Jaseer E A, Garcia Nestor, Barman Samir, Khawaji Motaz, Xu Wei, Alasiri Hassan, Peedikakkal Abdul Malik P, Akhtar Muhammad Naseem, Theravalappil Rajesh
Center for Refining and Advanced Chemicals, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
Chemicals R&D, Research and Development Center, Saudi Aramco, Dhahran 34464, Saudi Arabia.
ACS Omega. 2022 May 3;7(19):16333-16340. doi: 10.1021/acsomega.1c06657. eCollection 2022 May 17.
Tetramerization of ethylene by chromium catalysts stabilized with functionalized -aryl phosphineamine ligands CH(-CF)N(PPh) (), CH(-CF)N(PPh) (), CH(-CF)N=PPh-PPh (), and CH(3,5-bis(CF))N(PPh) () was evaluated. The parameter optimization includes temperature, co-catalyst, and solvent. Upon activation with MMAO-3A, the new catalyst system especially with -functional PNP ligand () exhibited high 1-octene selectivity and productivity while giving minimum undesirable polyethylene and C olefin by-products. Using PhCl as a solvent at 75 °C led to a remarkable α-olefin (1-C + 1-C) selectivity (>90 wt %) at a reaction rate of 2000 kg·g ·h. Under identical conditions, analogous PNP ligands bearing -CH, -Et, and -Cl functional moieties at the meta position of the -phenyl ring displayed significantly lower reactivity. The catalyst with -functional ligand () exhibited lower activity and comparable selectivities, while the Cr/PPN (with ligand ) system gave no noticeable reactivity. The molecular structure of the precatalyst (-Cr), exhibiting a monomeric structural feature, was elucidated with the aid of single-crystal X-ray diffraction study.
评估了用官能化的 - 芳基膦胺配体CH(-CF)N(PPh) ()、CH(-CF)N(PPh) ()、CH(-CF)N=PPh-PPh () 和 CH(3,5-双(CF))N(PPh) () 稳定的铬催化剂对乙烯的四聚反应。参数优化包括温度、助催化剂和溶剂。在用MMAO-3A活化后，新的催化剂体系，特别是带有 - 官能化PNP配体 () 的体系，表现出高1-辛烯选择性和生产率，同时产生的不需要的聚乙烯和C烯烃副产物最少。在75°C下以PhCl为溶剂，在2000 kg·g·h的反应速率下导致显著的α-烯烃（1-C + 1-C）选择性（>90 wt%）。在相同条件下，在 - 苯环间位带有 -CH、-Et和 -Cl官能团的类似PNP配体显示出明显较低的反应性。带有 - 官能化配体 () 的催化剂表现出较低的活性和相当的选择性，而Cr/PPN（带有配体 ）体系没有明显的反应性。借助单晶X射线衍射研究阐明了前催化剂（-Cr）的分子结构，其呈现出单体结构特征。
