol^-1 h^-1),保持活动高达100°C.
- 合成的聚乙烯具有高达61.0kg/mol的分子量,具有广泛的双模分散性.
- 主要通过β消除 (高达84.5%) 的链终结产生了维尼尔终结的长链烯酸 (α-macro-olefins).
结论:
- 设计的预催化剂可实现高效的乙烯聚合.
- 由此产生的聚乙烯具有线性微观结构和高晶度.
- 生产的α-宏-烯酸是多聚化后修饰的有价值的中间体,扩大了聚乙烯的应用.
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