Trimerizationof Ethylene with SNS Donor Ligand/Chromium Complexes: Effect of Ligand Structure on Activity and Selectivity

1-hexene is extensively used as co-monomers in the production of linear low density polyethylene (LLDPE). Methylaluminoxane (MAO)-activated chromium (III) complexes of tridentate SNS ligands of the form (RSCH2-CH2)2NH (R= dodecyl, butyl and octyl) have been prepared and tested for the trimerization of ethylene to 1-hexene. The effect of Al/Cr ratio and S donor substitution on 1-C6 selectivity and productivity has been examined. It is shown that when the substitution on S is dodecyl group it will lead to the highest productivity, 159421 g 1-C6/g Cr.h.