Switching a Catalyst System from Ethene Polymerization to Ethene Trimerization with a Hemilabile Ancillary Ligand

Abstract

A drastic ligand effect was observed in the catalytic ethene conversion by the substituted mono(cyclopentadienyl)titaniumtrichloride/methylalumoxane (MAO) catalysts shown. The catalyst with R=Me produces polyethene, whereas the catalyst with R=Ph selectively trimerizes ethene to 1‐hexene. This switch in catalyst performance appears to be the result of a hemilabile behavior of the cyclopentadienyl ligand with the pendant arene group, involving reversible coordination of the arene moiety.

Oligomerization of Monoolefins by Homogeneous Catalysts

“…With an appropriate choice of metal-ligand and metal activator combination, it is possible to selectively obtain oligomers instead of high molecular weight polymers [3]. The regioselectivity of homogeneous catalysts can be tuned, such as the regioselective dimerization of propene to give 2,3-dimethylbutenes, 4-methyl-1-pentene or 2-methyl-1-pentene.…”

“…Catalyst & Chemical Cost (3) , $/t of product 27 30 Recently IFP has completed the development of a new process able to produce selectively pure 1-hexene from ethylene. This new process is based on a proprietary chromium catalyst.…”

Turning a Cr-based heterogeneous ethylene polymerisation catalyst into a selective ethylene trimerisation catalyst

“…This system is comparable with the best currently available Cr-based catalyst for ethylene trimerisation and it was reported for the first time by the group of Hessen and coworkers [10,11]. Cp Cr-based catalysts were reported as very active ethylene polymerisation catalysts [12,13].…”

Synthesis of Novel Trichloride Indenyl Zirconium Complexes with Pendant Pyridine Moiety

“…(2)通过取代的环戊二烯配体与 Zr(NMe 2 ) 4 反应, 经 过胺消除反应, 得到 三(二甲胺基)一茂锆, 再与 BCl 3 反 应得到取代的单茂锆化合物 [6] (Eq. 2); 而三(二甲胺基) 一茚锆若与 3 equiv.的 Me 3 SiCl 也可以得到取代的单茚 锆络合物 [8,14] .…”

“…2); 而三(二甲胺基) 一茚锆若与 3 equiv.的 Me 3 SiCl 也可以得到取代的单茚 锆络合物 [8,14] . 这种方法适用于环戊二烯或茚基配体上 有较大取代基, 但原料 Zr(NMe 2 ) 4 制备比较困难. [18] .…”