Et3Al and Et2Zn cooperatively enhanced Ti catalyzed ethylene coordinative chain transfer polymerization

• Published in: Journal of catalysis Vol. 438; p. 115688
• Main Authors: Zhu, Boyu, Ning, Xiao-Shan, Li, Peizhi, Zhang, Bolun, Ji, Li, Gao, Yanshan, Zhou, You-Yun, Sun, Xiu-Li, Zhao, Yanan, Han, Xing-Wang, Kuang, Xiaokang, Tang, Yong
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.10.2024
• Subjects: Chain transfer; Diethylzinc; Ethylene polymerization; Poisoning effects; Triethylaluminum; Poisoning effects; Ethylene polymerization; Chain transfer; Triethylaluminum; Diethylzinc
• ISSN: 0021-9517
• DOI: 10.1016/j.jcat.2024.115688

[Display omitted] •A method for enhancing Ti catalyzed ethylene chain transfer polymerization efficiency.•Using AlEt3 and ZnEt2 shows cooperative effects vs. using them separately.•Chain growth and transfer are simultaneously enhanced in ethylene polymerization. Developing olefin polymerization catalytic systems for both high activity and high chain transfer efficiency by using coordinative chain transfer polymerization (CCTP) is critical for the controlled synthesis of various novel high-value polyolefin materials. While the limited choice of chain transfer agents (CTAs) makes it a challenge to achieve highly efficient CCTP as well as chain propagation due to their competition during the polymerization. Here we report using the combination of R3Al and R2Zn in equal amount for tetradentate amine-bis(phenolate) Ti complex and tridentate ketoiminate Ti complex catalyzed ethylene polymerization and observed significantly enhanced CCTP catalytic performance in terms of activity, chains/cat, fill ratio, and kct/kp vs. using R3Al as CTA. The role of R3Al and R2Zn during ethylene polymerization were probed by preliminary control experiments studies and a possible mechanistic scenario was proposed.