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 ph~en~yl~en~ebisbenzal, N,N ′ ethylenebisbenzal) and ethylaluminoxane (EAO). The main products in toluene and at 110-200 ℃ 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 ℃ in the reaction when a catalyst composed of NiCl 2 (PhCH= o NC 6H 4N=CHPh) and EAO was used.