A Selective Chromium Catalyst System for the Trimerization of Ethene and Its Coordination Chemistry



In this paper a novel ligand of the type [PNPNH] is presented for the application in a new homogeneous highly selective ethene trimerization system for the formation of 1-hexene, which consists of the chromium source CrCl3(thf)3, the ligand Ph2PN(iPr)P(Ph)N(iPr)H (1), and Et3Al as an activator in toluene. The excellent characteristics of this new system, e.g. very high selectivity to C6 with highest purity of the C6 fraction (>99 % 1-hexene), activity on a constant level on a long timescale, use of small amounts of Et3Al as a cheap activator, and only very low production of PE, make it to a hot candidate for industrial application. Its organometallic background gives an indication of the nature of the active catalyst species.