Ethylene oligomerization by cobalt(II) diimine complexes/EAO

The catalytic properties of a series of Co(II) diimine complexes Co(N<^>N)Cl-2 [A: N<^>N = N,N'-o-phenylene-bisbenzal; B : N<^>N = N,N'-ethylenebisbenzal; C N<^>N = NX-o-phenylenebis (diphenylmethylene)] in combination with EAO (ethylaluminoxane) as cocatalyst for ethylene oligomerization were investigated. Treatment of the cobal.t(II) Oiimine complexes with EAO in toluene generated in situ active catalysts capable of oligomerizing ethylene to,low-carbon olefins. The catalytic activity and product distribution were affected by reaction conditions; such as temperature, ratios of Al/Co, and reaction time. Activity of 1.30 x 10(5) g oligomers/(mol Co.h) was, observed in the catalytic system of CoCl2(Ph2C = o-NC6H4N = CPh2 with EAO at 200degreesC, with selectivity varying from 94.4% for C4-10 olefins to 87.2% for C4-10 linear alpha-olefins.