Ethylene Oligomerization Catalyzed by Nickel(II) Diimine Complexes

Ethylene oligomerization has been investigated by using catalyst systems composed of nickel(II) diimine complexes (diimine = N, N ′‐ o ‐phenylene bis (salicylideneaminato), N, N′‐o ‐phenylenebisbenzal, N, N ′‐ethylenebisbenzal) and ethylaluminoxane (EAO). The main products in toluene and at 110–200 °C were olefins with low carbon numbers (C 4 —C 10 ). Effects of reaction temperature, Al/Ni molar ratio and reaction period on both the catalytic activity and product distribution were explored. The activity of 1.84 × 10 5 g of oligomer/(mol NI · h), with 87.4% of selectivity to C 4 —C 10 olefins, was attained at 200 °C in the reaction when a catalyst composed of NiCl 2 (PhCH = o ‐NC 6 H 4 N = CHPh) and EAO was used.