Chromium-Catalyzed Highly Selective Oligomerization of Ethene to 1-Hexene with N,N-Bis[chloro(aryl)phosphino]amine Ligands

Different N,N-bis[chloro(aryl)phosphino]amines were synthesized and characterized. The synthesized compounds were tested as ligands in the Cr-catalyzed oligomerization of ethene. The effect of the successive increase of the steric bulk either at one of the P substituents or at the N center on the product distribution of the oligomerization reaction was examined. We found a highly active and selective trimerization system with purities of the hexene fraction up to 99.9% for 1-hexene. Furthermore, we suppose an in situ methylation of the chlorinated ligands into the corresponding N, N-bis[methyl(aryl)phosphino]amines.