实验和第一原则调查支持形态如何决定在乙烯聚合过程中齐格勒-纳塔催化剂的性能
Tinnakorn Saelee1,2,3, Pichayapong Sitthijun2, Chinanang Ngamlaor1,2
1High-Performance Computing Unit (CECC-HCU), Center of Excellence on Catalysis and Catalytic Reaction Engineering (CECC), Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand.
Scientific reports
|August 1, 2024
概括
使用TiCl4/MgCl2预处理齐格勒-纳塔催化剂 (ZNC),可以通过形成TiCl4集群来降低活性. MgCl2 (110) 表面防止了这种聚类,提高了ZNC的性能和稳定性.
科学领域:
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
- 聚合物化学 聚合物化学
背景情况:
- 齐格勒-纳塔催化剂 (ZNC),特别是TiCl4/MgCl2与三乙烯 (AlEt3) 的催化剂,对于乙烯聚合是至关重要的.
- 虽然物种是关键的活性点,但增加的负载并不总是促进ZNC活动.
研究的目的:
- 为了研究TiCl4沉积增加在预处理过程后对ZNC活动的反作用.
- 阐明催化剂表面结构和TiCl4集群在ZNC失活中的作用.
主要方法:
- 对ZNC性能进行实验性调查.
- 密度函数理论 (DFT) 计算以建模催化剂相互作用和反应机制.
主要成果:
- 与未经预处理的催化剂相比,预处理的ZNC的活性下降了60%.
- DFT 发现预处理加强了 TiCl4 相互作用,在 (104) 表面形成了 TiCl4-TiCl4 集群.
- 这些集群阻碍了三乙烯的吸附和化,导致不活跃的Ti位点.
- 在 (110) 表面的TiCl4聚合不太有利,允许有效的激活和聚合.
结论:
- 在ZNC表面,特别是 (104) 平面上,TiCl4-TiCl4集群的形成会导致失活.
- 存在的MgCl2 (110) 平面显著抑制TiCl4聚类.
- 通过暴露 (110) 平面来优化ZNC是提高催化剂性能和稳定性的关键.
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